U0022-CAN B BUS (+) CIRCUIT LOW

For a complete wiring diagram Refer to Section 8W.

When Monitored:
Continuously.
Set Condition:
The FCM detects the (D55) CAN B Bus (+) circuit is shorted to ground.

(D55) CAN B BUS (+) CIRCUIT SHORTED TO GROUND

Diagnostic Test

Turn the ignition on.
With the scan tool, record and erase FCM DTC's.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read active FCM DTC's.

Does the scan tool display this DTC as active?

Yes

Go To 2

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. CHECK THE (D55) CAN B BUS (+) CIRCUIT FOR A SHORT TO GROUND

Turn the ignition off.
Disconnect the Front Control Module C1 harness connector.
Measure the resistance between ground and the (D55) CAN B Bus (+) circuit.

Is resistance below 1000.0 ohms?

Yes

Go To 3

Inspect the wiring and connectors for damage or shorted circuits. If ok, replace the Front Control Module in accordance with the service information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

3. (D55) CAN B BUS (+) CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (D55) CAN B Bus (+) circuit.
While monitoring the ohmmeter, disconnect each CAN B Bus module one at a time.

NOTE: This is to determine if the short to ground is internal within a module or if the circuit is shorted.

NOTE: Disconnecting an in-line connector can eliminate a module or group of modules from the list of possible causes for this fault. Refer to the wiring diagrams to assist in diagnosis.

Is resistance below 1000.0 ohms with all the CAN B Bus modules disconnected?

Yes

Repair the (D55) CAN B Bus (+) circuit for a short to ground.

Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

Replace the module that when disconnected the short to ground was eliminated, in accordance with the service information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).