Engine system service warning, no codes

[Mr Singh]

its been a while since iv been here as my parents don't have the MK2 Focus saloon anymore, but my mate has a MK3 with an issue that has both of us stumped.

so he has had it a little over a year now and it was originally a write off, cat d i think. the points of impact were right rear corner, left front corner, and some floor damage.

he had issues with a boost control solenoid which he fixed. it was traced back to the ECU connectors that had been damaged (he could pull the pins out of the connector with ease), possibly in the impact. wiring and connectors were replaced and all seemed well, until a few months back. whilst him and his wife were on there way to Nottingham, the car went in to restricted performance, the warning 'engine system service' was on the dash. the ignition was cycled and he carried on. when he got back to Leeds, he asked us to plug my laptop in to see what codes were logged. no codes were logged.

whilst his wife was coming back from her parents in Castleford the same happened, i then plugged my bluetooth dongle in and again no codes. i told him to keep a eye on when it happens and under what conditions.

his wife, and so did he, noticed that the cooling fans sometimes come on at full chat when the engine is switched off after a run or would come on full when the car was started from cold, but its intermittent. i plugged ANOTHER code reader, a snap on reader and again, blank.

he did replace the thermostat as he was saying that it was taking forever to warm up, but that was in December and its still the same with the new one fitted. i did tell him that diesels take a long time to warm up in winter but he didn't listen, anyhow  i cant see how there would be an air lock in the system as it would have worked its way out with the mileage his wife is doing going to and from Castleford every other week it seems.

i think the accident could have had caused form of damage on the ECU, but that would mean getting a replacement ECU and getting it coded to the car. and he doesn't really fancy doing that if its still the same.

[Mr Singh]

anyone???