STEERING SYSTEM ON 16M GRADER CATERPILLAR

IMPLEMENT AND STEERING SYSTEM

The "M" Series Motor Graders are equipped with a Priority Proportional, Pressure Compensated (PPPC) implement electrohydraulic system.  The PPPC system will sense a demand for flow and the implement and steering pump will upstroke or destroke to provide the necessary flow.  The steering system is an electrohydraulically controlled system.  The Implement ECM, Transmission/Chassis ECM, and steering control valve all work together to provide a primary steering system and a secondary steering system.


The following components make up the implement and steering systems:

- Implement ECMs

- Left hand and right hand joysticks

- Implement and steering pump

- PPPC electrohydraulic control valves

- Steering control valve

- Implement and steering cylinders

- Hydraulic tank

The Implement ECMs are located in the cab, behind the operators seat. All "M" series machines are equipped with two Implement ECMs, with the addition of an auxiliary Implement ECM for attachments and an All Wheel Drive ECM if the machine is equipped with all wheel drive.

Implement ECM (1):  This ECM is the primary Implement ECM. All diagnostic codes are activated by this control module under the module identifier 082.  The other implement control modules communicate diagnostics over the CAN Data Link (J1939) to the Implement ECM (1) which will activate diagnostic codes and events when necessary.  The primary Implement ECM handles all joystick inputs.

Implement ECM 2 (2): This ECM is a secondary Implement ECM that handles all standard implement outputs. This ECM will receive inputs from the primary Implement ECM via the CAN Data Link (J1939) and auxiliary control pod. The ECM will send outputs to attachment auxiliary control valves 1, 2, and 7, if equipped.

All Wheel Drive ECM (3):  This ECM is not an option on the 14M/16M motor graders.  The all wheel drive option will be offered as an attachment on the smaller motor graders.  The All Wheel Drive ECM will control the electronic functions for the all wheel drive system if equipped.

Implement ECM 3 (4):  This ECM is a attachment and acts as a third Implement ECM that will send outputs to attachment auxiliary control valves 3, 4, 5, and 6, if equipped.

Implement Electrical System

Input Components:

Operator Present Switch: An input to the ECM that indicates if an operator is in the operator’s seat.

Key Start Switch:  Provides a signal to the Implement ECM when the operator wants to start the engine.

Hydraulic Oil Temperature Sensor: An input to the ECM with the temperature of the hydraulic oil.

Pilot Filter Bypass Switch: An input to the ECM when the pressure is above 172 kPa (25 psi) in the oil filter.

Secondary Steering Test Switch: An input to the ECM that indicates when the operator wants to test the secondary steering motor and pump.

Hydraulic Pump Pressure Sensor: An input to the ECM that provides the pressure in the steering and implement hydraulic system.

Steering Valve Control Module:  The control module for the steering valve provides two inputs to the Implement ECM.  The control module provides a spool position signal and an error signal to the ECM.

Left Hand Joystick:  Provides 12 different inputs to the Implement ECM.  Some of those inputs include: wheel lean right, articulate right, and steering.

Right Hand Joystick:  Provides 5 different inputs to the Implement ECM.  Some of those inputs include: blade sideshift, circle sideshift, and blade tip.

Right Steering Cylinder Position Sensor:  Signals the ECM the position of the rod in the steering cylinder.

Left Steering Cylinder Position Sensor:  Signals the ECM the position of the rod in the steering cylinder.

Articulation Angle Sensor 1 and 2:  Signals the ECM the angle of the rear frame as compared to the angle of the front frame.

Implement Lockout Switch:  Sends an input signal to the ECM to not energize the implement pilot solenoid to protect from inadvertent movement of the implements.

Auxiliary 1 to 7 Controls (if equipped):  Sends a signal to the ECM communicating the angle of the auxiliary controls.

+24 Battery Voltage:  Unswitched power supplied to the Transmission/Chassis ECM from the battery.

