Transmission Fluid Pressure Sensor Circuit Low
The P0847 code indicates that the transmission control module (TCM) has detected a low voltage signal from the transmission fluid pressure sensor or switch circuit. This sensor monitors hydraulic pressure inside the transmission to ensure proper shift timing and line pressure. A low circuit condition can be caused by a faulty sensor, damaged wiring, low transmission fluid, or internal transmission problems. This can lead to harsh shifting, slipping, or limp mode.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or delayed shifting
- Transmission slipping or overheating
- Vehicle enters limp mode
2. Most Common Causes
- Faulty transmission fluid pressure sensor
- Damaged wiring or connector in sensor circuit
- Low or contaminated transmission fluid
- Internal transmission mechanical failure
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and check freeze frame data.
Step 2: Inspect transmission fluid level and condition; top off or replace if necessary.
Step 3: Visually check wiring and connector for damage, corrosion, or loose pins.
Step 4: Test sensor voltage and resistance with a multimeter; compare to manufacturer specs.
Step 5: If sensor and wiring are good, perform a transmission pressure test to rule out internal issues.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as low transmission pressure can cause internal damage. If the vehicle goes into limp mode, drive slowly to a repair shop.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a sensor replacement, but can be higher if wiring repairs or transmission work is needed.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.