Transmission Fluid Pressure Sensor/Switch "A" Circuit
The transmission fluid pressure sensor/switch A circuit is not sending the expected signal to the PCM/TCM. This sensor monitors transmission fluid pressure to ensure proper shift timing and transmission operation. A fault here can cause the transmission to shift incorrectly or use default programming, potentially affecting drivability.
What You Might Notice
- Transmission shifting harshly or at incorrect RPMs
- Check engine light illuminated
- Transmission stuck in limp mode or default gear
- Delayed transmission engagement when shifting
- Reduced fuel economy due to improper shift timing
Most Common Causes
- 1
TFPS sensor failure
The transmission fluid pressure sensor has failed internally and is no longer providing accurate readings to the transmission control module.
- 2
Open circuit in sensor wiring
A broken or disconnected wire in the signal circuit between the sensor and PCM/TCM prevents signal transmission.
- 3
Short to voltage in sensor circuit
The sensor signal wire is shorted to power, sending an incorrect high voltage signal that the PCM/TCM cannot interpret correctly.
- 4
Intermittent mechanical transmission issue
Internal transmission problems affecting fluid pressure can cause erratic sensor readings and circuit faults.
How to Diagnose It
- 1
Check TFPS sensor failure — The transmission fluid pressure sensor has failed internally and is no longer providing accurate readings to the transmission control module.
- 2
Check Open circuit in sensor wiring — A broken or disconnected wire in the signal circuit between the sensor and PCM/TCM prevents signal transmission.
- 3
Check Short to voltage in sensor circuit — The sensor signal wire is shorted to power, sending an incorrect high voltage signal that the PCM/TCM cannot interpret correctly.
- 4
Check Intermittent mechanical transmission issue — Internal transmission problems affecting fluid pressure can cause erratic sensor readings and circuit faults.
How to Fix It
- 1
Replace transmission fluid pressure sensor
Remove the faulty TFPS sensor from the transmission housing and install a new OEM or quality replacement sensor. This is the most common fix for this code.
- 2
Inspect and repair sensor wiring
Check the signal wire harness between the sensor and PCM/TCM for breaks, corrosion, or loose connections. Repair or replace damaged sections of wiring.
- 3
Test PCM/TCM connectors
Verify the PCM/TCM connector pins are clean and making solid contact. Clean corrosion from pins and ensure the connector is fully seated.
- 4
Perform transmission fluid pressure test
If sensor replacement doesn't resolve the code, perform actual pressure testing to rule out internal transmission issues causing low or erratic pressure readings.
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