A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.
Possible causes
- Dirty oil or wrong viscosity, low oil level
- Faulty or dirty OCV valve
- The VVT-i actuator (the gear on the camshaft) is stuck or worn
- Stretched timing chain
- ECU (rarely)
What you can do yourself
- Check the oil level and when it was last changed. Use the oil viscosity stated in the owner’s manual.
- Check the OCV valve connector (on the cylinder head, by the camshaft) and its wires.
- A scan tool can switch VVT-i on as a check (active test): at idle the engine should run rough or stall. If nothing changes, the OCV valve or the VVT-i actuator is at fault.
Stop and don’t drive on if:
- The Check Engine light is flashing
- The temperature gauge is in the red or the overheating light is on
- The red oil pressure light is on
- Smoke from under the bonnet, a burning or petrol smell
- Strong jerking, knocking from the engine, or the car barely moves
OOleg’s tip: check the connector
Often the cause is simple — there is no contact in the connector (plug). Look at the connector from the back: remove the rubber seal and you will see whether a wire is corroded or has come off completely. Corrosion shows up as green deposits. Ideally, gently pull each wire towards you one at a time: a sound wire stays in place, while a corroded one simply comes off — it needs to be repaired.
Unplug and inspect connectors with the ignition off.
This is the Toyota and Lexus meaning. On other makes this number means something else: if your car isn’t a Toyota or Lexus, change the make at the top.
Source: Toyota Corolla 2003 RM940U; Mitchell 1 tip (import-car.com); obdadvisor.com
The explanation comes from the error code reference in the AvtoElektrik PRO app.