Location Code 2:  The location code pin number 2 is a grounded input signal that establishes the ECM is dedicated to power train and chassis operations.  J1-27 pin on the Transmission/Chassis ECM connector is grounded.

Location Code Enable (GND):  The location code enable is a grounded input signal to the Transmission/Chassis ECM that enables the location code enable feature.  J1-32 pin on the Transmission/Chassis ECM connector is grounded.

Output Components:

Implement Pilot Solenoid:  This ON/OFF solenoid valve is an output from the Implement ECM.  This valve opens the flow of pilot oil to the implement control valves.

Blade Left Raise/Lower Solenoids:  The proportional solenoid valves are an output from the Implement ECM.  The solenoid valve sends a proportional amount of pilot oil to the blade raise/lower spool depending on the amount of current applied to the solenoids.

Blade Right Raise/Lower Solenoids:  The proportional solenoid valves are an output from the Implement ECM.  The solenoid valve sends a proportional amount of pilot oil to the blade raise/lower spool depending on the amount of current applied to the solenoids.

Articulate Left/Right Solenoids:  The proportional solenoid valves are an output from the Implement ECM.  The solenoid valve sends a proportional amount of pilot oil to the articulation spool depending on the amount of current applied to the solenoids.
Wheel Lean Left/Right Solenoids:  The proportional solenoid valves are an output from the Implement ECM.  The solenoid valve sends a proportional amount of pilot oil to the wheel lean spool depending on the amount of current applied to the solenoids.

Blade Sideshift Left/Right Solenoids:  The proportional solenoid valves are an output from the Implement ECM.  The solenoid valve sends a proportional amount of pilot oil to the blade sideshift spool depending on the amount of current applied to the solenoids.

Circle Drive Clockwise/Counterclockwise Solenoids: The proportional solenoid valves are an output from the Implement ECM. The solenoid valve sends a proportional amount of pilot oil to the circle drive spool depending on the amount of current applied to the solenoid.

Blade Tip Forward/Backward Solenoids:  The proportional solenoid valves are an output from the Implement ECM.  The solenoid valve sends a proportional amount of pilot oil to the blade tip spool depending on the amount of current applied to the solenoid.

Centershift Left/Right Solenoids:  The proportional solenoid valves are an output from the Implement ECM.  The solenoid valve sends a proportional amount of pilot oil to the centershift spool depending on the amount of current applied to the solenoid.

Auxiliary 7 Control Solenoids:  The proportional solenoid valves are an output from the Implement ECM.  The solenoid valve sends a proportional amount of pilot oil to the auxiliary spool depending on the amount of current applied to the solenoid.

Steering Valve Control Module:  The control valve module for the steering valve is an output of the Implement ECM.  The Implement ECM provides power and a command signal to the control module.

Backlight Relay:  The Implement ECM energizes the backlight relay when any of the worklamp switches have been turned to the ON position.

Auxiliary Lever 1 Float Indicator:  The Implement ECM will send a signal to Messenger to illuminate the float indicator when the control has been placed in the float position.

Auxiliary Lever 4 Float Indicator:  The Implement ECM will send a signal to Messenger to illuminate the float indicator when the control has been placed in the float position.

Auxiliary Lever 6 Float Indicator:  The Implement ECM will send a signal to Messenger to illuminate the float indicator when the control has been placed in the float position.

+5 Volt Supply:  Power supplied to the components from the Implement ECM.

+8 Volt Supply:  Power supplied to the components from the Implement ECM.

+10 Volt Supply:  Power supplied to the components from the Implement ECM.

Left Joystick Electronic Operation.

The left joystick has fourteen functions.  The gear selection, neutral articulation, and direction functions use switch type inputs.  The wheel lean function uses linear pushbuttons that send a PWM signal to the Implement ECM.  The left blade lift, steering, and articulation functions use hall cell type sensors that send PWM signals to their corresponding ECMs.

NOTE:  The joystick is not serviceable.  The joystick must be replaced if any switch or sensor fails.

