Transmission Fluid Pressure Sensor Circuit High
The P0843 code indicates that the transmission control module (TCM) has detected a voltage signal from the transmission fluid pressure sensor that is higher than the expected range. This sensor monitors hydraulic pressure within the transmission to ensure proper shift timing and line pressure. A high circuit condition typically points to a short to voltage, a faulty sensor, or wiring issues. This can lead to harsh shifts, slipping, or transmission damage if not addressed.
01. Most Common Causes
- Faulty transmission fluid pressure sensor
- Short to voltage in sensor wiring or connector
- Damaged or corroded sensor connector
- Internal transmission problem (e.g., stuck valve)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or erratic shifting
- Transmission slipping or delayed engagement
- Reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Inspect the sensor wiring and connector for damage, corrosion, or shorts to voltage.
Step 3: Test the sensor signal voltage with a multimeter; compare to manufacturer specs.
Step 4: Check transmission fluid level and condition; low or dirty fluid can affect pressure.
Step 5: If wiring and fluid are OK, replace the transmission fluid pressure sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a high circuit condition can cause harsh shifts, transmission slipping, and potential internal damage. Have it diagnosed promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for the sensor and labor, but can be higher if wiring repairs or transmission work is needed.