Transmission Fluid Pressure Sensor Circuit Intermittent
The P0844 code indicates an intermittent signal from the transmission fluid pressure (TFP) sensor or switch. This sensor monitors hydraulic pressure inside the transmission and sends a voltage signal to the powertrain control module (PCM). An intermittent fault means the signal is erratic or drops out temporarily, often due to wiring issues, loose connections, or a failing sensor. This can cause improper shift patterns, harsh shifting, or limp mode.
01. Most Common Causes
- Faulty transmission fluid pressure sensor
- Damaged or corroded wiring/connectors to the sensor
- Low or contaminated transmission fluid
- Intermittent electrical short or open circuit
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Erratic or harsh shifting
- Transmission stuck in limp mode (e.g., only 2nd gear)
- Delayed engagement when shifting into drive or reverse
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 necessary.
Step 3: Visually check the TFP sensor wiring and connector for damage, corrosion, or loose pins.
Step 4: Use a multimeter to test sensor resistance and voltage signal per manufacturer specs.
Step 5: If wiring and fluid are OK, replace the TFP sensor and clear codes.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The transmission may shift erratically or enter limp mode, which can cause unsafe driving conditions and potential internal damage.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, including parts and labor. The sensor itself is $30-$100, and labor is 1-2 hours.