Transmission Fluid Pressure Sensor/Switch B Circuit High
The P0848 code means the vehicle's onboard diagnostic system has detected: Transmission Fluid Pressure Sensor/Switch B Circuit High. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $100 - $500 (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
- Check Engine Light illuminated
- Firm or harsh shifts
- Transmission may not shift smoothly
- Possible limp mode
Probable Causes (Ranked by Likelihood)
- Open ground wire at pressure sensor B Very High
- Faulty pressure sensor B stuck high High
- Short to voltage in sensor B signal wire Moderate
- TCM reference voltage problem Low
Step-by-Step Diagnostic Procedure
-
Measure voltage at pressure sensor B connector with key on
-
Check for an open ground at the sensor
-
Test for short to battery voltage on the signal wire
-
Replace sensor B if circuit checks are normal
Frequently Asked Questions
Is P0848 the counterpart to P0847?
Yes, P0847 is the low circuit code and P0848 is the high circuit code for the same pressure sensor B. They indicate opposite types of electrical faults.
Can a high reading cause transmission damage?
If the TCM believes pressure is higher than it actually is, it may reduce solenoid output, leading to insufficient actual pressure and clutch slippage.
How do I find pressure sensor B on my vehicle?
Consult your vehicle service manual. Sensor B is typically mounted on the transmission case or valve body, often on the opposite side or different location from sensor A.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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