This diagnostic will detect a loss of serial communication from the electronic brake control module (EBCM) to the control module. This serial communication is essential in order to distinguish misfire from a rough road condition.
| • | The vehicle speed is 2 km/h (1 mph). | 
| • | The engine speed is less than 5800 RPM. | 
| • | The engine load is less than 89 percent. | 
| • | Engine misfire is detected. | 
A serial data malfunction is preventing the VCM from receiving rough road detection data.
| • | The control module stores the DTC in history after the first failure but will not illuminate the malfunction indicator lamp (MIL). | 
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores the failure information in the scan tools Freeze Frame/Failure Records. | 
| • | A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. | 
| • | A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle. | 
| • | Use the scan tool Clear Information function. | 
Check for the following conditions:
An intermittent may be caused by any of the following conditions:
| • | A poor connection | 
| • | Rubbed through wire insulation | 
| • | A broken wire inside the insulation | 
Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
The numbers below refer to the step numbers on the diagnostic table.
Step  | Action  | Values  | Yes  | No  | 
|---|---|---|---|---|
1  | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?  | --  | Go to Step 2  | |
2  | Check for any U-Codes. Did you find any U-Codes?  | --  | Go to the applicable DTC table  | Go to Step 3  | 
 Did you find a problem?  | --  | Go to Step 4  | Go to Diagnostic System Check in Antilock Brake System  | |
4  | Repair the circuit as necessary. Refer to Wiring Repairs or Connector Repairs in Wiring Systems. Is the action complete?  | --  | Go to Step 5  | --  | 
5  | 
 Does the scan tool indicate the diagnostic Passed?  | --  | Go to Step 6  | Go to Step 2  | 
6  | Does the scan tool display any additional undiagnosed DTCs?  | --  | Go to the applicable DTC table  | System OK  |