PINPOINT TEST T : DTCs U0028:08 AND U0028:88: Notes
Diagnostic Overview
Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices. Refer to Diagnostic Methods in Service Information for information about these practices.
Refer to Vehicle Dynamic Systems , for schematic and connector information.
Normal Operation and Fault Conditions
The RCM supplies the stability/traction control system with the yaw rate, roll rate, lateral and longitudinal accelerometer data over a dedicated CAN. If the RCM detects a fault with communications with the ABS module or dedicated CAN bus circuits, it sets DTC U0028:08 or U0028:88.
The RCM does not request the IPC to illuminate the airbag warning indicator if either DTC U0028:08 or U0028:88 is set.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| U0028:08 | Vehicle Communication Bus A: Bus Signal / Message Failures | A fault is indicted when the RCM does not receive messages from the ABS module on the dedicated CAN bus for 5 seconds. An open dedicated CAN circuit, incorrectly installed ABS module or loss of power and/or ground to the ABS module can set this DTC. |
| U0028:88 | Vehicle Communication Bus A: Bus Off | A fault is indicted when the RCM detects the dedicated CAN circuits are shorted to ground, shorted to voltage or shorted to each other. |
Possible Sources
- Wiring, terminals or connectors
- RCM
- ABS module
Visual Inspection and Diagnostic Pre-checks
- Inspect for damaged wiring harness(es).
- Inspect for a loose or damaged ABS module connector.