P0801 OBD-II Trouble Code: Reverse Inhibit Control Circuit Malfunction

check engine light

P0801 trouble code definition

A P0801 trouble code is related to the safety system for manual transmission equipped vehicles to ensure the gear selector is not put into reverse when driving forward. This consists of wiring and a switch located on the shifter mechanism usually where the shifter meshes with the transmission. When turned on, the switch will extend and get in the way of the shifter moving into reverse gear.

What the P0801 code means

P0801 is an OBD-II generic code for a voltage problem with the reverse inhibitor switch. If the switch is functioning correctly, it will send a voltage reading to the powertrain control module (PCM) that is within the manufacturer’s parameters. If not, a Check Engine Light will be illuminated.

What causes the P0801 code?

Likely causes include:

  • Faulty reverse inhibitor switch.
  • Blown fuse.
  • Faulty or damaged wiring for the switch.

What are the symptoms of the P0801 code?

With a P0801, drivers will either be unable to place their vehicles in reverse, or capable of doing so while driving forward. One driver of a SRT10 Viper discovered his super car required more effort to select reverse, but otherwise operated normally.

How does a mechanic diagnose the P0801 code?

The reverse inhibitor switch is a basic on/off type switch, meaning most mechanics will first test to ensure it is not working. Either a professional OBD-II scanner or a power cable can apply voltage to the switch to test it. If it’s not working, your mechanic will replace the switch. If it is working, then faulty wiring will probably be to blame. Your mechanic will inspect all the wiring associated with the reverse inhibitor and repair as necessary.

Common mistakes when diagnosing the P0801 code

While a bad switch is the most likely cause of a P0801, a damaged shifter can be a culprit as well. Replacing a switch on a damaged shifter is only asking for the problem to constantly return.

How serious is the P0801 code?

While you never want to shift into reverse while moving forward, a P0801 still won’t make it easy to do. What is more serious is if the code won’t allow the transmission to be shifted into reverse no matter what.

What repairs can fix the P0801 code?

The most common repairs for a P0801 are as follows:

  • Replacing the reverse inhibitor switch.
  • Repairing any damaged wiring for the switch.
  • Replacing a damaged shifter.

Additional comments for consideration regarding the P0801 code

A P0801 is a fairly rare trouble code but if you do encounter one, you shouldn’t worry. You can continue to drive with the code, just be mindful of how you shift.

Need help with a P0801 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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