Help with Codes 17580/P1172, 17579/P1171

[willdudeuk]

Thanks Crasher, so you would recommend stripping the engine harness back to the wires for inspection, concentrating on the areas of the loom that pass through the bulkhead and where it was sitting in all the crap and mud under the scuttle area.

Fingers crossed this will identify a broken / chaffed / damaged wire and be the root cause of all my throttle body issues.

Shall report back when I get time to strip everything out and inspect the loom thoroughly.

[Crasher]

On the one I have been doing (our loan car A4) I had to gut the interior, unwrap the harness and follow the wire in question pulling at it until it broke, the damage was invisible until I pulled at it.

[willdudeuk]

Ahhh ok so you are suggesting the damage / break may not even by visible.....

Think I will just replace all 6 wires from the ecu to the throttle body as you suggested to avoid any of this "trying to locate the broken wire"!

Just trying to understand what crimps / terminals I need at the ECU end.....

From the wiring diagram you have sent me I have 2 x 1.0mm wires and the rest are 4 x 0.35mm and comparing this to the pin locations on the ECU I can see what male pins go into the ECU connector.

The 2 x 1.0mm have a spade connection (need female equivalent of this) and the 4 x 0.35mm have a pin (need female equivalent of this).

I should of measured these with calipers but didn't.

Can send you a picture if it makes it easier to identify.

[Crasher]

You can buy a new T60 plug which comes with the terminals under part number 5Q0 906 379 and this is about £12 from a VAG dealer so you get the pins that way but they are evil little buggers to do correctly or you can use the VAG repair wires listed for this plug such as 000 979 026 EA for the 0.5mm2 CSA wires with a 2.8mm terminal in Gold plate for about £13 for a double ended wire but these are not long enough for the job. A new engine harness is £300. Watch the video below.

[willdudeuk]

Thanks yet again for this very useful information Crasher....

Have you got part numbers for the terminals for the 0.35mm² and 1.0mm² CSA wires?.....if not I can just purchase the T60 plug....

When you say they are "evil little buggers" to do correctly, can you elaborate a bit further about what you mean by this?

Can't be any harder than crimping the repair wires I've made already?

[Crasher]

If they are the ones I expect then they are not crimped, you just push the wire into the pin almost Scotch Lock style, the VAG repair wires are crimped.

[willdudeuk]

Well I had a go at depinning the ecu as per the wiring diagram supplied but it’s a nightmare to do. Think I may have damaged a release pin as I can’t remove one of the larger 1.0mm CSA wires. Don’t won’t force it out and wire break with terminal stuck inside. May just have to settle for a complete harness from the dealership. The harness is tightly bunched and I don’t want to further stress it especially in colder weather which could lead to more trouble.

[Crasher]

I spent a stupid amount of time repairing a heavily messed around with R32 turbo conversion harness and it drove me potty, I should have just bitten the bullet and fitted a new engine wiring harness and modified it to suit my new system, I would have saved myself a lot of discomfort and the customer a lot of labour line, mind that would only have dealt with the 40 pin plug, the other harness with the 81 pin plug is obsolete so I ended up doing all 100 or so wires (not all of the 121 pins are used) into new pins and new plugs, no wonder my back hurts...

[willdudeuk]

OH!! That is certainly a nightmare......

I think I could attempt an overlay harness.....just need to depin the buggers at the ECU....failing depinning at the ECU I shall have to fork out for the new harness.....

On the other hand I would hate to spend £300 on harness and then find out it's the ECU at fault...

Perhaps I should look at getting ECU tested first to safeguard against this? Though I am fully aware of your opinion of these ECU testing companies....it might not be worth it....


IF ECU and wiring are not at fault Crasher....what else would you be looking at next?

[Crasher]

I would have "borrowed" a genuine throttle body from TPS by now, if you spend thousands a month with them they do nice things like that. I would only plug it in through, just to test. If I still had the same fault and the wiring checked out end to end and the trace on the oscilloscope made sense, then I would be on fleaBay looking for an ECU, new ones are daft money.