The left joystick contains three steering sensors that are necessary for correct steering operation. All three sensors send a PWM signal to both the Implement ECM and the Transmission/Chassis ECM.  Steering sensors 1 and 2 are powered from the Implement ECM.  Steering sensor 3 is powered from the Transmission/Chassis ECM.

A Level 3 Warning occurs when any steering lever position sensor fails.  The machine will continue to steer normally (with an active Level 3 warning) using the two remaining sensors
There are some points to consider when diagnosing FMIs for the steering lever position sensors:

- Verify that CID 0041 (8 volt power supply) for the Implement ECM (MID 082) does not have any       active codes.  Correct any problems with the 8 volt power supply if any diagnostic codes are               active.
- The correct operating temperature range for the steering sensors is -40° C -40° F) to
   75° C (167°F).  Normalize the cab environment to the acceptable temperature range if an FMI 03       or  and FMI 08 code becomes active for a steering sensor when the cab environment is at extreme       temperatures.  Verify an active FMI is still present before continuing to troubleshoot.
  The Transmission Chassis ECM (MID 027) and the Implement ECM (MID 082) receive an input        signal from the steering lever position sensors.  Both ECMs can activate a diagnostic code for all        three sensors.  It is likely that the sensor is operating correctly if one ECM has activated a                    diagnostic code and the other ECM has not.  When this occurs, a poor connection in the machine        harness would be suspected.  When both ECMs have activated the diagnostic code, either the              sensor  OR a harness problem could be the cause. It is very unlikely that both ECMs have failed          when both ECMs have activated the diagnostic code.

Right Joystick Electronic Operation.

The right joystick has twelve functions.  Throttle resume and differential lock are switch type inputs.  The remaining functions are PWM inputs.  With the exception of the differential lock switch and the throttle resume switch, all inputs from the right joystick go to the Implement ECM.  Power to the right joystick is supplied by the Implement ECM and the Transmission/Chassis ECM.

NOTE:  The joystick is not serviceable.  The joystick must be replaced if any switch or sensor fails.

The right joystick receives power from the Implement ECM and the Transmission/Chassis ECM.  Ensure that you identify the correct Module Identifier (MID) when troubleshooting a CID 1482 (10 volt power supply).

There are some points to consider when diagnosing FMIs for the right joystick:

* Verify that CID 1482 (10 volt power supply) for the Implement ECM and Transmission/Chassis          ECM does not have any active codes.  Correct any problems with the 10 volt power supply if any        diagnostic codes are active.

* The correct operating temperature range for the steering sensors is -40° CR (-40° F) to 75° CR             (167° F).  Normalize the cab environment to the acceptable temperature range if an FMI 03 or and      FMI 08 code becomes active for a steering sensor when the cab environment is at extreme                 temperatures.  Verify an active FMI is still present before continuing to troubleshoot.

The hydraulic tank (1) is located behind the engine on the left side of the machine.  The return filter (2) is located next to the hydraulic tank (1) on the left side of the machine.  The return filter (2) removes any debris in the hydraulic oil before the oil returns to the hydraulic tank. The return filter (2) has a filter bypass valve in it.  The filter bypass is not monitored by any ECMs.  The filter bypass will allow dirty oil to flow to the hydraulic tank if the filter element becomes plugged.  Be sure to follow the recommended service intervals for this filter.

The implement and steering pump (1) is located on the back left side of the engine.  This pump is a variable displacement piston pump that has a pump control (2) to allow the pump to vary the amount of flow that is produced.  The pressure tap (3) is installed in the signal line at the pump control valve.  The pressure tap (3) provides a location to test the signal pressure of either the steering signal or implement signal.

The implement and steering control manifold contains the following components

Pressure tap (1):  This tap is used for testing the pressure at the outlet of the implement and steering pump.

Pressure sensor (2):  This sensor monitors the pressure at the outlet of the implement and steering pump.

