Diagnostic Test

1) CHECK FOR ACTIVE DTC
Press and release the switch three times.

Turn the ignition on.

With the scan tool, record and erase Instrument Cluster DTCs.

Turn the ignition off.

Turn the ignition on.

Wait 30 seconds.

With the scan tool, read Instrument Cluster DTCs.

Is DTC: B1243-REAR PARK ASSIST DISABLE SWITCH STUCK active?

Yes
1. Go To 2).
No
1. The condition that caused this code to set is not present at this time. Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals.
2. Perform BODY VERIFICATION TEST - VER 1 .
2) CHECK OPERATION OF THE LOWER SWITCH BANK

Fig 1: Checking Lower Switch Bank
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Lower Switch Bank Harness Connector.

Turn the ignition on.

Wait 30 seconds.

With the scan tool, read Instrument Cluster DTCs.

Does the scan tool display: B1243-REAR PARK ASSIST DISABLE SWITCH STUCK?

Yes
1. Go To 3).
No
1. Replace the Lower Switch Bank in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST - VER 1 .
3) CHECK THE (X774) PARK ASSIST ON/OFF SWITCH CIRCUIT FOR A SHORT TO GROUND

Fig 2: Checking Park Assist On/Off Switch Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Instrument Cluster C1 harness connector.

Measure the resistance of the (X774) Park Assist ON/OFF Switch circuit for a short to ground.

Is the resistance below 10K ohms?

Yes
1. Repair the (X774) Park Assist ON/OFF Switch circuit for a short to ground.
2. Perform BODY VERIFICATION TEST - VER 1 .
No
1. Replace the Instrument Cluster in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST - VER 1 .