Diagnostic Test
- CHECK IF THE MODULE IS ACTIVE ON THE BUS NOTE:
Check for any TSB(s) related to the condition. If a TSB applies, perform the procedure outlined in the TSB before continuing.
- Turn the ignition on.NOTE:
Make sure the battery voltage is between 10.0 and 16.0 volts.
NOTE:Check the fuse for both the (F921) Fused Ignition Run circuit. If the fuse is open, make sure to check for a short to ground and repair as necessary before proceeding.
NOTE:Check the BCM for any active CAN DTCs and perform the appropriate diagnostics before proceeding. Refer to DIAGNOSIS AND TESTING .
- With the scan tool, read the module status.
Does the scan tool indicate that the module is active on the bus?
Yes
- Refer to DIAGNOSIS AND TESTING and perform the STORED LOST COMMUNICATION DTCS diagnostic procedure.
No
- Go To 2
- Turn the ignition on.
- CHECK THE (F921) FUSED IGNITION RUN CIRCUIT FOR AN OPEN
- Turn the ignition off.
- Disconnect the Heated Seat Module C1 harness connector.
- Ignition on, engine running.NOTE:
If equipped with Stop-Start, the engine may not run but the circuit should be powered up.
- Using a 12-volt test light connected to ground, check the (F921) Fused Ignition Run circuit.NOTE:
The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Yes
- Go To 3
No
- Repair the (F921) Fused Ignition Run circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
- CHECK THE (Z909) GROUND CIRCUIT FOR AN OPEN
- Turn the ignition off.
- Using a 12-volt test light connected to 12-volts, check the (Z909) Ground circuit.
Does the test light illuminate brightly?
Yes
- Go To 4
No
- Repair the (Z909) Ground circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
- CHECK THE (D163) AND (D164) CAN INTERIOR BUS CIRCUITS FOR AN OPEN
- Disconnect the Star Can IHS Body harness connector.
- Measure the resistance of the (D164) CAN IHS Bus (-) circuit between the Star Can IHS Body harness connector and the Heated Seat Module C1 harness connector.
- Measure the resistance of the (D163) CAN IHS Bus (+) circuit between the Star Can IHS Body harness connector and the Heated Seat Module C1 harness connector.
Are the resistances below 5.0 Ohms?
Yes
- Replace the Heated Seat Module in accordance with the Service Information. Refer to MODULE, HEATED SEAT, REMOVAL .
- Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
No
- Repair the (D163) or (D164) CAN IHS Bus circuit for an open.
- Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .