Central Control Module (CCM)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The headlights relay coil circuit is part of the headlight system. The CCM is able to control the headlights via CKT 691. In addition to the CCM control of the headlights, the headlights can also be turned "ON" by grounding CKT 691 at the keyless entry receiver/UTD and or the headlight switch.

TEST CONDITIONS

This fault will only set when the CCM commands the headlights "ON."

FAILURE CONDITIONS

DTC 34 will set when the headlamp enable stays near battery voltage when the CCM is trying to take it to ground to enable the headlights to come "ON."

TEST DESCRIPTION

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

1. This test checks for a short to B+ in CKT 691.

2. This test checks for an internal short in the relay between terminals "E3" and "E2", which would cause a short to battery condition.

3. This test checks for an internal short in the relay coil.

4. This test checks if problem is in headlight switch.

5. This test checks if problem is in Remote Keyless Entry/Universal Theft Deterrent (RKE/UTD) receiver.

DIAGNOSTIC AIDS

Do not turn the headlamp switch "ON" while DTC 34 is current. The headlamp switch may short out due to excessive current flow in CKT 691.

If the DTC is a history code, the problem may be intermittent. Try performing the test shown while "wiggling" wiring and connectors; this can often cause the fault to appear. Refer to "Intermittents/History Codes/Poor Connections". Intermittents/History DTCs

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