P07FB
Stuck in Gear 10.
- Generic
- Powertrain
- Generic code
- High severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 7
- AreaTransmission
- FB
- FaultThe specific fault in that area
What it means
P07FB means the transmission control unit has decided the gearbox is stuck in 10th gear (generic SAE J2012 definition). It sets when the gear ratio calculated from input and output shaft speeds matches 10th while a different gear is commanded, or the box will not shift out of 10th. It only applies to vehicles with a ten-speed automatic or similar transmission.
Symptoms
- Gearbox stays in 10th gear at low speed
- Sluggish or very weak pull-away and acceleration
- Engine labouring, juddering or stalling when slowing down or stopping
- Gearbox warning light or malfunction message, often with limp mode
- Harsh or no shifts, or a flare in engine revs between gears
- Poor fuel economy or high revs on the motorway
Possible causes
- Shift solenoid or valve body fault (sticking, failed electrically or blocked by debris)likely
- Low, degraded or contaminated transmission fluid, or the wrong fluid specificationlikely
- Wiring or connector fault between the transmission control unit and solenoids or speed sensorspossible
- Input or output shaft speed sensor fault giving a wrong ratio readingpossible
- Internal clutch or brake pack wear or failure so the correct gear cannot be engagedpossible
- Transmission control unit software fault or outdated calibration (model dependent, check manufacturer service information)rare
- Mechanical damage inside the gear set or shift mechanismrare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting gear commanded, vehicle speed, engine speed and fluid temperature when the fault set
- Check for related codes such as speed sensor, solenoid, or ratio codes, and diagnose those first
- Check transmission fluid level, condition and smell, following the procedure for your model, as some units are sealed and need a specific method
- Inspect wiring, connectors and the transmission harness for damage, corrosion, chafing or fluid ingress
- With a scan tool, compare live input speed, output speed and commanded versus actual gear on a road test
- Test shift solenoid circuits and speed sensors against the manufacturer's specifications for resistance and signal
- Check for available software updates or technical bulletins for the transmission control unit on your model
- If electrical checks pass, carry out a pressure test or inspect the valve body and internals as the manufacturer's procedure directs
How to fix
- Repair or replace damaged wiring or connectors in the transmission harness
- Replace faulty speed sensors or shift solenoids confirmed by testing
- Correct fluid level or renew fluid with the correct specification, and replace the filter where the design allows
- Clean or replace the valve body or sticking valves if debris or wear is found
- Apply a manufacturer-released software update if an outdated calibration is a known cause for that model
- Repair or rebuild the transmission internals if clutch, brake or gear set damage is confirmed
Can I keep driving?
High severity
Limit driving and avoid it where possible, as being stuck in 10th can cause clutch slip, overheating and stalling when slowing or pulling away. If the car must be moved, keep the trip short and gentle and have it checked promptly.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.