I.A.C Valve????

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I.A.C Valve????

Postby ecosse » Tue Feb 05, 2013 11:18 pm

Got a jeep 4.0 petrol 2002, with 4 wire iac valve which is not operating, and sets a code p1505 every time after an ignition and start stop cycle, ive included a capture, and i am looking for someone to explain whats happening in the trace, good or bad.

during this capture the idle remains at a very steady 2200 rpm but ocassionally fluctuatting slightly by a couple of hundred rpm

thanks in advance :D
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iac cherokee.jpg
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Re: I.A.C Valve????

Postby Avdr » Wed Feb 06, 2013 8:31 am

Could it be shorted internally?
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Re: I.A.C Valve????

Postby Robski » Wed Feb 06, 2013 11:28 am

Kenny

scope one side at a time, 3 channels, 2X voltage & 1X current & see what it looks like compared to one another ??
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Re: I.A.C Valve????

Postby ecosse » Wed Feb 06, 2013 2:01 pm

will try and do that asap cheers rob

Do i put current clamp round 2 wires at once ? Rob

gona chk and see if ive a wiring diag for it to see whats what and give it a go :D
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Re: I.A.C Valve????

Postby Robski » Wed Feb 06, 2013 2:55 pm

some info on AD Kenny, but i'm not 100% on which model of Jeep you're working on ??

If it's 4X wire i would expect the IAC to be driven in opposite directions (in/out) by 1 pair.
You could also volt drop it from PCM -IAC with a math channel, but maybe something will show up on the current first ??

When you ask about clamping 2X wires with the current probe do you mean 1X from each side of the IAC ? if so i don't see why not as a problem would show up better on 1X screen/capture rather than 2X.
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Re: I.A.C Valve????

Postby ecosse » Wed Feb 06, 2013 3:17 pm

thats exactly what i was thinking rob, clamp both sides 2 wires on one, then the other and with volts too :D

will give it a go and post up after i do an mot :D

its a 4.0 2001 grand cherokee cheers rob :D

still cant see why its got three that apper going in one direction and one in the other, i would have expected 2 and 2 ? :?
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Re: I.A.C Valve????

Postby ecosse » Wed Feb 06, 2013 8:11 pm

sorry no capture guy's, got a little side tracked with another car :x

wont get on it tommorow as i'm off most of the day but maybe late afternoon or friday, thanks

did find this on autodata though? seems a little dif from what ive got dont you think? could well be shorted internally?

also the valve has been replaced by one importes from the states at a cost or 37 quid :o must be well made :D
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jeep not 5v.jpg
jeep data.jpg
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Re: I.A.C Valve????

Postby Robski » Wed Feb 06, 2013 9:54 pm

Kenny

I should imagine the voltage stated is the 'average' voltage as measured with a DMM because it is NBV on the other side & will be until grounded by the PCM, but when i looked at the pin out data on AD the waveform looks different !

Measure the resistance with a DMM on each side & to the body of the IAC. Also if you can find a resistor X2 the same resistance or a consumer X2 on each side of the connector & see if the DTC goes ?
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Re: I.A.C Valve????

Postby ecosse » Wed Feb 06, 2013 11:06 pm

copyright material removed :D
Last edited by ecosse on Sat Feb 09, 2013 7:12 pm, edited 1 time in total.
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Re: I.A.C Valve????

Postby Robski » Wed Feb 06, 2013 11:24 pm

Looks like Derrecks red ch is just a ground.

Can't you ask for a diagram off Mitchell or the likes ?

Without seeing the internals of the IAC I couldn't be 100% now with Derrecks capture ?
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