No announcement yet.

Thanks for OPCOM suggestion:- P0505 iac voltage HIGH

  • Filter
  • Time
  • Show
Clear All
new posts

  • [Corsa B 1993-2000] Thanks for OPCOM suggestion:- P0505 iac voltage HIGH

    Hi, been trawling the net and this forum came up as the best one to trust and it has proven to be true. OPCOM was the recommendation, and OPCOM was the ONLY thing that worked...

    So a little background may help someone else. If you have a Corsa B with the 10XE lump, and your management light is on/sometimes on BUY AN OPCOM! It REALLY does work,( and 327ELM, paperclips, switching the ignition on while full throttle and foot brake is on etc DOESN'T). My sons car a 1998 Corsa 1.0GLS ran fine for a while but after a prolonged period of idleness, I've started using it for a runabout. He's got something else now, so I'm not depriving him.
    Cutting to the chase, it started doing weird stuff. Idled a bit crap but steady throttle was awful, revs up and down "rhythmically" by about 200 rpm off idle. Engine management light had started by coming on on the overrun after 10 minutes or so, was now on permanently.
    Hooking the OPCOM shows 3 stored codes, the idle motor voltage low was stored and inactive, as was the usual EGR one. The motor voltage was expectd as I'd disconnected it a couple of times when testing but the only active one was "0505 idle air control voltage high". Clearing it and re-reading sorts the problem for a second or so, thus that's the fault
    However, a very brief look up suggests that's an ECU issue, which I could do without (especially as I've just got a throttle body and switches to swap over just in case )

    I'll pull the ECU and see if there's any spurious connector issue that may be causing it, and may even swap the body anyway JUST for the practice but if anyone on here has any better suggestions I'd be grateful. An ECU probably won't be that disastrous to source but be even more satisfying to fix the begger!

    Incidentally, anyone round my neck of the woods(Luton, Beds/bucks/Herts/ Cambs) needs the OPCOM plugged in to their motor, just drop me a PM and we'll see if we can work something out.
    Last edited by mytocon; 05-04-2014, 01:29 PM. Reason: forgot location :-(

  • #2
    Can't help you much but top first post, welcome!
    Vauxhall Vectra 1.9 CDTi SRi - New Car
    Black 1.2 Corsa SXI Project - Sold
    Aruba Blue 1.0 Corsa Project - Sold


    • #3
      The code plus symptoms on overrun and idle confirm the diagnosis. However, before concluding it's the ECU check the idle valve itself, the connectors and the wiring. Better the problem is there than in the ECU. I'd try clearing the codes, disconnect the idle valve and run the engine. You'll get fault codes but ignore them. Just check whether it is seeing the same P0505 code. If it seeing it with the idle valve disconnected then you know it's not the valve itself. If it doesn't come up with P0505 with the idle valve disconnected then you know it is the valve that's the source of the problem.

      If it's not the valve then check the connectors and wiring for continuity and shorts.
      1972 Viva restoration thread -