Cat® Grade Control Cross Slope System for Motor Graders Caterpillar

The following is a list of Diagnostic Trouble Codes (DTCs). When a diagnostic code becomes active, refer to the Troubleshooting section of this manual for a specific troubleshooting procedure.

Troubleshooting the Cat^® Grade Control System (Cross Slope)

Note: Before performing maintenance, ensure the following:

• The blade is fully rested on the ground

• The parking break is engaged

• The key switch on the OFF position and the master disconnect switch is disconnected

• Machine is in a safe condition and away from any working personal

• All the safety steps to perform the maintenance procedure on the machine has been implemented.

Troubleshooting the Cat Grade Control System Sensors

The following is the list of codes that are associated to the Cat^® Grade Control Sensors Data link and calibrations.

Table 1

Implement ECM 1 (MID 82)
DTC	Failure Mode (FMI)	Description
871	09	Inclination Sensor / Abnormal Update
908	09	Blade Rotation Position Sensor / Abnormal Update
3694	09	Blade Slope Sensor / Abnormal Update

Code 871 is related to the Inclination (Main-Fall) Sensor.

Code 908 is related to the Blade Rotation Sensor.

Code 3694 is related to the Blade Slope Sensor.

Probable Causes

• Intermittent wires connection with CAN data link.

• CAN Data link wires shorted to the machine ground, machine power circuit or both CAN wires are shorted together.

Note: When CAN Wires Shorted to the machine ground or to each other, the entire CAN Data Link Bus and every component connected to it will be impacted and there will be more codes and failure modes related to each of this component.

• Sensor has no power supply.

• Defective sensor

• Defective Implement ECM

Note: Machine ECM failure is unlikely.

Steps to Isolate the Problem and Solution

Perform the below steps to troubleshoot the sensors:

Note: After completing the troubleshooting step, ensure that the step is checked correctly and then move to the next troubleshooting step. If any of the steps is incorrectly checked, stop and investigate it, then correct it.

1. Measure the power supply to the sensor, ensure that there is a 24 volts between Pin A+ and Pin B ground, Refer to the Table 2 below or the machine schematic for more information.

2. Visually check the harness wires and the connectors from the sensors to the implement ECM, ensure that there is no damages or broken wires.

3. Perform resistance (Ohm) check between the CAN high and CAN low wires. Ensure that there is a 60 Ω (Ohms) between them.

4. Perform resistance (Ohm) check between the CAN wires from the sensor connector and the machine ground. Ensure that there is no conductivity between them.

5. Perform a resistance (Ohm) check between the CAN wires from the sensor connector and the machine power supply circuit. Ensure that there is no conductivity between them.

6. Perform a resistance (Ohm) check between the CAN wires from the sensor connector to the machine Implement ECM Connector. Ensure that there is a conductivity between the sensor connector pins and the ECM connector pin. Refer to the Table 2 or the machine schematic for more information.

7. Replace the sensor that is related to the diagnostic code.

8. Replace the Machine Implement ECM.

   Note: Failure of machine ECM is highly unlikely.

   Note: Refer to the Table 2 and the machine schematic or the connector contact descriptions section of this manual.

Cross Slope System Sensor Connectors

Illustration 1	g06071963
Connector contact

Table 2

Pin	Contact Description	Implement 1 ECM Connector/Pin	Power Module PM400 Connector/Pin
A	switch power	-	GR-C2-A or RV-C11-A
B	switch power return	-	GR-C2-B or RV-C11-B
C	J1939 CAN A data link high	J2-67	-
D	J1939 CAN A data link low	J2-68	-
E	switched power return (AWAKE RTN)	-	GR-C2-F or RV-C11-F
F	switched power return (AWAKE RTN)	-	GR-C2-F or RV-C11-F

Illustration 2	g06089533
CAN Data Link

Table 3

Implement ECM 1 (MID 82)
DTC	Failure Mode (FMI)	Description
871	13	Inclination Sensor / Out of Calibration
908	13	Blade Rotation Position Sensor / Out of Calibration
3694	13	Blade Slope Sensor / Out of Calibration

Code 871 is related to the Inclination (Main-fall) Sensor.