Relief valve (3):  This valve protects the implement and steering supply circuit from high pressure.  The relief valve is adjustable.

S•O•S port (4):  This port is used for pulling an oil sample from the outlet of the implement and steering pump.

Pressure reducing valve (5):  This valve limits the pressure in the implement pilot circuit.  The pressure reducing valve is adjustable.

Pressure tap (6):  This tap is used for testing the pressure in the pilot system.

Implement pilot solenoid (7):  This solenoid directs or prevents oil flow to the implement pilot system.  The implement lockout switch in the cab energizes or de-energizes this solenoid. Supply oil will be directed to the implement pilot system when this solenoid is energized.  No oil will be directed to the implement pilot system when the solenoid is de-energized.

The pilot oil filter (1) removes any debris from the oil before the oil travels to the pilot system. The pilot filter is located behind the transmission on the left side of the machine.  The pilot oil filter has a bypass switch (2) that is monitored by the Implement ECM.  The pilot filter also has an S•O•S port (3).

The steering control valve (1) is located in front of the cab.  The secondary back-up steering solenoids (2) are located above the steering control valve (1).
The steering control valve (1) is an electro-hydraulic valve that consists of two distinct systems. The first system is the hydraulic section (3), which has several main functions.  The hydraulic section has a priority valve that will ensure that the steering circuit demands are met before any hydraulic oil is sent to the implement circuit.  The hydraulic section also has a pressure reducing valve that will meter pilot oil to the secondary back-up steering solenoids.  The last main function of the steering control valve is to direct pump supply oil to the steering cylinders when the operator requests a turn with the left joystick.  The steering control valve has several other internal components that will be discussed in more detail with a schematic.
The second system on the steering control valve is the electronic system.  The Implement ECM controls the primary steering functions.  The Implement ECM will send a control signal to the steering control module (4) when the left joystick changes positions (operator requests a steer left or right).  The steering control module will direct pilot oil to move the directional control spool inside the steering control valve one direction or another.  The steering cylinders will begin to move.  The ECM will monitor the position of the steering cylinders as well as the position of the directional control spool inside the steering control valve.  The Implement ECM will decrease the control signal to the steering control module as the steering cylinders approach the desired position. The steering control module (4) also has an LED (5) which displays the operational status of the module.

The Implement ECM will not allow the steering system to function until certain conditions are met.  The conditions are as follows:

- Engine operating
- Sufficient hydraulic system pressure
- Operator present
- Park brake ON, transmission in NEUTRAL
- No steering cylinder faults


In addition to those conditions, the left joystick position must be aligned with the angle of the front wheels before the Implement ECM will allow the steering system to operate.  The operator accomplishes this by slowly sweeping the joystick through the full range of travel for the left/right axis.  Other conditions that may prevent the steering system from being enabled are as follows:

- Sweeping the joystick too fast
- Not sweeping the joystick through a full range of motion
  Front wheel position out of range:  Sweeping the joystick may not align the joystick to the steering      cylinders if the wheels are out of range (due to damage or extreme angle).  The wheels must be            manually moved back into range if this condition occurs. Actuating the wheel lean function left or      right may help move the wheels into an acceptable range


ElECTRONIC PRIMARY STEERING CONTROL

 There are three types of signals that are communicated between the Implement ECM and the Steering Control Valve.  The signals are as follows:

* Steering control signal:  The steering control signal is a PWM signal sent from the Implement ECM to the steering control module.  The duty cycle of the control signal is dependent on the input signals from the steering cylinder position sensors and the left joystick position sensor to the Implement ECM.  The steering control module will adjust the position of the directional valve spool based on the duty cycle of the control signal. The Implement ECM does not monitor the control signal circuit for diagnostics.  The steering control module will detect a problem such as a high or low voltage in the signal circuit and will send an error signal to the implement ECM.  The Implement ECM will turn the power supply to the steering control module OFF if the steering control module sends and error signal.  The Implement ECM will also send a request to the Transmission/Chassis ECM to activate the secondary steering system.

