U1821
Lost Communication With 14V Power Module On Powertrain Expansion Communication Bus
U1821 is an OBD-II diagnostic trouble code meaning: Lost Communication With 14V Power Module On Powertrain Expansion Communication Bus. Common causes: open or short circuit in the communication circuit, 14v power module faulty. Estimated repair cost: $56–167.
Symptoms
- Check Engine light comes on
- There may be problems with the operation of the car's electronic systems
- Reduced engine power
- Unstable engine operation
- Errors in other vehicle systems
Causes
- Open or short circuit in the communication circuit
- 14V power module faulty
- Power Train Expansion Bus Problems
- Poor contact in connectors
- Module power problems
How to Fix
- Check the integrity of the wiring harness and connectors
- Check the power and ground of the 14V power module
- Check the condition of the power train extension bus
- Scan other modules for errors
- If necessary, replace the 14V power module
Related codes
FAQ
What does the U1821 code mean?
U1821 is an OBD-II diagnostic trouble code that indicates: Lost Communication With 14V Power Module On Powertrain Expansion Communication Bus
What causes a U1821 error code?
The most common causes of U1821 include: Open or short circuit in the communication circuit; 14V power module faulty; Power Train Expansion Bus Problems; Poor contact in connectors.
How do I fix a U1821 diagnostic trouble code?
To fix U1821: Check the integrity of the wiring harness and connectors. Check the power and ground of the 14V power module. Check the condition of the power train extension bus. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U1821?
Yes, but get it checked soon
How much does it cost to fix U1821?
The estimated repair cost for U1821 is $56–167. Actual cost depends on your vehicle, location, and labor rates.
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