Pinpoint Test H : DTC U0121: Notes
WARNING: This page is about a different car, the 2018 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.
| Refer to Wiring Diagram
for schematic and connector information. Normal Operation and Fault Conditions The TCM sets the DTC U0121 when key messages such as wheel speed, brake pressure or torque are not received for longer than 5 seconds. This loss of key messages degrades the transmission functionality. Other modules that require data from the ABS module all set communication DTCs and may also exhibit system function concerns. DTC Fault Trigger Conditions |
|---|
| DTC | Description | Fault Trigger Condition |
|---|---|---|
| TCM U0121:00 | Lost Communication With Anti-Lock Brake System (ABS) Control Module "A": No Sub Type Information | Sets in continuous memory in the TCM if ABS data messages received from the ABS module over the HS-CAN are missing for longer than 5 seconds. |
Possible Sources
Communication concern
Battery voltage concern
ABS
TCM