Powertrain, generic · Transmission

P0801 Reverse Inhibit Control Circuit/Open

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

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'.

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

Symptoms

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

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–350
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

reverse inhibit solenoidsolenoid wiringengine control module

Related codes

P0803P0812P0813P0806

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.