Transmission Fluid Pressure Sensor Circuit Intermittent
The P0849 code indicates an intermittent fault in the transmission fluid pressure sensor or its circuit. This sensor monitors hydraulic pressure inside the transmission and sends a signal to the PCM. An intermittent signal can cause erratic shifting, slipping, or limp mode. Common causes include a faulty sensor, damaged wiring, poor electrical connections, or low/dirty transmission fluid.
01. Most Common Causes
- Faulty transmission fluid pressure sensor
- Damaged or corroded wiring/connectors
- Low or contaminated transmission fluid
- Intermittent electrical short or open circuit
02. Symptoms You Will Notice
- Check Engine Light on
- Erratic or harsh shifting
- Transmission slipping or delayed engagement
- Transmission stuck in limp mode
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Inspect transmission fluid level and condition; top off or replace if needed.
Step 3: Visually check wiring and connectors for damage, corrosion, or loose connections.
Step 4: Test the pressure sensor signal with a multimeter or scan tool while wiggling harness to reproduce intermittent fault.
Step 5: Replace the sensor if tests indicate intermittent failure.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as intermittent pressure readings can cause transmission damage or sudden failure. Limp mode may limit speed and drivability.
How much does it cost to fix?▼
Diagnosis typically costs $50-$100. Sensor replacement parts range from $30-$80, and labor $50-$150, totaling $80-$230 depending on vehicle.