Tire Pressure Monitoring

9020-CAN BUS OFF





For a complete wiring diagram Consult Diagrams/Electrical.

- When Monitored:
Ignition on.

- Set Condition:
The TPM Module loses communication over the CAN Bus circuit. The circuit is continuously monitored.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview.

Refer to Communications Test for this DTC and/or Manufacturer Code Charts 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

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

- Diagnose and repair the DTC(s).

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

No - CAN B Bus (-)

- Repair the open in the CAN B Bus (-).
- Perform TPM VERIFICATION TEST

No - CAN B Bus (+)

- Repair the open in the CAN B Bus (+)
- Perform TPM VERIFICATION TEST