Transmission Fluid Pressure Sensor A Circuit Low
The transmission fluid pressure sensor is reading low voltage.
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What it means (plain English)
The computer gets a signal from the transmission pressure sensor that shows the fluid pressure is lower than it should be, typically below 0.1 volts when it should be around 0.5-4.5 volts when the vehicle is running.
What the computer is actually seeing
The PCM monitors the voltage from the transmission fluid pressure sensor, and if it detects a signal below the expected range, it sets the P0845 code.
What a healthy reading looks like
Transmission fluid pressure should be between 0.5 volts and 4.5 volts; if it reads below 0.1 volts, it indicates a problem.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the transmission fluid level; it should be between the 'MIN' and 'MAX' marks on the dipstick.
- 22. Inspect the wiring and connectors going to the transmission fluid pressure sensor for damage, corrosion, or loose connections.
- 33. Use a multimeter to measure the voltage at the transmission fluid pressure sensor. It should be 0.5-4.5 volts. If it's below 0.1 volts, the sensor may be faulty.
- 44. If the sensor voltage is normal, check for a short to ground in the wiring.
- 55. If wiring is good but the issue persists, replace the transmission fluid pressure sensor as it may be defective.
Common causes
- Faulty transmission fluid pressure sensor
- Wiring or connector issues to the sensor
- Low transmission fluid level
- Faulty PCM (Powertrain Control Module)
- Internal transmission failure
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It can be drivable, but you might experience shifting issues or erratic transmission behavior.
Will the code come back after I fix it?
If the issue is resolved, the code should not return. Ensure all connections are secure and the fluid level is correct.
Why does this code sometimes pair with P0746?
P0746 indicates a pressure control issue, which can occur if the fluid pressure sensor is malfunctioning.
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