P0872 moderate

Transmission Fluid Pressure Sensor/Switch C Circuit Low

The P0872 code means the vehicle's onboard diagnostic system has detected: Transmission Fluid Pressure Sensor/Switch C Circuit Low. This is a moderate severity code.

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Keep driving?: Short distances only
DIY difficulty: hard
Estimated cost: $100 - $500 (parts and labor)

Check Your Fluid First

ANCEL AD310 OBD-II Scanner

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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Read Transmission Codes

LAUNCH CRP123X (Reads All Systems)

Basic scanners only read engine codes. This reads transmission, ABS, and airbag too.

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Common Symptoms

Check Engine Light illuminated
Slipping in specific gear ranges
Soft or delayed shifts
Limp mode in some vehicles

Probable Causes (Ranked by Likelihood)

Short to ground in pressure sensor C signal wire Very High
Faulty pressure sensor C with low output High
Corroded connector at sensor C Moderate
Low transmission fluid level Moderate

Step-by-Step Diagnostic Procedure

Check transmission fluid level
Measure voltage at pressure sensor C connector
Test for short to ground on the signal wire
Replace sensor C if wiring and fluid checks are good

Frequently Asked Questions

Is P0872 the low voltage counterpart of P0873?

Yes, P0872 indicates the sensor C signal is too low while P0873 indicates it is too high. They represent opposite electrical faults.

Can road debris damage the sensor C wiring?

Yes, rocks and road debris can damage the wiring harness on the underside of the vehicle near the transmission, causing shorts to ground.

How do I find sensor C?

Sensor C is typically mounted on the transmission case or valve body. Consult your vehicle service manual for the exact location, as it varies by transmission model.