* Spool position signal:  The Implement ECM receives an input from the steering control module that indicates the position of the directional valve spool inside the steering control valve.  The Implement ECM uses this information to determine if the steering valve control module is responding correctly to the steering control signal.  The Implement ECM monitors the spool position circuit for diagnostics.  The Implement ECM will turn the power supply to the steering control module OFF if the ECM detects a high voltage condition, a low voltage condition, or a short.  The Implement ECM will also send a request to the Transmission/Chassis ECM to activate the secondary steering system in the event of a steering control valve diagnostic.


* Error signal:  The steering control module monitors it’s own operation and monitors the Implement ECM circuits that are connected to the module.  The steering control module will send an error signal to the Implement ECM if the steering control module detects electrical problems.  The Implement ECM will turn the power supply to the steering control module OFF if the steering control module sends and error signal.  The Implement ECM will also send a request to the Transmission/Chassis ECM to activate the secondary steering system.

The steering control valve is equipped with a status LED.  This LED will be green if there are no faults.  The LED will flash red if there is an input signal fault.  Closed loop faults will cause the LED to be constantly illuminated red.

The "M" series motor graders are equipped with a secondary steering system.  The Transmission/Chassis ECM and the Implement ECM work together to turn on the secondary steering system if the primary steering system fails.  The Transmission/Chassis ECM and the Implement ECM monitor the left joystick, steering cylinder position sensors, pump pressure sensor, and the articulation sensors.
The Implement ECM will send a PWM signal to the Transmission/Chassis ECM if the secondary steering system needs to be activated due to a secondary steering test or a problem in the primary steering system.  The duty cycle of the PWM signal will be used to determine which specific secondary steering component needs to be activated.  The PWM duty cycle is as follows:

- 20 percent PWM duty cycle:  Normal operation, no request to activate.
- 40 percent PWM duty cycle:  Request to activate the secondary steering pump motor only.
- 60 percent PWM duty cycle:  Request to activate the secondary steering pilot solenoid valves only.
80 percent PWM duty cycle:  Request to activate the secondary steering pump motor and the secondary steering pilot solenoid valves


The Implement ECM will send the request signal to activate the secondary steering system when any of the following machine system conditions are detected:

- An active CID 2202 FMI 12 "Steering Valve Control Module Error" diagnostic code is present.

- A failure of the main hydraulic pump.

- Steering motion is detected when no primary steering command is present.

- Steering motion is not detected when a primary steering command is present.

- Steering motion is detected in the wrong direction.

- A manual secondary steer test has been requested.

- An automatic secondary steer pump test is being performed at initial start up.

NOTE:  The secondary steering system is designed to be used for a short period of time in order to move the machine to an area where a safe shutdown of machine operation can take place.  Operating the secondary steer pump motor for more than a short period of time will cause the secondary steer pump motor to overheat

The Transmission/Chassis ECM will activate the secondary steering pilot solenoid valves (1) or (2) when a 60 percent duty cycle is sent from the Implement ECM.
The Transmission/Chassis ECM will send a PWM output signal to the appropriate solenoid based on steering cylinder position sensors and the left joystick position sensor.  The secondary steering pilot solenoid will direct pilot oil to one side of the the directional valve spool which is inside the steering control valve.  The amount of oil directed to the spool is based on the duty cycle of the PWM signal sent by the Transmission/Chassis ECM.

The secondary steering system will remain active until the machine is turned OFF.  The primary steering system will be active when the machine is restarted only if the condition that caused the activation of the secondary steering system is no longer present.

The steering control valve (1) has a screen (2) located in the supply port for the solenoids.  The screen helps to protect the solenoids from any debris in the hydraulic system.
Secondary steering manifold (3) has a screen (4) located in the supply port for the secondary steering solenoids.  The screen helps to protect the solenoids from any debris in the hydraulic system

The secondary steering pump (arrow) is located just behind the articulation hitch.  The secondary steering pump is accessible from underneath the machine.
The Transmission/Chassis ECM will energize the secondary steering relay when a 40 percent duty cycle is sent from the Implement ECM to the Transmission/Chassis ECM.  The secondary steering relay will energize the secondary steering pump and turn the secondary steering motor ON.

