Tickover problem

Q

I have a problem with a 2005 Renault Grand Scenic 1.6 petrol, which cuts out on starting when cold and won’t tick over until it has heated up, after about 4-5 minutes of revving the engine. The variable cam gear was rattling on start-up, so I replaced it with new, but it is still the same. The only fault code I got when I plugged in a diagnostic reader was ‘DF102’. I have read that it could be a faulty cam sensor, crank sensor, MAP, air temp, air mass or coolant temp, but I’d rather not go down the road of throwing parts at it and spending fortunes.

Do you know of any common faults with cars with these symptoms and any solutions? Scott Hanlon

A

Renault fault code ‘DF102’ refers to ‘Cylinder 4 injector circuit, combustion too strong – permanent fault’. If this is the cause of the failure to tickover when cold, I would expect it to also affect running when the engine is warm.

The most likely cause of the problem is the temperature sender. This can be checked using a diagnostic reader to ensure it is giving the correct temperature readings to the ECU. If the temperature sender is operating correctly, the next step would be to clean the throttle body. These can gum up and can be rectified by a good clean using a carb cleaner aerosol. Finally, I would check the electrical connections to the MAP sensor, as well as the sensor itself, using an electrical switch cleaner to clean both the connecting plug and the sensor. Ensure it is totally dry before refitting and attempting to start up.