Transmission Fluid Pressure Sensor Circuit Intermittent
The P0874 code indicates that the Powertrain Control Module (PCM) has detected an intermittent signal from the transmission fluid pressure sensor or switch. This sensor monitors hydraulic pressure within the transmission to ensure proper shift timing and line pressure. An intermittent circuit fault can cause erratic transmission behavior, such as harsh or delayed shifts, and may trigger limp mode to prevent damage.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or delayed gear shifts
- Transmission slipping or stuck in limp mode
- Erratic shift patterns
2. Most Common Causes
- Faulty transmission fluid pressure sensor
- Damaged or corroded wiring/connectors in the sensor circuit
- Low or contaminated transmission fluid
- Intermittent short or open in the sensor circuit
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data to capture conditions when fault occurred.
Step 2: Inspect transmission fluid level and condition; top off or replace if necessary.
Step 3: Visually check the pressure sensor wiring and connector for damage, corrosion, or loose connections.
Step 4: Test the sensor's resistance and voltage output with a multimeter and compare to manufacturer specifications.
Step 5: If wiring and sensor are okay, check for intermittent shorts by wiggling harness while monitoring sensor signal with a scan tool.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances with this code, as intermittent pressure signals can cause transmission damage. If the transmission goes into limp mode, you may lose high gears or reverse. Have it diagnosed promptly.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on whether the sensor needs replacement ($50-$150 for the part) or if wiring repairs are needed. Labor adds $100-$250.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.