The secondary steering system has two tests that can be performed to determine if the secondary steering system is working.  The tests are as follows:

- Automatic secondary steering test:  The automatic secondary pump test is performed each time the engine is started.  The Implement ECM will log an event if the secondary steering pump is not responding.

- Manual secondary steering test:  The test can be performed with Messenger and the engine OFF or with the engine running.  To perform the test with Messenger, navigate to the "Service Test" menu and then select "Dead Engine Steering."  Once "Dead Engine Steering" has been selected, the Transmission/Chassis ECM will energize the secondary steering relay.  The secondary steering solenoids will be activated by the Transmission/Chassis ECM when 10000 kPa (1450 psi) has been detected by the Implement ECM.  To perform the test engine running, the ground speed must be zero. Hold the secondary steering test switch in for 10 seconds.  The Transmission/Chassis ECM will activate the secondary steering relay.  The Implement ECM will signal the Transmission/Chassis ECM to enable the secondary steering solenoid valves once the Implement ECM detects 10000 kPa (1450 psi) in the steering system.
NOTE:  If the steering wheels do not follow the operator’s commands, the secondary steering system must be repaired before the machine can be operated safely.

Steering Hydraulic System Operation

The implement and steering pump provides flow to the steering control valve.  Supply oil will enter the steering control valve and flow to the priority valve.  The priority valve is held to the left by the force of the spring.  The priority valve will direct supply oil to the steering circuit until the steering circuit is fully charged.  Once the steering circuit is fully charged, the priority valve will shift to the right and direct charge oil to the implement circuit.

The compensator valve directs steering priority oil to several locations.  The first location is the pressure reducing valve and the second location is the direction spool.  The compensator valve also has an internal passage that contains two orifices.  One internal orifice meters oil to the left side of the compensator valve.  The other internal orifice meters supply oil into the load sense circuit.

Pump supply oil is blocked when the direction spool is in the HOLD position.  Oil in the load sense circuit is allowed to flow through a passage in the direction spool and to the metering valve.  The purpose of the metering valve is to maintain enough pressurized oil in an internal passage to supply the steering control solenoids with enough oil to shift the direction spool when the operator requests a turn.
The pressure reducing valve directs pump supply oil to the secondary steering control solenoids.  The pressure reducing valve will block supply oil when the secondary steering control solenoid circuit reaches about 3000 kPa (435 psi).

The signal relief valve limits the pressure in the signal circuit.  The signal relief valve will direct excess oil to tank if the signal circuit pressure is above the setting of the relief valve.

The crossover relief valves protect the steering cylinders for sudden pressure spikes.  The crossover relief valves will dump oil from one side of the cylinder to the other if the pressure in the steering cylinders raises above the setting of the relief valves.

The steering control solenoids work in pairs to shift the direction spool in the steering control valve.  The lower steering control solenoids block supply oil which is maintained by the metering valve when no steering request is being made by the operator.  The upper steering control solenoids are open to tank when no steering request is being made by the operator.

The secondary steering control solenoids are used as a back-up in case the primary steering control solenoids fail.  The secondary steering control solenoids meter pilot oil to tank when the Transmission/Chassis ECM is not energizing one of the secondary steering control solenoids.

