P0801

Code

LAND ROVER P — Powertrain

Failure in the reverse inhibition control circuit

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 24 EN: 72 RU: 29

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Page language: EN

Causes

Open, short, or high resistance in wiring or connectors for the reverse inhibit circuit
Faulty reverse inhibit solenoid or actuator in the transmission
Faulty transmission range/gear position switch (PRNDL) or related sensors
Poor ground or low battery/ignition voltage
Blown fuse or relay in transmission control power feed
Faulty Transmission Control Module (TCM) or ECU software/firmware issue

Symptoms

Reverse gear will not engage or engagement is delayed
Transmission may refuse reverse but drive gears still work
Vehicle may enter limp/protection mode with reduced shift functionality
Transmission-related warning lamp or MIL illuminated
No change when selecting reverse (no solenoid click)
Reverse lights may be inconsistent if range switch affected

What to check

Read and record freeze frame data and all stored transmission codes using a capable scan tool
Check battery voltage and charging system; ensure >=11 V during cranking and testing
Inspect connectors and wiring for the reverse inhibit solenoid and transmission range switch for damage, corrosion, or loose pins
Listen for solenoid/actuator operation when commanding reverse; check for audible clicks from transmission
Check transmission fuses and relays related to TCM and solenoids
Compare reverse light operation with gear selector to verify range switch function

Signal parameters

Reverse inhibit solenoid command: when TCM commands ON/OFF expect the control line to switch between ~0 V and battery voltage (approx. 11–14 V) or to see a switched ground depending on vehicle harness design
Solenoid coil resistance (typical): roughly 5–50 Ω (refer to vehicle-specific service data)
Solenoid current draw when energized: typically 0.2–2 A (measure with clamp meter)
Transmission range/PRNDL switch: discrete voltage levels or switched 0–5 V outputs for each gear position OR gear position reported over CAN; verify correct reverse position signal to TCM
Supply voltage to circuit: 11–14 V with ignition on/engine running

Diagnostic algorithm

Retrieve all stored codes and freeze frame data; note conditions when P0801 set
Clear codes and attempt to reproduce the fault; record repeatability and conditions (cold start, gear selection, etc.)
Use a scan tool to command the reverse inhibit output while monitoring live data (reverse inhibit state, PRNDL status, TCM outputs)
Backprobe the reverse inhibit solenoid connector: with ignition ON and while commanding, verify supply voltage and command signal change (0 V ↔ battery voltage or switched ground)
Measure solenoid coil resistance with connector disconnected; compare to vehicle spec. Replace solenoid if open/shorted or out of specification
Inspect and wiggle wiring harness between solenoid and TCM while monitoring voltage/continuity for intermittent faults
Verify continuity and resistance between solenoid connector and TCM pin; check for shorts to ground or battery
Check/replace related fuses, relays, and inspect ground points for corrosion/tightness
Verify transmission range switch/PRNDL output: check reverse lamp circuit and/or backprobe PRNDL connector for correct reverse signal while selector is in R; replace or adjust if out of spec
If wiring and components test good, check for TCM faults, poor CAN communication, or software updates; consider TCM replacement or reflash only after confirming wiring and actuators are good
After repairs clear codes and road test to confirm reverse engagement and absence of the fault

Likely causes

Damaged connector or corrosion at reverse inhibit solenoid connector
Short to power or ground in harness between TCM and solenoid
Failed reverse inhibit solenoid coil or stuck valve
Faulty transmission range switch (incorrect reverse detection)
Intermittent ground at TCM or transmission case

Fault status

⚠️ Status

P0801 — Reverse inhibition control circuit fault detected. Reverse function may be inhibited. Inspect wiring, solenoid/actuator, transmission range sensor, fuses/grounds and TCM.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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P0801 — Failure in the reverse inhibition control circuit