Diagnostic Test

WARNING: This page is about a different car, the 2006 Dodge Magnum, 2006 Dodge Charger, and 2006 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

1) VERIFY DTC U0019-CAN B BUS IS ACTIVE
Turn the ignition on.

With the scan tool, read HVAC DTCs.

Does the scan tool display active: U0019-CAN B BUS?

Yes
1. Go To 2).
No
1. If the DTC is stored, 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. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
2) CHECK FOR ACTIVE CAN B BUS RELATED DTCS IN THE FRONT CONTROL MODULE (FCM)
With the scan tool, read Front Control Module (FCM) DTCs

Does the scan tool display any active CAN B BUS related DTCs?

Yes
1. Diagnose and repair the DTC(s). (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING) .
No
1. Go To 3).
3) CHECK (D55) CAN B BUS (+) CIRCUIT FOR AN OPEN

Fig 1: Checking CAN B Bus (+) Circuit For Open
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the negative battery cable.

Disconnect the A/C Heater Control C1 harness connector.

Disconnect the Front Control Module (FCM) C1 harness connector.

Measure the resistance of the (D55) CAN B Bus (+) circuit between the Front Control Module C1 harness connector and the A/C Heater Control C1 harness connector.

Is the resistance below 2.0 ohms?

Yes
1. Go To 4).
No
1. Repair the (D55) CAN B Bus (+) circuit for an open.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
4) CHECK (D54) CAN B BUS (-) CIRCUIT FOR AN OPEN

Fig 2: Checking CAN B Bus (-) Circuit For Open
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance of the (D54) CAN B Bus (-) circuit between the Front Control Module C1 connector and the A/C Heater Control C1 harness connector.

Is the resistance below 2.0 ohms?

Yes
1. Replace the A/C Heater Control in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
No
1. Repair the (D54) CAN B Bus (-) circuit for an open.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .