Pinpoint Test G : U0121:87: 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.
U0121:87
Refer to Wiring Diagram Vehicle Dynamic Systems for schematic and connector information.
Normal Operation and Fault Conditions
With the ignition ON, the ABS module sends messages to the VDM over the HS-CAN2. If the VDM does not receive these messages within a certain time frame, the module sets Diagnostic Trouble Codes (DTCs). For information on the messages sent to the VDM by the ABS module, go to the Network Message Chart. REFER to: Vehicle Dynamic Suspension - System Operation and Component Description .
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| U0121:87 | Lost Communication With Anti-Lock Brake System (ABS) Control Module: Missing Message | This DTC sets in continuous memory if any one of the following messages is missing: ABS active, brake torque request, stability control mode, stability control indicator request, traction control mode, vehicle lateral acceleration, vehicle longitudinal acceleration, vehicle roll rate or vehicle vertical acceleration. This can be due to a ABS module failure, a circuit failure on the ABS module or an excessive load on the network. |
Possible Sources
- Wiring, terminals or connectors
- Network communication concern
- Vehicle battery
- Charging system concern
- ABS module