Entering BCM Diagnostics
To enter the self-test mode and retrieve DTCs from the body control
module (BCM), perform the following:
- Make sure the ignition switch is OFF.
- Make sure that the hood, trunk and all doors are closed.
- Turn the instrument panel dimmer switch to OFF.
- Remove the fuse labeled MALL PGM.
- Turn the ignition switch from OFF to ACC.
• | The BCM will sound the type number of the BCM on the chime generator.
(2 through 4) Check to see if the BCM type number matches the option codes
for the vehicle. |
- | Base vehicle -- BCM type 2 |
- | RPO AU0 and UA6 -- BCM type 4 |
- Turn the ignition from ACC to OFF and back to ACC, taking no more
that 1 second to complete the action.
• | The BCM now flashes the seat belt indicator and sounds the chime
to indicate the stored DTCs in the BCM. |
• | The BCM reports the stored DTCs in numerical order from the lowest
to the highest. |
• | The BCM repeats the series of stored DTCs three times. |
• | If the BCM does not flash the seat belt indicator or sound the
chime, there are no DTCs stored. |
Clearing DTCs
- Make sure the BCM is in self-test and you have retrieved DTCs.
- Press and hold the door UNLOCK switch on either front door for
4 seconds.
Input Testing
- Make sure the BCM is in self-test and you have retrieved DTCs.
• | The BCM enters the input test mode after it repeats the DTC series
for the third time. |
• | If no DTCs are stored, the BCM enters this mode immediately. |
- The BCM sounds the chime and flashes the seat belts indicator
once for each activation of the following inputs:
• | The reading lamp switches |
• | The door lock cylinders |
• | The driver seat belt switch |
• | The interior door lock switches |
• | The driver information display switches |
• | The IP compartment lamp switch |
• | The rear compartment lamp switch |
• | The sunshade illuminated mirrors |
• | The trip calculator switches |
• | The keyless entry requests for lock/unlock |
- If the BCM does not sound the chime and illuminate the seat belt
indicator when an input is activated, the input circuit is malfunctioning.
Refer to the affected subsystem diagnostic system check.
Output Testing
- Make sure the BCM is in self-test and you have retrieved DTCs.
- Turn the IP dimmer switch to the DOME position to begin the first
output test.
- Turn the IP dimmer switch from DOME to OFF and back to DOME to
step through the 7 tests listed:
• | Test 1 - turns OFF all interior lamps |
• | Test 2 - turns ON the interior lamps |
• | Test 3 - turns ON all courtesy lamps |
• | Test 4 - energizes the theft deterrent relay for 1 second
and turns ON the headlamps, for BCM Type 4 only |
• | Test 5 - energizes the horn relay for 25 ms and turns
ON the horn, for BCM Type 4 only |
• | Test 6 - turns ON the theft deterrent indicator lamp, for
BCM Type 4 only |
• | Test 7- turns OFF the theft deterrent indicator
lamp, for BCM Type 4 only |
- The BCM sounds the chime to indicate the output test number.
- Once all tests are completed, the cycle will repeat with each
DOME-OFF-DOME cycle of the IP dimmer switch.
Remember that the
maximum number of output tests for Type 2 and Type 3 BCMs is
3.
Exiting Diagnostics
Perform the following to return to normal operation of the BCM:
- Turn the ignition switch to the OFF position.
- Install the MALL PGM fuse.
- Turn the ignition switch to the RUN position.