P0801: Reverse Inhibit Control Circuit/Open

On GM manual gearboxes (Tremec T56/TR6060 in Corvette, Camaro, CTS-V and ATS-V) the engine module drives a solenoid that blocks reverse while the car moves forward. P0801 means its control circuit is open. GM's tables describe the check: the low-side driver's internal diagnosis flags an open line with at least 9 V and the engine above 250 rpm, 20 failures in 25 samples of 250 ms – about 6 s; in 2006 a 5 s comparison of commanded and actual driver state. GM rates it type C, emissions-neutral and without MIL, from 2019 with a 'service vehicle soon' note. Depending on how it fails, reverse cannot be engaged or is no longer blocked. The title was updated to the current J2012 wording with '/Open'.

Symptoms

• Reverse hard or impossible to engage
• Reverse no longer blocked
• Service note in the driver display, usually no MIL

Most likely causes

• Connector at the reverse inhibit solenoid loose or corroded
• Solenoid coil open
• Harness between engine module and gearbox damaged
• Engine module driver faulty

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the fluid level and condition
2. Check the continuity of the wire between the component and the control module.
3. Read the input and output speed in live data
4. Check the connector and wiring
5. Check for other related engine codes
6. Consult the manufacturer's procedure for the transmission

Good to know

• Repair difficulty: medium

What each character of P0801 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 8: Transmission
• 01: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0801?

Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.

What causes code P0801?

The most common causes are: connector at the reverse inhibit solenoid loose or corroded; solenoid coil open; harness between engine module and gearbox damaged.

Related codes

• P0803Upshift/Skip Shift Solenoid Control Circuit
• P0812Reverse Input Circuit
• P0813Reverse Output Circuit
• P0806Clutch Position Sensor A Circuit Range/Performance

Sources

• gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
• gsi.ext.gm.com: 19OBDG03A Diagnostics
• gsi.ext.gm.com: 19OBDG03B Diagnostics
• gsi.ext.gm.com: 2006file1

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.