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OBD-II Code

P0801

Severity

Not yet reviewed

Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.

Can you drive it

We cannot say

Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.

Indicative cost (USD)

$150–$900

From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.

P0801 is the electrical-circuit fault for the Reverse Inhibit Control Circuit — the TCM (or BCM on some applications) commands a solenoid or relay to physically block reverse engagement above a programmed road speed (typically 5-7 mph), and the driver circuit reads open, shorted, or out-of-spec.

How a shop works this

Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.

  1. Note every code that is set, not just this one.

    Codes that appear together usually narrow the cause faster than any one of them read alone.

  2. Read the freeze frame — the conditions the fault was recorded under.

    Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.

  3. Confirm the fault is current rather than history.

    Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.

  4. Then follow the diagnostic notes further down this page, in the order they are written.

    They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.

If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.

Common symptoms

  • Check engine light
Read the full diagnostic procedureP0801 is the electrical-circuit fault for the Reverse Inhibit Control Circuit — the TCM (or BCM on some applications) commands a solenoid or relay to…

P0801 is the electrical-circuit fault for the Reverse Inhibit Control Circuit — the TCM (or BCM on some applications) commands a solenoid or relay to physically block reverse engagement above a programmed road speed (typically 5-7 mph), and the driver circuit reads open, shorted, or out-of-spec.

Cheapest-first

  1. scan for companion codes (a lone P0801 with no P0700/P0715 is almost always external wiring), then unplug the reverse inhibit solenoid connector at the transmission and ohm the solenoid pin-to-pin.
  2. Typical PCS-B/inhibit-style solenoid spec lands 8-30 ohms cold; on/off inhibit solenoids on Subaru 4EAT/Toyota A340 spec 11-15 ohms, and infinite (open) or under 3 ohms (shorted) condemns the solenoid outright.
  3. Then ohm pin-to-ground on each leg — anything under 100k ohms to case ground on what should be a floating circuit means insulation breakdown from ATF migration up the harness.
  4. Back-probe the driver circuit with a low-amp clamp and watch for the commanded 0.5-1.5 A pulse on key-on; absent current means TCM driver fault or open wire upstream.
  5. Expensive-misdiagnosis caveat: on Chrysler 545RFE/68RFE the reverse inhibit logic lives inside the integrated solenoid pack assembly (TRS + pack on the valve body), so a clean P0801 with no movement issues frequently presents as a single-circuit code when the actual problem is the entire solenoid pack going progressively out of tolerance — replacing one wire or chasing one pin is wasted labor when the whole pack is shedding debris.
Vehicle-specific patterns1998-2005 Subaru Forester/Outback/Legacy with the 4EAT throws P0801 from the dropping resistor or the reverse inhibit solenoid in the valve body itse…
  • 1998-2005Subaru Forester/Outback/Legacy with the 4EAT throws P0801 from the dropping resistor or the reverse inhibit solenoid in the valve body itself — the solenoid is accessible after pan drop, $80-150 part, plus filter and fluid.
  • 1995-2004Toyota 4Runner/Tacoma and early Lexus GS300/LS400 with the A340/A340E (and A343F variant) sets the equivalent OE code from the inhibitor switch on the trans range sensor going out of adjustment or developing internal corrosion — RepairPal and AAMCO both flag this as the #1 cause on those platforms, $120-250 for the switch.
  • 2003-2010Dodge Ram 1500/2500 with the 545RFE and later 68RFE set P0801 frequently from solenoid pack degradation at 70,000-150,000 miles — the SAE J2012 code points at one circuit but the pack as a whole is the failure, and Chrysler dealers commonly replace the full solenoid pack assembly ($500-900 parts + labor at independents per AAMCO survey data).
  • 2007-2014Nissan Frontier/Xterra with the RE5R05A throws it from internal harness chafe at the case connector pass-through.

Estimated repair$150 to $900.

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