P0801Generic code

P0801 Code: Reverse Inhibit Control Circuit

The P0801 code means there is an electrical fault in the control circuit of the reverse inhibit solenoid. It can keep reverse from engaging, or let it engage at speed. Check the fuse, relay, connector and wiring before you replace the solenoid.

Severity
Medium
Can I keep driving?
Yes, but with caution
Estimated cost
$40 to $400
Difficulty
Medium
System
Transmission
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0801 code means

On some manual transmissions, for example six-speed units in GM and Ford vehicles, a solenoid keeps you from engaging reverse above a certain speed so the gears are not damaged.

The computer watches the control circuit from its own driver transistor. The P0801 code points to an electrical fault in that control circuit. Before you replace the component, check the fuse, relay, connector and wiring, because they are the most common cause.

If the solenoid does not work, it may be impossible to engage reverse, or it may fail to block reverse at speed. Check the shifter mechanism as well.

Always start with the simplest items: fuse, relay and connector. Then check power, ground and signal with the component connected (using back-probes), and finally the continuity of each wire up to the computer. Only if all of that is good should you replace the component.

P0801 code symptoms

  • Check engine light or another warning light on.
  • Reverse will not engage, or it can engage at speed.

Likely causes of the P0801 code

  1. Damaged connector, loose, broken or corroded.
  2. Blown or faulty fuse or relay.
  3. Wiring cut or shorted between the component and the computer.
  4. Failed component: the coil, the motor or its internal electronics.

How to diagnose the P0801 code step by step

  1. Command the component with the scan tool and see whether it responds.
  2. Check the fuse and relay. Measure voltage on both sides of the fuse, and swap the relay with an identical one.
  3. Measure the supply at the connector. Battery voltage with the key on or when it is commanded.
  4. Measure the component resistance and compare it with the manual, and check the insulation to ground too.
  5. Check the control wire for continuity up to the computer and for shorts.

How to fix the P0801 code

  • Repair the connector, the wiring or the power supply.
  • Replace the reverse inhibit solenoid if it does not respond with correct power and command.
  • Clear the codes and verify the repair.

Technical reference data

  • 12 V solenoid.
  • These are approximate values: check the manufacturer data for your vehicle.

Brand-specific notes

This code is common on performance cars with a six-speed manual transmission. The models below are the ones the source mentions.

P0801 on Chevrolet

Common on the Chevrolet Camaro and Corvette with the Tremec transmission.

P0801 on Ford

Common on the Ford Mustang.

Frequently asked questions about P0801

What does the P0801 code mean?
It is a generic OBD2 code that means there is an electrical fault in the control circuit of the reverse inhibit solenoid. That solenoid keeps reverse from engaging above a certain speed.
Can I drive with a P0801 code?
Yes, with caution. Reverse may not engage at all, or it may engage at speed, so be careful when you shift.
What does the reverse inhibit solenoid do?
On some manual transmissions, for example six-speed units in GM and Ford vehicles, a solenoid keeps you from engaging reverse above a certain speed to prevent damage.
Does the part always have to be replaced?
No. Check the fuses, relays, connectors and wiring first.
How much does it cost to fix P0801?
As a rough guide, between $40 and $400.
Will a P0801 code clear itself?
It can go out if the fault was a momentary bad connection, but a blown fuse or a failed solenoid will bring the P0801 code back.
What is the most common cause of P0801?
A damaged connector, a blown fuse or relay, or cut wiring. These are far more common than a failed solenoid.

Related codes

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