Transmission Fluid Pressure Sensor/Switch C Circuit Intermittent
What does P0874 mean?
The P0874 code means the vehicle's onboard diagnostic system has detected: Transmission Fluid Pressure Sensor/Switch C Circuit Intermittent. This is a moderate severity code.
Common Symptoms
- Check Engine Light illuminated intermittently
- Occasional harsh or soft shifts
- Sporadic limp mode
- Inconsistent transmission behavior between drives
Probable Causes (Ranked by Likelihood)
- Loose connector at pressure sensor C Very High
- Intermittent wiring fault from vibration or heat High
- Failing pressure sensor C with intermittent output Moderate
- Intermittent internal hydraulic pressure fluctuation Low
Step-by-Step Diagnostic Procedure
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Perform a wiggle test on the sensor C connector while monitoring live data
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Inspect wiring for chafing near hot exhaust components
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Data-log sensor C readings over multiple drive cycles
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Check for manufacturer TSBs on intermittent sensor C issues
Frequently Asked Questions
Why does the code only appear sometimes?
Intermittent faults are often caused by loose connectors, chafed wires, or sensors that fail under certain temperature or vibration conditions.
Can heat from the exhaust cause intermittent sensor faults?
Yes, exhaust heat can degrade wiring insulation over time, causing intermittent shorts or opens that only occur when the vehicle is at operating temperature.
Should I replace the sensor or fix the wiring?
Always check the wiring and connector first. If those are in good condition, the sensor may have an internal intermittent fault and should be replaced.