Central Control Module (CCM)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

CKT 149 is used to complete the electrical circuit for the courtesy lamp system. CKT 149 is grounded by the CCM when the CCM gets a request to activate the roof rail and door courtesy lamps.

DTC WILL SET WHEN

This flat will only set if the courtesy output is "OFF" (CCM not grounding CKT 149) and the DIL relay has been enabled to come "ON." If the fault lasts longer than 2 seconds, DTC 25 will set because voltage at terminal "C12" should be "high" if the courtesy output is "OFF."

ACTION TAKEN

DTC 25 will set. If CKT 149 is shorted to ground, the courtesy lamps will be "ON" until illuminated entry, or delay interior lamps time out. If CKT 149 is open, the courtesy lamps will be "OFF" at all times.

DTC WILL CLEAR WHEN

DTC 25 will clear if the fault goes away for 2 or more seconds.

DTC CHART TEST DESCRIPTION

Number(s) below refer to circled number(s) on the diagnostic chart.

1. mis test checks to see if courtesy lamp system is functioning.

2. This test checks for a defective CCM or short to ground in CKT 149.

3. This test checks I/P fuse 27.

4. This test measures CKT 149 voltage at CCM "C2" connector terminal "C12".

5. This test checks for B+ at DIL relay terminal

6. This test checks to see if voltage is going out to CKT 823.

DIAGNOSTIC AIDS

If the DTC is a history DTC, the problem may be intermittent. Try performing the test shown while "wiggling" wiring and connectors; this can often cause the fault to appear. Check for poor connections at both the CCM and the delayed interior lamp relay connector; these could cause an open or an intermittent fault. Refer to "Intermittents/History DTCs". Intermittents/History DTCs

If following trouble trees for test 3 in diagnostic chart, make sure ignition is "OFF" and CCM has gone to sleep before checking for short to ground in CKTs 740/823.

A Tech 1 can be used to activate the DIL relay.