U0025-CAN B BUS (-) CIRCUIT LOW
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
Continuously.
- Set Condition:
The TIPM detects the (D54) CAN B Bus (-) circuit is shorted to ground.
| Possible Causes |
| (D54) CAN B BUS (-) CIRCUIT SHORTED TO GROUND OR TO (D55) CAN B BUS (+) CIRCUIT |
| ANY CAN B BUS MODULE |
| TOTALLY INTEGRATED POWER MODULE |
Diagnostic Test
1. TEST FOR INTERMITTENT CONDITIONNOTE: Check for any TSB(s) related to the condition. If a TSB applies, perform the procedure outlined in the TSB before continuing.
Turn the ignition on.
With the scan tool, record and erase TIPM DTC's.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read active TIPM DTC's.
Does the scan tool display this DTC as active?
Yes
- Go To 2
No
- 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 (D54) CAN B BUS (-) CIRCUIT FOR A SHORT TO GROUND
Turn the ignition off.
Disconnect the Totally Integrated Power Module C3 harness connector.
Measure the resistance between ground and the (D54) CAN B Bus (-) circuit.
Is resistance below 1000.0 ohms?
Yes
- Go To 3
No
- Go To 4
3. (D54) CAN B BUS (-) CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (D54) 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 circuit is shorted to ground internally within a module or if the circuit is shorted to ground in the harness.
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 wring diagrams to assist in diagnosis.
Is resistance below 1000.0 ohms with all the CAN B Bus modules disconnected?
Yes
- Repair the (D54) CAN B Bus (-) circuit for a short to ground.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Replace the module that when disconnected eliminated the short to ground in accordance with the service information.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
4. CHECK THE (D55) CAN B BUS (+) CIRCUIT FOR A SHORT TO THE (D54) CAN B BUS (-) CIRCUIT
Measure the resistance between the (D55) CAN B Bus (+) circuit and (D54) CAN B Bus (-) circuit.
Is resistance below 1000.0 ohms?
Yes
- Go To 5
No
- Inspect the wiring and connectors for damage or shorted circuits. If ok, replace the Totally Integrated Power Module in accordance with the service information.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
5. (D55) CAN B BUS (+) CIRCUIT SHORTED TO THE (D54) CAN B BUS (-) CIRCUIT
Measure the resistance between the (D55) CAN B Bus (+) circuit and (D54) 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 together is internal within a module or if the circuits are shorted together.
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 wring 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 the (D54) CAN B Bus (-) circuit.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Replace the module that when disconnected the short together was eliminated, in accordance with the service information.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).