Tire Pressure Monitoring

9020-CAN BUS OFF





For a complete wiring diagram Refer to Diagrams/Electrical Electrical Diagrams


- When Monitored:

Ignition on.

- Set Condition:

The TPM Module loses communication over the CAN Bus circuit. The circuit is continuously monitored.







Always perform the Engine Pre-Diagnostic Troubleshooting procedure before proceeding. Testing and Inspection


Refer to Manufacturer Trouble Codes for diagnostic procedures and for further possible causes.



Diagnostic Test


1. ACTIVE DTC


NOTE: Review the vehicle repair history. If the Electronic Ignition Switch/Central Gateway Module has been replaced, ensure that it has been programmed correctly.

Ignition on, engine not running.

With a scan tool, read DTCs.

Is the DTC active at this time?

Yes

- Go To 3

No

- Go To 2



2. INTERMITTENT CONDITION

NOTE: Check for any of the follow conditions:
- Poor wire to terminal connection
- Corroded terminals
- Backed out or loose terminals
- Broken wire internal to the insulation
- Dirty (partial) module ground


Were any of the above condition present?

Yes

- Repair as necessary.
- Perform TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test

No

DTC is not active at this time. Test complete.



3. OTHER COMMUNICATION DTC(S)

Using the scan tool, check other CAN B modules.

Are communication DTC(s) present?

Yes

- Refer to Manufacturers Trouble Codes and perform the applicable Diagnostic procedure.

No

- Go To 4



4. MEASURE VOLTAGE AT TPM MODULE

Turn the ignition on.

Gain access to the TPM Module harness connector, but do not disconnect.

Backprobe and measure the voltage on both the CAN B Bus (+) and the CAN B (-) circuits.


NOTE: With the BUS active, the voltmeter should read, CAN B Bus (-) 4.65 - 4.98 volts and CAN B Bus (+) 0.39 - 0.46 volts.

Does the voltmeter read the correct voltages?

Yes

- Replace the TPM Module.
- Perform TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test

No - CAN B Bus (-)

- Repair the open in the CAN B Bus (-).
- Perform TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test

No - CAN B Bus (+)

- Repair the open in the CAN B Bus (+)
- Perform TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test