U1439
Implausible/Missing Programmed Axle Ratio
U1439 is an OBD-II diagnostic trouble code meaning: Implausible/Missing Programmed Axle Ratio. Common causes: replacing a differential without reprogramming, installation of wheels of non-standard diameter. Estimated repair cost: ~$167.
Symptoms
- Incorrect gear shifting
- Check Engine Light Is On
- Decreased fuel efficiency
- Errors in the operation of the stabilization system
- Unusual cruise control behavior
Causes
- Replacing a differential without reprogramming
- Installation of wheels of non-standard diameter
- PCM software error
- Problems with wheel speed sensors
- Wiring harness fault
How to Fix
- Check the size of the installed wheels
- Read real gear ratio data
- Reprogram the PCM
- Check wheel speed sensors and their wiring
- Update control module software
Related codes
FAQ
What does the U1439 code mean?
U1439 is an OBD-II diagnostic trouble code that indicates: Implausible/Missing Programmed Axle Ratio
What causes a U1439 error code?
The most common causes of U1439 include: Replacing a differential without reprogramming; Installation of wheels of non-standard diameter; PCM software error; Problems with wheel speed sensors.
How do I fix a U1439 diagnostic trouble code?
To fix U1439: Check the size of the installed wheels. Read real gear ratio data. Reprogram the PCM. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U1439?
Yes, but get it checked soon
How much does it cost to fix U1439?
The estimated repair cost for U1439 is ~$167. Actual cost depends on your vehicle, location, and labor rates.
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