Heated Seat and Mirror Memory Module - False DTC's

NO: 08-23-98

GROUP: Electrical

DATE: May 22, 1998

SUBJECT:
Memory Heated Seat &
Mirror Module Erroneous
Diagnostic Trouble Code

MODELS:

1999 (LH) LHS/300M

SYMPTOM/CONDITION:

When the M1 fuse is pulled out or blown with the ignition in the "ON" position, and the ignition is then turned off, the Memory Heated Seats & Mirror Module (MHSMM) does not receive an ignition "OFF" message from the Body Control Module (BCM), This will set four erroneous faults in the process. Memory recall will also be disabled until a good M1 fuse has been reinstalled or the ignition is turned to the "ON" position.

DISCUSSION:

The four faults set by the MHSMM, as read with a DRB III(R), will be the "Ignition Status Fault," the "PRNDL Message Fault, and both "Left and Right Seat Output Shorted Fault." All are due to the lack of bus communication from the BCM to the MHSMM when the M1 fuse is not present or blown. To correct this condition, perform the following steps:

1. Verify that there is a good Mi fuse installed and functional.

2. Clear all MHSMM DTC's.

3. Start the vehicle and let run for one minute and check if any of the above four DTC's have been set in the MHSMM.

4. If any of the above DTC's are present, or any other non-related DTC's have been set, follow the repair procedure outlined in the 1999 LHS/300M service manual (Publication No. 81-270-8140A) section 8R and 8N and the 1998 Concorde/Intrepid, 1999 LHS/300M body diagnostic procedure's manual (Publication No. 81-699-97229).

5. If no DTC's have been set, verify memory recall and heater operation with the ignition "ON."

POLICY: Information Only