Circuit Description
The PZM commands the Daytime Running Lamps (DRL) ON or OFF through a discrete output to the DRL relay. The DRL is only active under the following conditions:
| • | The ignition is in the RUN or START position. |
| • | The twilight sentinel is not active. |
| • | The headlamps (low and high beam) and foglamps are OFF. |
| • | The transmission is not in PARK. |
When the relay is energized, the relay places the high beams in a series circuit, providing lower illumination for the DRL.
A short to ground is tested under the following conditions:
| • | Ignition 1 is ON. |
| • | The DRL is inactive. |
| • | The instrument cluster verifies that the vehicle has DRL. |
A short to battery will be tested under the following conditions:
| • | Ignition 1 is OFF or both ignition 1 DRLs are active. |
| • | The instrument cluster verifies that the vehicle has DRL. |
Conditions for Setting the DTC
The commanded state of the DRL does not match the feedback.
Action Taken When the DTC Sets
The PZM continues to command the state requested until the state is achieved or changes.
Conditions for Clearing the DTC
The commanded state matches the feedback state for 2 consecutive monitoring cycles.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Lighting System Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Is battery voltage measured? | -- | Go to Step 3 | Go to Step 5 |
3 |
Do the DRLs turn on? | -- | Go to Step 4 | Go to Step 6 |
4 | Replace the PZM. Refer to Body Control Module Replacement in Body Control Systems. Is the repair complete? | -- | Go to Step 9 | -- |
5 | Repair the open or short to ground in CKT 439 (PNK). Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 9 | -- |
6 | Inspect CKT 592 (LT GRN/BLK) for an open. Refer to Testing for Continuity in Wiring Systems. Is CKT 592 OK? | -- | Go to Step 7 | Go to Step 8 |
7 | Replace the DRL relay. Is the repair complete? | -- | Go to Step 9 | -- |
8 | Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK. |
