16497 - PLEASE help !

[mikes3]

Hey fellas - Posted this over in the VAGCOM forum, so thought Id put it here too. Ive posted in a couple of other threads too, so I apologise if I'm going over old ground. This is more of a concise and to the point post about my current problems, please bear with me.


2003 S3 - BAM engine

16497 - Intake Air Temp G42 - signal too high

Ok, so this has been running a couple of weeks now. The ECU threw the code up and as a result, the car has lost power, intermittent boost problems and runs lumpy on idle.

I have sourced a brand new sensor from Audi, and replaced. Cleared the code, turned the ignition and the fault came straight back. I believe this fault has to show on 3 separate startups to show an Engine light on the dash (which it does).

Anyway, I scoured the net and found a couple of walkthroughs/guides as to the symptoms, causes and possible cures of the said fault. Both of them suggested that there should be 5 volts DC across the 2 connector plug terminals with the ignition on. I tested, and found nothing, zero volts. I gather that if the ECU sees the high or low voltage limit it will throw the fault. So, convinced I had a wiring fault somewhere, I set about finding it.

Stripped back the loom running under the battery tray and air box, traced the cable back as far as the loop near the pollen filter. I wanted to chase it back to the ECU, but the passenger wiper blade is jammed on the spline and Im having trouble removing it. I cut the cable at the loop, and tested voltage from te ECU - still nothing. (the cable back to the sensor is clear, and has good continuity).

I'm at the stage now where Im banging my head against the wall. Am I actually chasing a lost cause towards the ECU, or is some other sensor/signal somewhere causing the fault (ie MAF or MAP). I have removed the MAF and cleaned as per the guides on here, being very careful with it. No other faults showing on the diagnostic at all, only 16497.

To add to it all, I registered on ERWIN for an hour an pulled up the wiring diagrams, only to find the actual pictures weren't showing (using IE8). Does anyone know if the sensor cable routes directly to the ECU, or does it go via any connectors ? Maybe one has unseated or has a bad pin. I don't know.

I've chucked a lot of time and money at it so far, and I haven't got a pot left to pee in. Can't afford to be throwing new sensors at it without valid reason.

Any help from you guys is greatly appreciated. You will make a jaded (and very tired) Audi lover very happy.

Best Regards.​

 

[<tuffty/>]

I had a similar issue with a knock sensor... I got the following fault randomly...

16712 - Knock Sensor 1 (G61): Signal too High
P0328 - 35-10 - - - Intermittent

I rewired the knock sensor back to the ECU and bingo... all better

Whether this will work for you I don't know but its worth a punt...

<tuffty/>

 

[mikes3]

Thanks again tuffty. As soon as I can get the wiper blade off, I'll check the cable right back to the ECU and hopefully will see 5 volts and the replace the cable (problem solved !?)
Find it a little hard to fathom how a wire can just break up there by the ECU though, its not seeing any action at all up there, no moisture or movement. This is leading me to think its something else ... but what ?

 

[Matt82]

have you checked for voltage where the cable joins the connector, could be as simple as that

 

[NHN]

AS posted on the other thread.

The G42 has as you say 2 legs, 1 goes to earth & is shared connection with other I suspect senders as it shows it as 220 Sender Earth, other leg goes to the J220 Motronic Control Unit pin 85, I would goto that pin connection disconnect the existing pin then add a new wire & test for any voltage from that new wire mate.

Also get a meter & test between the sender wire pin 1 & the pin 85 wire & see if there is continuity on that wire as it shows as straight threw between the 2 points.

Hope that helps.

 

[mikes3]

Thanks NHN.

I saw the descriptions on the ERWIN pages, just not the diagrams themselves so have no idea of the current path. Do you happen to know what or where the J220 MCU is ? Is that just the Audi name for the ECU itself ? As a long shot, do you have a copy of the diagram I could have a look at ? I'm determined to get this wiper blade off today, was told there is a special puller you can buy to get them off with.

Just as info for anyone else who happens to mess with this sensor, the earthed wire is the YELLOW wire, and the signal is the GREEN one. Thanks for the suggestions - keep them coming. I will post some photos of what I've been doing as soon as I get further.