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.
Test Description
The numbers below refer to the step numbers in the diagnostic table.
- 2
Lack of communication may be due to partial or total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
- 4
The presence of DTCs that begin with a "U" indicates that some other module is not communicating. The specified procedure will compile all of the available information before tests are performed.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Install a scan tool. Does the scan tool power up? |
Go to Step 2 | Go to Scan Tool Does Not Power Up in Data Link Communications |
| 2 |
|
Go to Step 3 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications |
| 3 | Use the scan tool in order to display DTCs for the following control modules:
Does the scan tool display any DTCs for the control modules listed above? |
Go to Step 4 | Go to Symptoms - Antilock Brake System |
| 4 | Does the scan tool display any DTCs that begin with a "U", DTC C0290, C0292 or C0297? | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | Go to Step 5 |
| 5 | Does the scan tool display DTC P0500, P0502, P0503, P0562, P0563, P0601-P0607, P1381, P1621, P1627 or P1683? | Go to Diagnostic Trouble Code (DTC) List , in Engine Controls - 4.3L or Diagnostic Trouble Code (DTC) List , in Engine Controls - 4.8L, 5.3L, or 6.0L or Diagnostic Trouble Code (DTC) List , in Engine Controls - 6.6L or Diagnostic Trouble Code (DTC) List in Engine Controls - 8.1L | Go to Step 6 |
| 6 | Does the scan tool display DTC B1367? | Go to Diagnostic Trouble Code (DTC) List in Instrument Panel, Gauges, and Console | Go to Diagnostic Trouble Code (DTC) List |
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.