P07F1

What it means

P07F1 is a generic powertrain code for a fault in the Input/Turbine Shaft Speed Sensor 'C' circuit. The transmission control unit monitors the signal from this sensor and compares it with other speed inputs such as engine speed and output speed. It set the code because the signal was missing, erratic, out of range or implausible. Which sensor is labelled 'C' and how the fault is judged depend on the vehicle and transmission, so check the manufacturer's data for the exact model.

Symptoms

• Gearbox warning light or malfunction indicator lamp on
• Gearbox goes into limp mode, often stuck in one gear
• Harsh, delayed or flared gear changes
• Erratic or non-working speedometer or rev reading on some models
• Torque converter lock-up not engaging, causing higher fuel consumption
• Transmission refuses to shift manually or by paddle

Possible causes

• Damaged, chafed or corroded wiring or connector to the input/turbine speed sensor Clikely
• Faulty input/turbine shaft speed sensor Clikely
• Metal debris or contamination on the sensor tip or in the fluid affecting the signalpossible
• Low, degraded or incorrect transmission fluidpossible
• Damaged or worn sensor reluctor ring or target wheelrare
• Internal transmission fault or fault in the transmission control unitrare
• Outdated control unit software where the manufacturer has issued a correction for this faultrare

How to diagnose

1. Read all stored and pending codes and note any related speed sensor, solenoid or communication codes.
2. Review freeze frame data to see engine speed, vehicle speed, gear and temperature when the fault set.
3. Check the transmission fluid level, condition and smell, following the manufacturer's procedure for the model.
4. Inspect the sensor wiring and connector for chafing, heat damage, water ingress, corrosion and bent or loose pins.
5. Check live data for input speed, output speed and engine speed while driving or on a lift, and look for dropouts or implausible values.
6. Test the sensor circuit for supply, earth, signal continuity and shorts, and check the sensor resistance or signal against specification.
7. Remove the sensor if accessible and check the tip for debris, damage or a wrong air gap, and inspect the reluctor if visible.
8. Check for manufacturer service bulletins or software updates relevant to the vehicle.

How to fix

• Repair or replace damaged wiring and clean or replace corroded connectors.
• Replace the input/turbine speed sensor C if it fails testing.
• Clean or replace a contaminated sensor, and service the transmission fluid and filter if debris is found, as the manufacturer specifies.
• Correct the fluid level or replace degraded fluid with the correct specification.
• Repair or replace a damaged reluctor ring or internal component after inspection.
• Update the control unit software only if the manufacturer lists it as a fix for this fault, or replace the unit if proven faulty.

Can I keep driving?

Nearby codes

• P07F0GenericTransmission Range Multi-Function Select Circuit High
• P07F2GenericTransmission Range Control Module Communication Circuit