Code 908 is related to the Blade Rotation Sensor.

Code 3694 is related to the Blade Slope Sensor.

When any of the Sensors become loose from the mounting bracket, reinstalled or replaced the Cat Grade control System requires that sensor to be realigned and recalibrated in order for the system to be accurate. Refer to Testing and Adjusting Manual for instructions on aligning and calibrating the Cat Grade Control Sensors.

• The sensor is not secured to the bracket

• The sensor has been removed, reinstalled, or replaced

• Sensors that related to the diagnostic code requires calibration

• Sensor failure

1. Ensure that the sensor related to the diagnostic code is secured to the mounting bracket.

2. Measure the power supply to the sensor connector between Pin A Positive and Pin B RTN GND, ensure that there is close to 24 volt present. Correct any problem.

3. Ensure that the sensor is aligned properly and recalibrate it. Refer to the realigning and calibration section on this manual.

4. Replace the sensor that related to the diagnostic code, align it and then calibrate it.

Table 4

Implement ECM 1 (MID 82)
DTC	Failure Mode (FMI)	Description
3695	03	Blade Slope Sensor Power Supply / voltage above normal
	04	Blade Slope Sensor Power Supply / voltage below normal
3696	03	Blade Rotation Angle Sensor Power Supply / voltage above normal
	04	Blade Rotation Angle Sensor Power Supply / voltage below normal
3699	03	Inclination (Main fall) Sensor Power Supply / voltage above normal
	04	Inclination (Main fall) Sensor Power Supply / voltage below normal

Code 3695 with FMI 03 or 04 is related to the Blade Slope Sensor power supply circuit.

Code 3696 with FMI 03 or 04 is related to the Blade Rotation Sensor power supply circuit.

Code 3699 with FMI 03 or 04 is related to the Inclination (Main-fall) Sensor power supply circuit.

Note: The System will generate a Level 2 warning when any of the diagnostic codes in the above table with FMI 03 and FMI 04 become active.

• Intermittent or damages to harness wires connection to the sensor from the Power Module PM400.

• The out power supply from the power module PM400 to the sensor is missing.

• The power module PM400 input power supply is missing.

Note: When the power model power supply is missing, all the system sensors will generate the same failure mode indicating that there is no power supply to them.

• An open circuit

• A component failure of the sensor or the power module PM400.

• Machine implement ECM failure.

Note: Failure of machine ECM is highly unlikely.

1. Visually check the wires and the connectors from the sensors to the implement ECM, ensure that there is no damages or broken wires. Correct any problems.

2. Disconnect the sensor from the machine harness connector and while the machine key switch is in the ON position measure the power supply between Pin A + and Pin B ground ensure that there is a proper power supply (close to 24 volts) from the power model PM400. Correct any problems.

   Refer to the Table 5 and 6 or the machine schematic.

3. If there is a power supply present while the sensor is disconnected from the machine harness, measure the power supply to the sensor while it is connected to machine by inserting needle group described in service tool section from the back of the sensor connector to measure the power supply between Pin A + and Pin B ground, ensure that there is sufficient power supply present (close to 24 volts) from the power module PM400 and there is no disappearance or significant drop of the voltage to ensure that there is no internal shortages inside the sensor circuit. Replace the sensor if significant drops of the voltage happened while it is connected to the machine harness.

4. If the power supply is missing to the sensor while the connector is disconnected, ensure that there is a power supply present to the input and the output of the power module PM400 and also the awake and awake RTN is present. Refer to the Table 5 and 6 or the machine schematic for more information.

5. Replace the sensor or the power model PM400 if failure occurs.

6. Replace the Implement ECM.

   Note: Failure of machine ECM is highly unlikely.

