# Fuel Injector Open Circuit and Gremlins



## aaraya1516 (Nov 7, 2008)

Here's the setup:
I changed the coilpack harness started her up and bam:
17645 - Fuel Injector for Cylinder 1 (N30): Open Circuit
Short to ground on coilpacks also

checked the wires, and noticed two little wires in the ECM plug were making contact. Fixed that and the short to ground coilpack codes vanished, but I'm still stuck with:
17645 - Fuel Injector for Cylinder 1 (N30): Open Circuit

So I changed the fuel injector and nothing changed.

Does anybody have a wiring diagram for an AWP? 
Could the ECM have fried with those two wires making contact? (they were the slender wires, I doubt they were high voltage)
Could it be a relay failing?


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## bigdreamssmallwallet (Jan 22, 2009)

The code says it, OPEN circuit, which means the wire could be broken. Check the continuity between ecu plug and injector plugs. Or just take them out of the tape and check visually.


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## aaraya1516 (Nov 7, 2008)

bigdreamssmallwallet said:


> The code says it, OPEN circuit, which means the wire could be broken. Check the continuity between ecu plug and injector plugs. Or just take them out of the tape and check visually.


Do you know which pin on the ECU plug corresponds to the injectors?


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## AmIdYfReAk (Nov 8, 2006)

Pin 96, Small connector. 

Violet wire in color. 

The 12V supply is over by the waterfall for its power, Check on that as well.


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## 92nick11SLC (Mar 1, 2007)

i had the same issue, i replaced the computer, find someone with a vag-com to xfer over info so ur car doesnt imbolize.


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## AmIdYfReAk (Nov 8, 2006)

AWP = IMMO 3. 
Yours is a AWD/AWW that is IMMO 2. 

You can transfer IMMO 2 with vag-com, Imo3 needs the dealer/to be defeated.


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## Stevebilt (Jul 30, 2010)

Check the pins in the connector, make sure they are seated correctly. The ecu may ne the issue too, you might have smoked.the injector driver with those pins contacting.


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## aaraya1516 (Nov 7, 2008)

UPDATE:

Wires are all good. Continutity checks out fine.

However, there is no power to injector 1 when the key is turned to the "ON" position.


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## aaraya1516 (Nov 7, 2008)

*further diag*

well I checked the injector voltage, and there is about 13v going to the injector while the engine is running.
when the ignition is turned off there is 0v to the injector. I have even tried a new ECM, and it has the same issue.

Any ideas?


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## bigdreamssmallwallet (Jan 22, 2009)

Check the injector grounds to just in case buddy.


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## aaraya1516 (Nov 7, 2008)

bigdreamssmallwallet said:


> Check the injector grounds to just in case buddy.


Since it's only one injector I checked the wired from Injector 1 to the ground wire, and it was fine. If the actual ground for all injectors was bad, wouldn't it say all injectors have an open circuit or short to ground, not just one of them.


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## aaraya1516 (Nov 7, 2008)

AmIdYfReAk said:


> Pin 96, Small connector.
> 
> Violet wire in color.
> 
> The 12V supply is over by the waterfall for its power, Check on that as well.


I verified Pin96 and everything checks out.

where/what is this 12V supply?


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## AutoTech1971 (Mar 31, 2011)

the fuel injectors share a common hot wire.the ecu controls the ground, thus each injector has it's own ground wire. so check ground wire from injector to corresponding pin on ecu connector. have seen it several times, either open or short. if the wire is indeed bad he easiest fix is to overlay a new wire from ecu to injector.


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## AmIdYfReAk (Nov 8, 2006)

AutoTech1971 said:


> the fuel injectors share a common hot wire.the ecu controls the ground, thus each injector has it's own ground wire. so check ground wire from injector to corresponding pin on ecu connector. have seen it several times, either open or short. if the wire is indeed bad he easiest fix is to overlay a new wire from ecu to injector.


100% correct!

The common 12V for them is around the waterfall by the break booster, AFAIK.... 

then again, I don't own/work on Mk4's


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## aaraya1516 (Nov 7, 2008)

AutoTech1971 said:


> the fuel injectors share a common hot wire.the ecu controls the ground, thus each injector has it's own ground wire. so check ground wire from injector to corresponding pin on ecu connector. have seen it several times, either open or short. if the wire is indeed bad he easiest fix is to overlay a new wire from ecu to injector.


Each wire that goes from the Injector to the ECU is fine. I have checked continuity and rechecked that Injector one goes to pin 96 on the ECU. I'm still in search for this 12V power source. I thought the common wire was the ground. I guess I'm backwards on that one. Because of that I didn't verify where those common wires go, but according to wiring diagrams they end up at the fuel pump relay. 

So in summary of what I'm dealing with:
1. steady voltage to the injector while car is running, about 12V
2. no voltage when the ignition turned on but not running
3. no voltage when the ignition turned off
What I have checked:
1. wire from ECU to Injector
2. Wire that connects to common wires for all injectors.
3. Replaced injector with no avail.


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## AmIdYfReAk (Nov 8, 2006)

is it only number 1 that isnt getting power then the ignition is on?


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## aaraya1516 (Nov 7, 2008)

AmIdYfReAk said:


> is it only number 1 that isnt getting power then the ignition is on?


 Correct, all the others get power. I don't remember whether it was 3v or 8v, but they have power with ign on but not running.


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## 92nick11SLC (Mar 1, 2007)

I went thru the same u went through and bought a used ecu from a junkyard and it fixed the problem. Did u try check pin 96 from the plug of the injector to the injector to check resistance of the wire?


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