P073E
Unable to Engage Reverse.
- Generic
- Powertrain
- Generic code
- High severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 7
- AreaTransmission
- 3E
- FaultThe specific fault in that area
What it means
P073E is a generic transmission code meaning the transmission control module has commanded reverse but the transmission has not achieved it. The control unit compared the commanded gear and range selection with feedback from sensors, such as input and output speed, range switch position and clutch or actuator monitoring, and saw a mismatch or no engagement. The exact monitoring strategy varies by transmission type.
Symptoms
- No reverse gear or the car will not move when reverse is selected
- Delayed, harsh or slipping engagement into reverse
- Warning light on the dashboard, possibly with a gearbox or transmission fault message
- Transmission may go into limp mode or restrict gear selection
- Gear indicator flashing or not matching the selector position
- Engine may rev without the car moving backwards
Possible causes
- Low or degraded transmission fluid level or condition causing low hydraulic pressurelikely
- Faulty or misadjusted range sensor, gear selector switch or selector cable/linkagelikely
- Worn or burnt reverse clutch, band or internal seals (automatic) or worn synchro/selector fork (manual or automated manual)possible
- Faulty shift solenoid, valve body fault or actuator for reversepossible
- Wiring or connector damage, corrosion or poor power and earth supply to the transmission control module or solenoidspossible
- Faulty speed sensor giving incorrect feedback during the reverse engagement checkrare
- Transmission control module fault or outdated software where a known issue is documented for the modelrare
How to diagnose
- Read all stored and pending codes and freeze frame data, noting gear commanded, fluid temperature, speed and when the fault set, and check for related transmission or speed sensor codes
- Check for technical service bulletins or known issues for the specific vehicle and transmission type
- Check transmission fluid level and condition where a dipstick or check procedure exists, looking for burnt smell, dark colour or debris, following the manufacturer's procedure
- Inspect the selector cable or linkage for correct adjustment, wear and secure fixings, and confirm the selector position matches the range sensor reading on live data
- Inspect wiring and connectors at the transmission, range sensor and control module for damage, fluid ingress and corrosion, and check battery voltage and earths
- Check live data for commanded versus actual gear, input and output speed and solenoid duty during a reverse selection
- Test solenoid and sensor circuits against specification for the model, as values vary by transmission
- Carry out pressure tests or internal inspection only if the external checks are clear, as procedures depend on the transmission
How to fix
- Correct the fluid level or replace degraded fluid with the specified type, and repair any leaks
- Adjust or replace the selector cable, linkage or range sensor and carry out any required learn procedure
- Repair or replace damaged wiring, connectors or poor earths
- Replace the faulty solenoid, actuator or valve body components as diagnosed
- Repair or overhaul the transmission internals, such as reverse clutch, seals or selector components, if worn or damaged
- Update or reprogram the control module software only where an outdated calibration is a known cause for the vehicle
Can I keep driving?
Avoid driving until it is checked, as having no reverse is a safety and manoeuvring concern and continued use with low pressure or slipping clutches can cause further transmission damage. If the car must be moved, do so only a short distance and with great care.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.