What Does P0877 Mean?
The TCM has detected that the signal voltage from transmission fluid pressure sensor/switch 'D' is below the minimum expected value. This low voltage condition means the TCM cannot accurately determine hydraulic pressure in the 'D' circuit, which is typically used for a specific gear application or torque converter control. The transmission may default to a failsafe strategy.
Common Causes
30%
Shorted signal wire to ground in sensor 'D' circuit
30%
Failed pressure sensor 'D' with internal short
20%
Corroded or contaminated sensor connector
12%
Loss of 5V reference voltage to sensor
8%
TCM internal driver circuit failure
Diagnostic Steps
1
Measure voltage at the pressure sensor 'D' signal wire with key on, engine off — compare to expected idle range.
2
Verify the 5V reference supply is present at the sensor connector; if absent, trace back to the TCM.
3
Disconnect the sensor and measure signal wire voltage — if it rises, the sensor is shorted internally.
4
Check for shorts to ground in the signal wire by testing continuity from the signal pin to chassis ground (should be open).
5
Inspect the transmission case pass-through connector for fluid migration or pin corrosion that could pull the signal low.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The TCM has detected that the signal voltage from transmission fluid pressure sensor/switch 'D' is below the minimum expected value. This low voltage condition means the TCM cannot accurately determine hydraulic pressure in the 'D' circuit, which is typically used for a specific gear application or ...
The most common cause of P0877 (Transmission Fluid Pressure Sensor/Switch "D" Circuit Low) is: Shorted signal wire to ground in sensor 'D' circuit
Typical repair costs for P0877 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The transmission may operate in limp mode with limited gear availability. Driving at reduced speeds is possible but repair should be scheduled promptly to restore full transmission function.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0877 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission Hydraulic Pressure Monitoring
Difficulty
Type
Generic (SAE)
Recommended Tools
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