Drive Switch Input Circuit High
What does P0855 mean?
The P0855 code means the vehicle's onboard diagnostic system has detected: Drive Switch Input Circuit High. This is a moderate severity code.
Common Symptoms
- Check Engine Light illuminated
- TCM incorrectly detects Drive when not selected
- Gear indicator may show D at all times
- Transmission shifting behavior may be unpredictable
Probable Causes (Ranked by Likelihood)
- Open circuit in drive switch ground path Very High
- Faulty range sensor stuck reading high in Drive High
- Short to voltage in drive input signal wire Moderate
- Disconnected range sensor connector Moderate
Step-by-Step Diagnostic Procedure
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Verify the range sensor connector is fully seated
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Check for an open ground at the sensor
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Test for short to battery voltage on the drive input wire
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Monitor live data through all gear positions to find the fault
Frequently Asked Questions
Is P0855 the opposite of P0854?
Yes. P0854 means the drive input is stuck low, while P0855 means it is stuck high. They indicate different types of electrical faults in the same circuit.
Can a disconnected connector cause P0855?
Yes, if the range sensor connector comes loose, the signal can float high due to the PCM reference voltage, making the TCM think Drive is always selected.
Is this a safety issue?
It can be. If the TCM thinks the vehicle is in Drive when it is actually in Park, it may cause unexpected behavior during starting or shifting.