Transmission Cooler Bypass Valve Stuck Open
The P2948 code means the vehicle's onboard diagnostic system has detected: Transmission Cooler Bypass Valve Stuck Open. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $300 - $1,200 (parts and labor)
Read and clear transmission codes. Many trans codes are caused by low or burnt fluid -- check level and color before assuming the worst.
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Basic scanners only read engine codes. This reads transmission, ABS, and airbag too.
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Common Symptoms
- Transmission overheating warning
- Reduced shift quality when hot
- Check Engine Light on
- Transmission fluid discoloration
Probable Causes (Ranked by Likelihood)
- Transmission cooler clogged or restricted Very High
- Cooler bypass valve malfunction High
- Coolant system issue affecting trans cooler Moderate
- Temperature sensor inaccuracy Low
Step-by-Step Diagnostic Procedure
-
Check transmission fluid temperature
-
Test cooler flow rate
-
Inspect cooler lines for restriction
-
Verify temperature sensor readings
Frequently Asked Questions
Is this a serious problem?
This is a moderate concern that should be addressed soon to prevent further damage.
Can a fluid change help?
A fluid change is unlikely to resolve this specific issue, though it should be part of any transmission service.
How much does repair cost?
Typical repair costs range from $300 - $1,200 depending on the specific cause and vehicle.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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