Circuit Description
The Controller Area Network (CAN) serial data line is a high speed serial data bus used to communicate information between the engine control module (ECM) and the transmission control module (TCM). Typical data-transmission speeds must be high enough to ensure that the required real-time response is maintained.
The CAN serial data line does not communicate with the scan tool via the DLC. CAN serial data information is interpreted by the ECM and transmitted to the serial data line by the ECM.
Conditions for Running the DTC
The diagnostic for this DTC is run when the ignition is cycled from OFF to RUN.
Conditions for Setting the DTC
The DTC is generated when the ECM is not calibrated to the vehicle.
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center, if equipped, may display a message. |
Conditions for Clearing the DTC
| • | A current DTC Last Test Failed clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Diagnostic Aids
The most likely occurrence of this DTC being set is due to incorrect calibration files downloaded to the ECM, or an ECM installed in the vehicle without the reprogramming procedure having been performed.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check Engine Controls? | Go to Step 2 | |
2 |
Does the DTC reset? | Go to Step 3 | Go to Step 4 |
3 |
Important: Perform the programming or set up procedure for the replaced control module if required. Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | Go to Step 4 | -- |
4 |
Does the DTC run and pass? | Go to Step 5 | Go to Step 2 |
5 | Observe the stored information, Capture Info, with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? | System OK |
