Ball172

Hi all
Recently while driving the Engine Check light has flashed up and stayed on for a while also the idling is very low (almost stalling) and very lumpy,
so i took it into my local mechanic today to have the codes read. Its throwing up the Throttle Position Sensor, Mass Airflow Sensor and the Idle Control Valve. Now, are these sensors linked?? So if i change 1 it will clear the other faults as i dont see how they can all go at once!?!?
Any help would be appriciated!

Mat

Splitpin

They might not all have gone at once, and might, concievably, all be knackered (although it's probably more likely that one's gone and the ECU is confused). What model year is your car?

Did the garage interrogate the car with a select monitor or just connect the black plugs to read the stored trouble codes out? If they put it on a select monitor, they should have been able to tell straight away whether the TPS was reading correctly by monitoring its output - which would hav e been a good way of confirming whether all the stored codes were "real" errors or not.

Could try resetting the ECU in the first instance to see what symptoms and DTC's recur. Assuming all is not well, and the same errors pop straight back up, replace the MAF sensor, clean out the ISCV, reset the ECU again and see where you get.

Ball172

Thanks for the reply splitpin.
MY car is a uk turbo 1999. The garage connected the black plugs and monitored it that way as my diagnostics port has a dodgy connection wire on the back. The ECU was reset and the same codes came back up. Whats the best way of cleaning these sensors??

Splitpin

You can't clean the MAF sensor. Well, you can spray lotions and potions through them all day but it'll make no difference at all to one that's knackered. Just replace it - part 22794AA010 from your main stealer.

The ISCV is the round thing right on top of the throttle body. Unplug it and undo two screws and it's out. You'll probably find it (and the housing it sits in) are gummed up with black gunk which you can wipe off with some brake cleaner.

The throttle position sensor is just below it. You can't really clean these as they're sealed, but as it's just a variable resistor, you can test it with a multimeter.

Ball172

Thanks for the replys but it turned out to be a sensor in the gearbox! Weird how a sensor down there can make the car idle all over the place and run like crap!