after fitting my gearbox last week thought id just check for any fault codes, showing 33 and 24. 33 is for my missing speed sensor which i have coming. 24 is for air control valve/ circuit. could this be a red herring cos of the limited power due to code 33, or could it be leaving a vacuum hose or something off im pretty sure i haven't. just checked for boost leaks cant see any.

car is a 99 uk turbo

does anyone have any ideas maybe iv missed something but i do 60 miles a day and dont want to bugger anything up!!!

 

Is it possible that at some point in the past, you or someone else might have started the engine with the ISCV connector off? If so, this would cause what you're seeing (A Select Monitor would know whether this was a current or historic error). Obviously if you disconnected the battery and are sure the engine hasn't since been started with the valve unplugged then this is ruled out but it's something to think about.

24 shouldn't be triggered as a "side effect" of 33, but you can make sure quite easily:

Reset your ECU by disconnecting the battery, start the car and leave it idle for a couple of minutes (do not move it), and then check via the black plugs whether there are any stored errors. If 24 has come back, you know that the ISCV really is dodgy. If you get no errors at all, drive the car round the block and check again. If you have 33 and 24 again, chances are the missing speed sensor is the cause for both.

Bottom line is that if the ISCV is on its way out, your car will still be drivable, you'll just notice the idle becoming more and more irregular so it's one of those things where you'll know when you've got to do something.

 

ok thanks ill disconnect the battery now to reset, code 24 was not there about a month or so ago because i checked for codes when i had a hesitation. ISCV was not disconnected when the gearbox came out. im not aware that the ISCV has been disconnected in the last 4 years since iv owned the car. Thanks splitpin your input is always useful!!! lets see what happens.........