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) CHECK FOR ACTIVE DTCS
With the scan tool, read the active SCM DTC's.

Cycle the ignition switch from off to on at least 5 times, leaving the ignition on for a minimum of 90 seconds per cycle.

With the scan tool, read the active SCM DTC's.

Does the scan tool display this DTC as active?

Yes
1. Go To step 2).
No
1. If the DTC is stored, check for an intermittent condition. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
2) CHECK FRONT CONTROL MODULE DTC's
With the scan tool, read Front Control Module active DTC's

Does the scan tool display any CAN C BUS DTC's - ACTIVE?

Yes
1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING)
No
1. Go To step 3).
3) (D65) CAN C BUS (+) CIRCUIT OPEN

Fig 1: Can C Bus (+) Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the negative battery cable.

Disconnect the Steering Column Module C1 harness connector.

Disconnect the Front Control Module C1 connector.

Measure the resistance of the (D65) CAN C Bus (+) circuit between the Front Control Module connector and the Steering Column Module connector.

Is the resistance below 2.0 ohms?

Yes
1. Go To step 4).
No
1. Repair the (D65) CAN C Bus (+) circuit for an open.
4) (D64) CAN C BUS (-) CIRCUIT OPEN

Fig 2: Can C Bus (-) Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance of the (D64) CAN C Bus (-) circuit between the Front Control Module connector and the Steering Column Module connector.

Is the resistance below 2.0 ohms?

Yes
1. Replace the Steering Column Module in accordance with the service information.
No
1. Repair the (D64) CAN C Bus (-) circuit for an open.