Illustration 3	g06071963
Connector contact

Table 5

Pin	Description
A	+ BATT 1
B	GND
C	+ BATT 2
D	GND
E	-
F	-
G	+ BATT 3
H	GND

Illustration 4	g06071963
Connector contact

Table 6

Pin	Description
A	Switched power 1
B	Switched power RTN 1
C	Switch power 2
D	Switched power RTN 2
E	Awake
F	Awake RTN
G	Switched power 3
H	Switched power RTN 3

Troubleshooting the Cat Grade Control System Operator Control (Automatic/Manual) Switches

Table 7

Implement ECM 1 (MID 82)
DTC	Failure Mode (FMI)	Description
2258	03	Left Blade Control Mode (Automatic/Manual) Switch / voltage above normal
	04	Left Blade Control Mode (Automatic/Manual) Switch / voltage below normal
2259	03	Right Blade Control Mode (Automatic/Manual) Switch / voltage above normal
	04	Right Blade Control Mode (Automatic/Manual) Switch / voltage below normal

Code 2258 with FMI 03 and 04 is related to the Left Blade Control Mode (Automatic/Manuel) Switches circuit.

Code 2259 with FMI 03 and 04 is related to the Right Blade Control Mode (Automatic/Manuel) Switches circuit.

Note: The System will generate a Level 2 warning when any of the diagnostic codes in the above table with FMI 03 and FMI 04 become active.

Probable Causes

• Intermittent or damages to the switch wiring circuit.

• A component has failed (Switch).

• A component has failed (Machine Implement ECM).

Note: Failure of the ECM is highly unlikely.

Steps to Isolate the Problem and Solution

1. Visually check the wires and the connectors from the switch connector to the implement ECM, ensure that there is no damages or broken wires. Correct any problems.

2. Perform contact connections check using an Ohm meter to the switch pins while it is disconnected from the machine harness and replace it, if it is not working properly. Refer to the Table 9.

3. Perform a resistance (Ohm) check of the circuit wires to the machine Implements ECM Connector. Refer to the Table8 or the machine schematic for more information.

4. Replace the Implement ECM if all conditions and steps above are correct and functioning in a proper way.

   Note: Failure of machine Implement ECM is highly unlikely.

5. To troubleshoot the automatic/manual switches on the machine equipped with Advance Joystick, refer to machine schematic.

Right and Left Blade Control Mode Switch (Auto/Man Switch)

Illustration 5	g06076493

Table 8

Wiring Table			LH/ RH Switch ECM Input Signal	LH/ RH Switch Implement ECM Input Signal
Pin	Circuit	Color
A	N/C	White	J2/53 (N/C)	J2/60 (N/C)
B	N/O	Brown	J2/52 (N/O)	J2/59 (N/O)
C	Common	Black	J2/22 Digital Return	J2/22 Digital Return (GND)

Ohm checking the RH/LH Side Blade Control Mode Switches (Auto/Man switches) using ohm meter.

Disconnect the Auto/Man Switch from the machine harness and perform the following contact connection check using the ohm meter

Table 9

RH/LH Auto/Manual Switch
Contact Connections Between	When Switch Not Pressed	When Switch Pressed
PIN B and PIN A	Closed Circuit	Opened Circuit
PIN B and PIN C	Opened Circuit	Closed Circuit
PIN A and PIN B	Opened Circuit	Opened Circuit

Table 10

Implement ECM 1 (MID 82)
DTC	Failure Mode (FMI)	Diagnostic Code Procedure
2261	03	Left Desired Grade Offset (Increment/Decrement) Switch / voltage above Normal
	04	Left Desired Grade Offset (Increment/Decrement) Switch / voltage below Normal
2262	03	Right Desired Grade Offset (Increment/Decrement) Switch / voltage above Normal
	04	Right Desired Grade Offset (Increment/Decrement) Switch / voltage below Normal

Code 2261 with FMI 03 or 04 is related to the Left Desired Grade Offset (Increment/decrement) Switch power circuit.

Code 2262 with FMI 03 and 04 is related to the Right Desired Grade Offset (Increment/Decrement) Switch power circuit.

