What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
U0121-00Lost Communication With Anti-lock Brake System (ABS) Control ModuleU0121-00Lost Communication With Anti-Lock Brake System (ABS) Control ModuleU0121LOSS OF COMMUNICATION WITH EBCMU0121LOSS OF COMMUNICATION WITH EBCMView all · Manufacturer wording →
Manufacturer communications
62Original wording in English
CHRYSLER
Reported code forms U0121-00
Flash: Anti-Lock Brakes (ABS) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Code (DTC): ●…
CHRYSLER
Reported code forms U0121-00
Flash: Anti-Lock Brakes (ABS) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ●…
JEEP
Reported code forms U0121-00
Not applicable to vehicles built for US market. Multiple Systems Repair Bundle Campaign Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the…
CHRYSLER
Reported code forms U0121 U0121-00
Vehicle Will Not Shift From Park. Antilock Brake System (ABS) Light On In Cluster. U0121, U1110, U120C Diagnostic Trouble Codes (DTCs) Set. Discussion: If a vehicle has a complaint of will not shift from park and the…
FORD
Reported code forms U0121
This article supersedes TSB 21-2405 to update the production fix date. Some of the vehicles listed in the Model statement above may exhibit all of the following conditions: * Illuminated powertrain malfunction indicator…
AUDI
Reported code forms U012100
This bulletin provide sinformation when the ABS/ESC Control unit cannot be reached; DTC U012100 "ABS Control Module no communication."
Check vehicle applicability
796A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Audi | A4 | 2010 |
| Audi | A4 | 2009 |
| Audi | A4 ALLROAD | 2014 |
| Audi | A4 ALLROAD | 2013 |
| Audi | A4 AVANT | 2012 |
| Audi | A4 AVANT | 2011 |
| Audi | A5 | 2014 |
| Audi | A5 | 2013 |
| Audi | A5 | 2012 |
| Audi | A5 | 2011 |
| Audi | A5 | 2010 |
| Audi | A5 | 2009 |
Historical records · 243 · Historical vehicle association; OBD-II compatibility is not established by this record.
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.