Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Test
- CHECK FOR AN ACTIVE DTC NOTE:
If the scan tool will not communicate with CAN C, proceed to SCAN TOOL DOES NOT COMMUNICATE WITH CAN C. Refer to COMMUNICATION, NON-DTC BASED DIAGNOSTICS .
- With the scan tool, run a Vehicle Scan Report and attached it to the repair order.
- With the scan tool, erase DTCs.
- Using the Vehicle Scan Report, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Proceed to SCAN TOOL DOES NOT COMMUNICATE WITH CAN C. Refer to COMMUNICATION, NON-DTC BASED DIAGNOSTICS .
No
- Go To 2
- ATTEMPT TO LOCATE AN INTERMITTENT CIRCUIT FAULT NOTE:
The scan tool LOSS OF COMM TEST will force the modules on the CAN C bus to continuously ping each other.
- With the scan tool, initiate the LOSS OF COMM TEST.NOTE:
A value above 0 under the NUMBER OF NO RESPONSES can help indicate the location of a circuit fault while wiggling the related CAN C bus circuits.
- With the scan tool, initiate the LOSS OF COMM TEST.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.