P0814
Transmission Range Display Circuit.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 8
- AreaTransmission
- 14
- FaultThe specific fault in that area
What it means
P0814 is the generic code for a fault in the transmission range display circuit. This is the signal that tells the instrument cluster or gear indicator which position the selector is in (P, R, N, D and so on). The control unit has seen a circuit problem or a communication mismatch between the range information it holds and what the display circuit is reporting.
Symptoms
- Gear selector position indicator on the dash is blank, flickering or showing the wrong gear
- Transmission warning light or malfunction indicator lamp on
- Starting problems or no-start in some positions, if the range signal is also used for start inhibit
- Reversing lamps not working or working at the wrong time on some models
- Harsh, delayed or erratic shifts in some cases
- Transmission may default to a limited or fixed gear (limp mode) on some models
Possible causes
- Faulty or misadjusted transmission range sensor or selector position switchlikely
- Damaged, chafed or corroded wiring, or poor connector contact in the range display circuitlikely
- Selector cable or linkage out of adjustment, so the physical position does not match the sensor signalpossible
- Water ingress or contamination at the sensor or its connectorpossible
- Fault in the instrument cluster or the data link between the cluster and the transmission control unit, depending on the vehicle's network layoutpossible
- Faulty transmission control unit or an outdated calibration, where the manufacturer has identified it as a known causerare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting any other transmission, network or cluster codes
- Compare the selector position with the gear shown on the dash and the range reported in live data as you move through each position
- Visually inspect the range sensor, selector linkage and wiring for damage, corrosion, leaks and loose connectors
- Check the selector cable or linkage adjustment against the manufacturer's specification for the model
- Check the battery voltage and the supply, earth and signal circuits at the range sensor with a multimeter, using the wiring diagram for the vehicle
- Test the wiring for continuity, short circuits to earth or voltage, and high resistance
- Check for network communication faults between the transmission control unit and the instrument cluster
- Check for relevant technical service bulletins or calibration updates for the specific model and gearbox
How to fix
- Repair or replace damaged wiring and clean or replace corroded connectors
- Adjust the selector cable or linkage and set the range sensor to the specified position
- Replace the transmission range sensor or selector switch if it fails testing
- Dry out and seal the connector area and fix the source of any water ingress
- Repair the network fault or replace the instrument cluster if it is proven faulty
- Update or replace the transmission control unit software only where an outdated calibration or faulty unit is confirmed
Can I keep driving?
Medium severity
The car can usually be driven short distances, but get it checked soon. If the selector position is not reliably detected, the car may not start, may select gears incorrectly or may go into limp mode, so avoid long journeys until it is fixed.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.