P0574
Cruise Control System - Vehicle Speed Too High.
- Generic
- Powertrain
- Generic code
- Low severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 5
- AreaVehicle speed, idle control and auxiliary inputs
- 74
- FaultThe specific fault in that area
What it means
P0574 is the generic code for the cruise control system seeing a vehicle speed that is too high. The control unit sets it when the road speed signal is above the limit allowed for cruise control operation, or the speed is higher than the set speed by more than the permitted margin. The exact threshold and the module that sets the code vary by manufacturer and model.
Symptoms
- Cruise control will not engage or cancels itself
- Cruise control disengages on downhill stretches or when speed rises above the set speed
- Cruise control indicator light flashing or the system showing as unavailable
- Malfunction indicator lamp on in some vehicles
- Speedometer reading erratic or inconsistent with actual speed in some cases
Possible causes
- Driver using cruise control above its permitted speed range, or speed overrunning the set speed on a long descentlikely
- Faulty or erratic vehicle speed signal from a wheel speed sensor or output speed sensorpossible
- Damaged wiring, poor connections or corrosion in the speed sensor circuitpossible
- Tyre size or final drive change causing the speed signal to read higher than actual speedpossible
- Fault in the cruise control switch, brake switch or clutch switch circuit causing incorrect cruise control operationpossible
- Fault within the engine control unit, ABS module or instrument cluster, or outdated softwarerare
How to diagnose
- Read all stored and pending codes and freeze frame data to see the speed, load and conditions when the code was set
- Ask the driver how the cruise control was being used, such as speed set and whether on a descent
- Check for other speed sensor, ABS or transmission codes that point to a common cause
- Inspect the wheel speed sensor and output speed sensor wiring and connectors for damage, corrosion or contamination
- Compare live vehicle speed data from the engine control unit and ABS module against a known true speed, such as GPS speed
- Check tyre sizes and condition, and confirm that nothing has been changed that alters the speed signal
- Test the cruise control switch, brake switch and clutch switch operation and their signals against the manufacturer procedure
- Check for any applicable software updates for the affected control units, following the manufacturer procedure
How to fix
- Advise correct cruise control use if no fault is found, and clear the code after confirming normal operation
- Repair or replace damaged wiring and connectors in the speed sensor circuit
- Replace a faulty wheel speed sensor or output speed sensor
- Fit the correct size tyres or correct the speed signal calibration to match the vehicle specification
- Replace a faulty cruise control, brake or clutch switch
- Update or repair the affected control unit only if a known fault or outdated calibration is confirmed
Can I keep driving?
Low severity
The car can normally be driven as the main effect is loss of cruise control. Book it in soon, especially if the speedometer or ABS also behave oddly, as an inaccurate speed signal can affect other systems.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.