What Does P0872 Mean?
The TCM has detected that the signal voltage from transmission fluid pressure sensor/switch 'C' is below the minimum expected threshold. A low circuit reading typically indicates a short to ground, an open in the signal wire, or a sensor that has failed in a way that produces insufficient output voltage. This may cause the transmission to enter a failsafe or limp mode.
Common Causes
30%
Shorted or grounded signal wire in sensor 'C' circuit
30%
Failed transmission fluid pressure sensor 'C' (shorted internally)
20%
Corroded or damaged connector causing high resistance
12%
Open circuit in sensor reference voltage supply
8%
TCM driver circuit failure
Diagnostic Steps
1
Measure the voltage at the pressure sensor 'C' signal wire with the key on — compare to expected range (usually 0.5V–4.5V).
2
Verify 5V reference voltage is present at the sensor connector; if missing, trace the reference circuit back to the TCM.
3
Check for continuity and shorts to ground on the signal wire between the sensor and the TCM.
4
Inspect the sensor connector for fluid contamination, bent pins, or corrosion that could cause a low signal.
5
If wiring is intact, replace the pressure sensor 'C' and verify the signal returns to normal range.
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 'C' is below the minimum expected threshold. A low circuit reading typically indicates a short to ground, an open in the signal wire, or a sensor that has failed in a way that produces insufficient output vol...
The most common cause of P0872 (Transmission Fluid Pressure Sensor/Switch "C" Circuit Low) is: Shorted or grounded signal wire in sensor 'C' circuit
Typical repair costs for P0872 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The transmission may enter limp mode with only one or two available gears. Driving is possible at reduced speed, but have the vehicle repaired soon to avoid being stranded.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0872 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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