Engine management light - OH cam fault code

  1. My model of MX-5 is: __MK 2.5
  2. I’m based near: __Thirsk
  3. I’m looking for technical help or recommendations on: __Periodic engine management warning light operation, fault code I forget but it relates to the OH cam position sensor.

I have a 2003 mk 2.5 1.8 that has done approx 99,000 miles. Ever since I’ve owned it approximately 4 years and 30,000 ago, it has an intermittent issue where the engine management warning light comes on a few minutes after starting. It tends to come on within a mile or two of starting off. The fault code relates to the cam position sensor, which has been changed to no effect. It happens roughly intermittently often with a gap of 5-6 weeks between each incidence. The light stays on for a few days then it will just go off again. The engine shows no signs of any issues when the fault light is on, no drop in performance or misfiring. Often a good run will clear the fault - but not always. I’ve had regular oil changes and am using the correct oil for the engine 5W-30. I’ve lived with this for a long time but would like to find the answer if anyone knows what may be causing this. Please let me know if you’ve encountered a similar problem.

Just a thought.
Does the sensor have a permanently attached cable or is there a connector?
My wife had a Peugeot with a sensor problem that didn’t go away when the sensor was replaced.
The problem turned out to be light corrosion on the connector, which was interfering with the transmission of the signal, as the voltages involved are so low.
A bit of cleaning and wiggling completely cured it.

Search P0012, plenty of topics about it.


Thanks for your suggestion, I’ll give it a go.

I’d suspect a Mass Airflow Sensor may be to blame…