U0121 Honda Code - Lost Communication With Anti-Lock Brake System Control Module
Quick Answer
A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Faulty Anti-Lock Brake System (ABS) Control Module, Anti-Lock Brake System Control Module harness is open or shorted, Anti-Lock Brake System Control Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- U0121 Honda indicates Lost Communication With Anti-Lock Brake System Control Module .
- Common causes
- Common causes include Faulty Anti-Lock Brake System (ABS) Control Module, Anti-Lock Brake System Control Module harness is open or shorted, Anti-Lock Brake System Control Module circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code U0121 Honda Description
What are the Possible Causes of the DTC U0121 Honda?
- Faulty Anti-Lock Brake System (ABS) Control Module
- Anti-Lock Brake System Control Module harness is open or shorted
- Anti-Lock Brake System Control Module circuit poor electrical connection
How to Fix the DTC U0121 Honda?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the U0121 Honda code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about U0121 Honda Code
1. What does the OBDII code U0121 mean on a Honda?
U0121 indicates "Lost Communication With Anti-Lock Brake System (ABS) Control Module," meaning the vehicle's main control modules cannot communicate with the ABS module.
2. What are common symptoms of the U0121 code on a Honda?
Symptoms include the ABS warning light illuminating, loss of ABS functionality, traction control or stability control warnings, and inconsistent braking performance.
3. What causes the U0121 code on a Honda?
Common causes include a faulty ABS control module, damaged wiring or connectors, poor electrical connections, or a failing CAN bus network.
4. Can I still drive my Honda with the U0121 code?
While the vehicle may still be drivable, the ABS and related safety features may not function, increasing the risk of skidding or loss of control during braking.
5. How do I diagnose the U0121 code on a Honda?
Start by checking the ABS module’s wiring and connectors for damage or corrosion, inspect the CAN bus network for continuity, and ensure the ABS module is receiving power and ground.
6. How do I fix the U0121 code on my Honda?
Repairs may include replacing damaged wiring or connectors, repairing the CAN bus network, or replacing a faulty ABS control module.
7. How much does it cost to fix the U0121 code on a Honda?
The cost varies depending on the issue, ranging from $50 for minor wiring repairs to over $1,000 if the ABS module needs replacement.
8. Can a weak battery cause the U0121 code on a Honda?
Yes, a weak or failing battery can cause communication issues between modules, potentially triggering the U0121 code.
9. Can a U0121 code clear itself on a Honda?
In rare cases, the code may clear if the issue was temporary, but it often requires repairs and a diagnostic tool to reset the code.
10. Is the U0121 code related to other warning lights on a Honda?
Yes, the U0121 code often triggers additional warning lights, such as the ABS, traction control, or stability control lights.
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