The Implement ECM sends a steering request to the right steering control solenoids when the operator makes a right turn request.  The upper and lower right steering control solenoids energize and shift to the left.  Pilot oil that is maintained by the metering valve is directed past the lower right steering control solenoid and the right shuttle valve to the right side of the direction spool.  The direction spool will shift left and direct pump supply oil to the steering cylinders.  The direction spool will also direct pump supply oil into the load sense circuit to seat the check valve

The Transmission/Chassis ECM sends a steering request to the secondary right turn solenoids when the operator makes a right turn request and the primary steering solenoids are not functioning properly.  The solenoid will energize and shift downward.  Pilot oil that is maintained by the pressure reducing valve is directed through the solenoid, and past a shuttle valve to the right side of the direction spool.  The direction spool will shift left and direct pump supply oil to the steering cylinders.  Pump supply oil will also seat the check valve in the load sense circuit after the direction spool has shifted left

The steering cylinders (1) are located at the front of the machine.  The steering cylinders have an internal position sensor which allows the Implement ECM and the Transmission/Chassis ECM to monitor the steering angle of the steering cylinders.  This signal is compared to the position of the steering lever sensors for diagnostic purposes
The steering cylinder position sensors can be changed on the "M" series graders. New cylinder extension and retraction parameters must be entered into Cat ET if a cylinder position sensor is changed.

New software files must be downloaded and flashed into the Implement ECM upon replacement of a steering cylinder.

NOTE: The steering cylinder position sensors are powered from two different ECMs. The left sensor is powered from the Transmission/Chassis ECM and the right sensor is powered from the Implement ECM

The steering cylinders are equipped with position sensors.  The sensor sends a Pulse Width Modulated (PWM) signal to the ECM with the cylinder piston position within the piston stroke.

The sensor uses the magnetostrictive principle. A wire is stretched inside the length of the sensor rod in order to form a waveguide. At time zero, a current pulse is transmitted down the wire by the electronics in the sensor head. At the point where the pulse reaches the magnetic field of the magnet, a pulse is generated and sent back to the sensor head.  Internal electronics convert the time zero to the time it takes the return pulse to reach the sensor head into an electronic PWM signal.  The pulse width is directly proportional to the position of the magnet. The sensor frequency is 500 Hz.

The articulation position sensors are located on the frame behind the cab
Articulation position sensor 1 (1) is powered by the Implement ECM and is monitored by the Implement ECM and the Transmission/Chassis ECM. Articulation position sensor 2 (2) is powered by the Transmission/Chassis ECM and is monitored by the Implement ECM and the Transmission/Chassis ECM.

Both machine articulation position sensors must track within 3.5 degrees (angular) of each other or a FMI 14 will be activated.  The cause for this is usually loose, incorrectly assembled, or damaged linkages.

The machine articulation angle will be limited when traveling in SEVENTH SPEED FORWARD, EIGHT SPEED FORWARD, and SIXTH SPEED REVERSE or, if the
transmission gear is UNKNOWN.  The machine articulation will be limited to a maximum of
5.5 degrees (left or right) while traveling with these conditions.  When these conditions no longer exist, the operator will be able to fully articulate the machine.

The maximum gear will be limited if the machine is articulated more the 6.5 degrees (left or right).  The machine will be allowed to shift up to SIXTH SPEED FORWARD or FIFTH SPEED REVERSE with the machine articulated more than 6.5 degrees.  When the machine is articulated to less than 6.5 degrees, the operator will be able to shift above
SIXTH SPEED FORWARD or FIFTH SPEED REVERSE


Tech tip:  Using Electronic Technician, check the articulation position sensors’ duty cycle if a CID 615 FMI 14 or a CID 2252 FMI 14 diagnostic code is active.  Calibrate the sensors if the duty cycle is within specification. Adjust the mechanical linkage of the sensors if the duty cycle is out of specification.  Recalibrate the sensors after you adjust the mechanical linkage

The center shift lock (1) is located behind the support arms for the blade cylinders.  The center shift lock (1) uses oil from the implement pilot system to lock the center shift link (2) into place.  The center shift solenoid (3) directs oil to retract or extend the center shift lock.  The mechanical switch (4) will illuminate an indicator on the dash when the center shift lock is retracted.  The indicator for the center shift lock is located below the instrument cluster on the right side of the console.

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