Diagnostic Test
TECH TIPS:
- Note that the RDM will only have a smart actuator on the two speed systems.
- If the DTCM is replaced, the Restore Vehicle Configuration procedure must be performed for the system to operate correctly and not set a configuration mismatch DTC. A configuration mismatch can also set if an incorrect smart actuator is installed.
COMMUNICATION DIAGNOSTICS (U1203, U1204): This diagnostic applies to both the PTU and RDM. Note that the RDM will only have a smart actuator on the two speed systems.
TECH TIP: On the two speed systems, if there is a loss of communication with both actuators, the issue is more likely to be with the Fused Ignition Supply to the actuators since they share the same circuit. If the loss of communication is with only one of the actuators it would more likely be a ground issue or the actuator since they do not share the same ground. However, it is still possible to be missing the Fused Ignition Supply to only one actuator if the circuit issue is after the splice in the circuit.
- Verify that the battery or batteries are fully charged and the vehicle system voltage is correct. Diagnose any system voltage issues or DTCs before continuing with this diagnostic procedure.
- Using the wiring information as a guide, check the fuse that supplies the Fused Ignition Supply circuit for smart actuator(s). Verify the fuse is not open and has a good connection with the terminals in the PDC.
- If the fuse is good, continue testing in step 3.
- If the fuse is open, check the Fused Ignition Supply circuit and for a short to ground before replacing the fuse.
- Disconnect the smart actuator harness connector and check the Fused Ignition Supply and ground to the actuator.NOTE:
A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building the load test tool, additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .
- Load test the Fused Ignition Supply and ground circuits at the smart actuator harness connector. With the ignition on, connect one lead of the load test tool to the Fused Ignition Supply circuit and the other lead of the load test tool to the ground circuit. The load test bulb should be bright if both circuits are good. To verify that there is no resistance in the circuits being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. The voltage drop across the bulb should be equal to the voltage reading across the battery terminals if there is no resistance in either circuit.
- If the circuits fail the load test, remove the lead connected to the ground circuit and connect it to a good chassis ground. Check the voltage drop across the 3156 bulb of the load test tool again. If the voltage drop is still less than battery voltage, repair the Fused Ignition Supply circuit for an open or high resistance. If the voltage drop is now equal to battery voltage, repair the ground circuit for an open or high resistance.
- If the Fused Ignition Supply and ground circuits check good, continue testing in step 4.
- Load test the Fused Ignition Supply and ground circuits at the smart actuator harness connector. With the ignition on, connect one lead of the load test tool to the Fused Ignition Supply circuit and the other lead of the load test tool to the ground circuit. The load test bulb should be bright if both circuits are good. To verify that there is no resistance in the circuits being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. The voltage drop across the bulb should be equal to the voltage reading across the battery terminals if there is no resistance in either circuit.
- Check the Private CAN circuits between the smart actuator harness connector and the DTCM harness connector for a short to ground. Disconnect the smart actuator and DTCM harness connectors to isolate the circuits. Check both circuits for continuity to ground.
- If either circuit shows continuity to ground, repair the circuit for a short to ground and retest.
- If the circuits do not have continuity to ground, continue testing is step 5.
- Check the Private CAN circuits between the smart actuator harness connector and the DTCM harness connector for an open/high resistance. Measure the resistance of both CAN bus circuits between the smart actuator harness connector and the DTCM harness connector. The circuits should typically have less than 3.0 Ohms resistance.
- If either circuit has high resistance or is open, repair the circuit for an open or high resistance and retest.
- If the circuits have good continuity, and only one smart actuator has a loss of communication on a two speed system, replace the smart actuator in accordance with the service information. Clear all DTCs and retest the system for proper operation.
- If there is a loss of communication for both actuators on a two speed system and the wiring checks good, the Drivetrain Control Module is most likely faulty. Replace the Drivetrain Control Module in accordance with the service information. Use the scan tool and perform the Restore Vehicle Configuration procedure. Clear all DTCs and retest the system for proper operation. If the DTCs return, replace the smart actuators in accordance with the service information.
- If the wiring checks good on a one speed system, use the scan tool to check for other modules setting faults against the DTCM. If there are no other modules reporting loss of communication faults with the DTCM, replace the smart actuator in accordance with the service information. Clear all DTCs and retest the system for proper operation. If the DTC returns, replace the Drivetrain Control Module in accordance with the service information. Use the scan tool and perform the Restore Vehicle Configuration procedure.
- If there are other modules reporting loss of communication faults against the DTCM, replace the DTCM in accordance with the service information.
INTERNAL ECU AND MISMATCH DIAGNOSTICS (C1492-00, C1493-00, C2206-00, C2223-00):
- The C1492-00 and C1493-00 fault sets when a smart actuator is reporting an internal failure. Replace the smart actuator in accordance with the service information.
- The C2206-00 and C2223-00 mismatch faults can set if the wrong smart actuator is installed, or if the smart actuator or DTCM are replaced without the Restore Vehicle Configuration procedure being performed.
- Verify the correct smart actuator is installed on the vehicle.
- Use the scan tool to perform the Restore Vehicle Configuration procedure and retest for proper operation.
- If the fault returns, replace the Drivetrain Control Module in accordance with the service information. Use the scan tool and perform the Restore Vehicle Configuration procedure and retest for proper operation.