Transmission Fluid Pressure Sensor/Switch Circuit Malfunction
The P0845 code indicates a problem in the electrical circuit of the transmission fluid pressure sensor or switch. This sensor monitors hydraulic pressure inside the transmission and sends a voltage signal to the powertrain control module (PCM). When the PCM detects a voltage reading outside the expected range, it sets this code. Common causes include a faulty sensor, damaged wiring, poor electrical connections, or low transmission fluid. This issue can lead to improper transmission operation, harsh shifting, or limp mode.
01. Most Common Causes
- Faulty transmission fluid pressure sensor
- Damaged or corroded wiring/connectors
- Low or contaminated transmission fluid
- Internal transmission mechanical failure
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or erratic shifting
- Transmission stuck in limp mode
- Decreased fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Inspect transmission fluid level and condition.
Step 3: Visually check wiring and connectors for damage or corrosion.
Step 4: Test sensor resistance and voltage with a multimeter per manufacturer specs.
Step 5: Replace sensor if faulty, clear codes, and test drive.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with P0845 can cause transmission damage or unsafe shifting. Have it diagnosed promptly.
How much does it cost to fix?▼
Typically $50-$150 for parts and labor, but costs vary by vehicle and shop.