been in to volvo today..Ouch!!!!

just after some advice, or even a local Volvo independent specialist to help..

My wife's 1.6 99T V40 has had this problem for a while now, where the engine idle seems low, about 600rpm, which makes it a little hard to pull away, this problem gets even worse if you turn the air con on...

it has been in to volvo today, and they say it is showing a network error and think it needs a new CPU unit... at about £700 is this right..?

anyone else had this problem..

any help or advice would be great..

Mark

This is just a total guess, but a "network error" sounds like "we tried connecting our diagnostics tools to your car mate, but we couldn't talk to the CPU therefore new CPU needed".

If so, then it wouldn't be fixing your problem it would just allow them to check for fault codes to find out what to do to fix your problem!

Also (if I'm right about this) it is possibly just dodgy connections into the ECU or the OBD connector.

Re. the idle fault itself, you could try cleaning out the idle air control valve, check the wiring connection to it / clean terminals, possibly replace the valve (expensive though). ECU should open the valve more if there is a drain e.g aircon / PAS, so again could point to a poorly functioning valve.

Pete

cheers for that pete,

but the volvo machine must be talking to the car as it has a airbag fault as well and they told me it was the seat belt per-tensioner on the drivers seat..

but i have cleaned the idle valve, a replacement might be in order..

oh bugger, sounds costly what every i do...

You could try asking to speak to the actual mechanic who diagnosed the "network error": this is rare, but if you can bypass the guys on the front desk then you have more chance of finding out what the fault is.

You could explain to them that you haven't got the £700 for a new ECU at the moment, and you want to understand exactly what the issue is with the ECU so you know if it's replacement can be delayed. You could ask them what else they could try and in what way the ECU is causing the low idle (and if any other failure is possible).

All this is a long shot, of course. But if they believe they are not going to get your business to change the ECU then they might be more willing to come up with some alternatives.

I haven't got a clue what they think this ECU problem actually is. But it isn't something you do first of all. If they think the problem is with the ECU, have they actually done stuff like checked the wiring, connectors, earth connection? Have they tried resetting the ECU by leaving the battery disconnected for ages, or re-programming it?

NOTE: The rest of this post assumes you have the same ECU as my 2000 model year T4 (EMS 2000) and the same idle control motor as me. I don't know if you will or not.

When you cleaned the idle motor did you remove it and clean it? If not try doing that use wynns throttle body spray and make sure the plunger is free to move ok. Careful not to break the paper gasket or get a new one.

Also you can check the communication to the idle valve, but note this procedure will raise a fault code (idle valve failure). Disconnect the wiring from the idle valve and measure with a voltmeter as you turn the ignition on. The voltage should go to 1.2V for about 1 second, and then I think it falls back to 0V until the car is started. In normal operation the voltage is a 160 Hz 0 to 12V pulse which a standard ac voltmeter would probably display as some sort of average voltage dependent on the mark to space ratio (time at 12V vs time at 0V).

Fault code can be cleared only by dealer diagnostics, but engine fault light can be reset by disconnecting the battery for a few hours or maybe only 1/2 hour or so if you connect +ve lead to -ve lead but only do this once you have disconnected both leads from battery and have isolated the battery.

Cheers,
Pete

Originally Posted by peteS40

You could try asking to speak to the actual mechanic who diagnosed the "network error": this is rare, but if you can bypass the guys on the front desk then you have more chance of finding out what the fault is.

You could explain to them that you haven't got the £700 for a new ECU at the moment, and you want to understand exactly what the issue is with the ECU so you know if it's replacement can be delayed. You could ask them what else they could try and in what way the ECU is causing the low idle (and if any other failure is possible).

All this is a long shot, of course. But if they believe they are not going to get your business to change the ECU then they might be more willing to come up with some alternatives.

I haven't got a clue what they think this ECU problem actually is. But it isn't something you do first of all. If they think the problem is with the ECU, have they actually done stuff like checked the wiring, connectors, earth connection? Have they tried resetting the ECU by leaving the battery disconnected for ages, or re-programming it?

NOTE: The rest of this post assumes you have the same ECU as my 2000 model year T4 (EMS 2000) and the same idle control motor as me. I don't know if you will or not.

When you cleaned the idle motor did you remove it and clean it? If not try doing that use wynns throttle body spray and make sure the plunger is free to move ok. Careful not to break the paper gasket or get a new one.

Also you can check the communication to the idle valve, but note this procedure will raise a fault code (idle valve failure). Disconnect the wiring from the idle valve and measure with a voltmeter as you turn the ignition on. The voltage should go to 1.2V for about 1 second, and then I think it falls back to 0V until the car is started. In normal operation the voltage is a 160 Hz 0 to 12V pulse which a standard ac voltmeter would probably display as some sort of average voltage dependent on the mark to space ratio (time at 12V vs time at 0V).

Fault code can be cleared only by dealer diagnostics, but engine fault light can be reset by disconnecting the battery for a few hours or maybe only 1/2 hour or so if you connect +ve lead to -ve lead but only do this once you have disconnected both leads from battery and have isolated the battery.

Cheers,
Pete

Hi Pete,

cheers for that, but i have a funny feeling you may have a different unit to me, as a friend of mine has a Snap on scanner and we did try to read and reset the codes, but the car had a older ecu so it could not be read... but i'm going to get a manual so i can trace the wiring and find the connectors, to give them all a clean with contact cleaner, and you never know...

but thanks for the advice...

Mark