Note: The System will generate a Level 2 warning when any of the diagnostic codes in the above table with FMI 03 and FMI 04 become active.

• Intermittent or damages to the switch wiring circuit.

• A component has failed (Switch).

• A component has failed (Machine Implement ECM).

Note: Failure of ECM is highly unlikely.

1. Visually check the machine harness from the switch connector to the implement ECM connector, ensure that there is no damages or broken wires. Correct any problem.

2. Perform contact connections check using an Ohm Meter to the switch pins while it is disconnected from the machine harness and replace it, if it is not working properly. Refer to the Table 13 or the machine schematic for more information.

3. Disconnect the sensor connector and the machine Implement ECM connector and perform a resistance (Ohm) check of the wires circuit from the Switch Connector to the machine Implements ECM Connector, correct any problem. Refer to the Table 12 and 13 or the machine schematic for more information.

4. Replace the Implement ECM.

   Note: Failure of the machine Implement ECM is unlikely.

5. For troubleshooting the RH/LH Increment/Decrement Switches on machine equipped with advanced Joystick, refer to machine schematic.

Table 11

Implement ECM 1 (MID 82)
DTC	Failure Mode (FMI)	Description
2261	02	Left Desired Grade Offset (Increment/Decrement) Switch / Data Erratic Intermittent or incorrect
2262	02	Right Desired Grade Offset (Increment/Decrement) Switch / Data Erratic Intermittent or incorrect

Code 2261 with FMI 02 is related to the Left Desired Grade Offset (Increment/Decrement) Switch data.

Code 2262 with FMI 02 is related to the Right Desired Grade Offset (Increment/Decrement) Switch data.

Note: The System will generate a Level 2 warning when any of the diagnostic codes in the above table with FMI 02 become active.

• The switch digital Input signal to the Implement ECM is intermittent or missing.

1. Visually perform a check to the machine harness from the switch connector wires to the implement ECM connector ensure that there is no damages or broken wires, correct any problem that found.

2. Perform contact connection test of the switch while it is disconnected form the switch. Refer to the Table 13 or the machine schematic.

3. Perform a resistance check from the switch connector to the Implement ECM connector.

4. Disconnect the sensor connector and the machine Implement ECM connector and perform a resistance (Ohm) check of the wires circuit from the Switch Connector to the machine Implements ECM Connector, correct any problem. Refer to the Table 12 and 13 or the machine schematic for more information.

5. Replace the Switch if it is not working properly.

6. Replace the Implement ECM.

   Note: Failure of Implement ECM is highly unlikely.

Illustration 6	g06076496
RH/LH side offset switch (Increment/Decrement switch)

Table 12

Offset Switch (INC/DEC switch)		Implement ECM Connector J2
Pin	Function	RH Side Switch PIN	LH Side Switch PIN
1	INC/DEC signal - INC	46	55
2	Digital return signal (GND)	22	22
3	Pin 3 connected to pin 5
4	Switch neutral signal	45	54
5	Pin 5 connected to pin 3
6	INC/DEC signal - DEC	47	56

To check the switch with an ohm meter, refer to the Table 13 contact connection between the switch pins.

Disconnect the switch connector form the machine harness and perform the following checks using an ohm meter.

Table 13

Contact Connection Between	Neutral Position	Increment Position (INC)	Decrement Position (DEC)
PIN 2 to PIN 1	Open	Connected	Open
PIN 2 to PIN 3	Connected	Open	Connected
PIN 2 to PIN 4	Connected	Open	Open
PIN 2 to PIN 5	Connected	Open	Connected
PIN 2 to PIN 6	Open	Open	Connected
PIN 5 to PIN 1	Open	Open	Open
PIN 5 to PIN 2	Connected	Open	Connected
PIN 5 to PIN 3	Connected	Connected	Connected
PIN 5 to PIN 4	Connected	Connected	Open
PIN 5 to PIN 6	Open	Open	Connected