Diagnostic Test

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

1) TEST FOR INTERMITTENT CONDITION
With the scan tool, record and erase DTC's

Operate the door locks several times.

Cycle the ignition from on to off.

Turn the ignition on.

With the scan tool, read DTC's.

Does the scan tool display ALL DOOR LOCK RELAY CONTROL CIRCUIT HIGH?

Yes
1. Go To step 2).
No
1. The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
2. Perform BODY VERIFICATION TEST - VER 1 .
2) DOOR LOCK RELAY SHORTED TO BATTERY

Fig 1: Checking Door Lock Relay Circuit For Short To Battery
Courtesy of DAIMLERCHRYSLER CORP.

NOTE: Ensure the doors are unlocked and the windows down before proceeding.

Turn the ignition off.

Disconnect the Cluster C2 connector.

Momentarily connect a jumper wire between the (P777) Door Lock Relay Control circuit and the (Z905) Ground circuit in the Cluster C2 connector.

Did the doors lock?

Yes
1. Replace the Instrument Cluster in accordance with service information.
2. Perform BODY VERIFICATION TEST - VER 1 .
No
1. Go To step 3).
3) (P777) DOOR LOCK RELAY CONTROL CIRCUIT SHORTED TO BATTERY

Fig 2: Checking (P777) Door Lock Relay Control Circuit For Short To Battery
Courtesy of DAIMLERCHRYSLER CORP.

Disconnect the Junction Block C2 connector (on top of junction block).

Measure the voltage between ground and the (P777) Door Lock Relay Control circuit in the Cluster C2 connector.

Turn the ignition on.

Is there any voltage present?

Yes
1. Repair the (P777) Door Lock Relay Control circuit for a short to voltage.
2. Perform BODY VERIFICATION TEST - VER 1 .
No
1. Replace the Junction Block in accordance with service information.
2. Perform BODY VERIFICATION TEST - VER 1 .