Pinpoint Test I : Lost Communication With The Pcm (Powertrain Control Module): Notes
WARNING: This page is about a different car, the 2015 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
Refer to Vehicle Dynamic Systems for schematic and connector information.
NOTE:
The TCM and the differential control module - rear are both internal components of the PCM.
Normal Operation and Fault Conditions
With the ignition ON, the PCM sends messages to the ABS module over the HS-CAN. If the ABS module does not receive these messages within the specified time frame, the ABS module sets Diagnostic Trouble Codes (DTCs). This can be due to a PCM failure, a circuit failure on the HS-CAN or an excessive load on the network. For information on the messages sent to the ABS module by the PCM, TCM and differential control module - rear, REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description .
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| C0040:87 | Brake Pedal Switch "A": Missing Message | This DTC sets in continuous memory and on-demand if the brake pedal position message is missing for more than 500 ms. This can be due to a PCM failure, a stoplamp switch failure, a circuit failure on the HS-CAN or an excessive load on the network. |
| U0100:00 | Lost Communication With ECM/PCM "A": No Sub Type Information | This DTC sets in continuous memory and on-demand if any one of the following messages is missing; brake pedal position, cruise control status, power pack status or reverse gear. This can be due to a PCM failure, a circuit failure on the HS-CAN or an excessive load on the network. |
| U0101:00 | Lost Communication With TCM: No Sub Type Information | This DTC sets in continuous memory and on-demand if the selector lever (PRNDL) status message is missing. |
| U0136:00 | Lost Communication With Differential Control Module - Rear: No Sub Type Information | This DTC sets in continuous memory and on-demand if the all-wheel drive lock status message is missing. |
| U0437:68 | Invalid Data Received From Differential Control Module - Rear: Event Information | This DTC sets in continuous memory and on-demand if the all-wheel drive lock status message contains incorrect information. |
Possible Causes
- Network communication concern
- PCM
- ABS module