P07C8
Intermediate Shaft Speed Sensor B Circuit High.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 7
- AreaTransmission
- C8
- FaultThe specific fault in that area
What it means
P07C8 is a generic code meaning the transmission control module has detected a high voltage signal in the circuit of intermediate shaft speed sensor B. The control unit saw the sensor circuit voltage above the expected range, which can point to a short to voltage, an open circuit or a faulty sensor. The number and location of intermediate shafts depends on the transmission design, so the exact sensor position varies by model.
Symptoms
- Warning light on, such as the engine management or transmission warning light
- Harsh, delayed or erratic gear changes
- Transmission stuck in one gear or in a limp-home mode
- Speedometer or rev reading behaving erratically on some models
- Gear shifts flaring or slipping
- Reduced performance or poor fuel economy
Possible causes
- Faulty intermediate shaft speed sensor Blikely
- Damaged, chafed or corroded wiring to the sensor, including a short to voltage or an open circuitlikely
- Poor connection at the sensor or transmission connector, such as bent pins, corrosion or water ingresslikely
- Metal debris or contamination on the sensor tip or reluctor ring affecting the signalpossible
- Incorrect transmission fluid level or degraded fluid affecting the sensor or internal componentspossible
- Faulty transmission control module or internal fault in the wiring harnessrare
- Outdated control unit software where the manufacturer has issued a known fix for the modelrare
How to diagnose
- Read all stored and pending codes and note the freeze frame data, including vehicle speed and gear selected when the fault set
- Check for related speed sensor codes, as these can help show whether the fault is in the sensor, wiring or control unit
- Check the transmission fluid level and condition using the procedure for that model, as the method varies
- Inspect the sensor, its wiring and the connector for damage, chafing, corrosion, water or loose pins
- Check the live data for intermediate shaft speed and compare it with output and input speed while driving or on a lift as appropriate
- Measure the supply, signal and ground circuits at the sensor connector against the manufacturer's specification, checking for a short to voltage or an open circuit
- Remove the sensor if accessible and check the tip for debris, damage or excessive clearance, using the model specific procedure
- Check for manufacturer software updates or technical bulletins for the vehicle and transmission
How to fix
- Replace the intermediate shaft speed sensor B if it fails testing
- Repair or replace damaged wiring, and clean or replace the connector terminals
- Clean the sensor and mounting area, and correct the cause of any contamination
- Correct the transmission fluid level or service the fluid as the manufacturer specifies
- Update the control unit software only where a known fault is covered by an official update
- Repair or replace the transmission control module only after wiring and sensor faults are ruled out
Can I keep driving?
The car may be driveable, but gear changes can be harsh and the transmission may go into limp mode, so get it checked soon. Avoid heavy loads or towing, and stop if the gearbox slips or shifts become severe.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.