AAC showing constant 90%

So I've just replaced the engine harness today with my Wiring Specialties harness. Quite a job but I'll leave that for a write up to follow once I've got it running 100% again.

Anyway after triple checking everything, I started her up. Fired first go no problems, but no cold start idle up, idling around 600-700rpm and slowly dies. Start up again, revs OK to 3000rpm, but again idling very low and slowly dies. Also sounds 'different'. Not quite sure how to describe this.

Anyway plug in ecutalk and check for codes. No codes.

Everything looks normal on the gauges (even compared to logs I took yesterday before I started). Except AAC. It's sitting at a constant 90%. My ecutalk logs from yesterday show the AAC fluctuating around 50% at (cold start fast) idle, increasing to around 75% at 3000rpm. Everything else looks very similar pre and post installing the new harness.

Does anyone know what causes the AAC to report a constant 90%? I'm guessing it has to be something to do with the wiring. Too late tonight now to start pulling it apart again and testing, but hoping someone might have a quick answer for the 90% value.

 

Just check that you have got correct wiring to A/C solenoid, AAC and IACV. Wiring Specialities don't always get the lengths perfect and its easy to mix them up. Check wire colours/coding against your old loom.

Hope this helps

 

Thanks Martin, yeah I checked wire colors and they match.

Will have to pull it off tonight and test.

 

The ECU operates the AAC.
The AAC is a fine air adjustment.
If the ECU is telling the AAC to operate at 90%, it means the ECU wants more air.
A TT at idle should be 15 to 35%.

 

Yes but like I said it was showing a constant 90%. The ecu would not be telling it to maintain a constant 90% from idle to 3000rpm, and from cold to semi warm.

Anyway it's now working. I pulled the plug, completed all the FSM tests for the AAC, all OK. Sprayed a little Inox in the connector, plugged it back in, and now working correctly.

So not sure what the problem was. I?m guessing for some reason it just didn?t get a solid connection. Anyway just glad it?s now working correctly.

For future reference I expect the AAC reporting 90% via the consult port is connection issue, either no voltage getting to the AAC, or a broken connection from the AAC to the ECU. Was one or the other or both.

 

consult AAC is an output, its what the ECU is trying to run the AAC at - so likely it just wasnt able to actuate the AAC/IACV properly.

whats it running at now? 20-30% should be about it on a 'warm' idle.

 

Possibly guys but like I said the problem was a poor connection. All fixed now