UrS4boy

There was some a discussion about the impact of a J219 "back-up (light)" relay on the ability of an UrS to start. I had previously did a little documentation of the Central Relay panel (above the Driver's side knee bolster) and knew about a relay in position 4 on that relay panel that was called out as the "Starting Interlock Relay" (see below). Initially, I had assumed that was for the automatic cars, i.e. you have to be in Park or Neutral before the ignition switch will energize the starter when the key is turned to START). The question was if the manuals don't have that relay per se but they have a "back-up light" relay, why does it seem to be involved in the starting of an UrS with a manual transmission? I had also documented that some ROW (rest of the world) UrSs did not have the "back-up light" relay but had a jumper instead. Based on that "back-up light" relay thread, I decided to investigate further.



Relay in question is the "204", in Position 4, third from the right (this is my 93 UrS4s central relay panel when I was running an older V8 "215" fuel pump relay instead of the normal "208"):



I first checked the Bentley and found the relay and its connections spread over at least three electrical pages. Hmm..not easy to document. Then I checked the FAQ and found a generic 1996 A6 quattro starter diagram that Nate P. (ImQuattro) had posted. I printed that off and then annotated it based on the Bentley. The result is this:



Where I have labeled "Track 424, PG. X84" on the right side of the diagram above, there is a connector symbol that I didn't initially think to pursue. In fact, that connector is the T6ac, a white connector in Connector Station 2, passenger side kick panel area. The Red/Brn wire is in Position 1/6 in that connector. Can be important in some situations. Like not starting (LOL).

Here is the connector in question (Note: The red/brn wire *is* in position 1/6; there is a red/gray wire going to 2/6 that shows more in the photo). What might be more important is the source of that red/brn wire as pin "T16/1" in the Central Locking and lamp control module (in the central locking pump, beside the battery, in a foam box, under the rear seat). More on that a moment, first that white connector in the passenger kick panel:



Okay back to the "T16/1" source of that red/brn wire. Look at the C4 Central Locking Diagram below. Scan down the right side in the T16 "C" connector pin-out (4th wire from the bottom). There it is, Pin T16/1 = "To starter relay" DING!. That's our baby!!



So based on these diagrams, my interpretation is that *IF* the Central Locking/Alarm System control module is happy with the situation (e.g. no alarms), it energizes the J219 which pulls the connection between 17/87 and 19/30 closed. As a result, when the ignition key is turned from OFF to START, current from the ALWAYS HOT No. 30 bus flows through the ignition switch, through the J219 (Pins 19 to 17), down the black "50A" wire to the "50" terminal on the starter solenoid. The starter solenoid, in turn, energizes the starter motor (which is wired directly to the battery) and presumably, the engine starts. (Well, unless there is another issue). BTW: This becomes an advantageous potential location for a very effective immobilizer system.

Now, *IF* there was an issue with the central locking module or the J219, then it would still potentially be possible to start the engine by removing the "204" J219 and jumpering positions 17 and 19, as shown with this factory "7" (shaped) jumper from a ROW UrS. A home-made jumper would be 2 spade connectors on the end of about 1.5" of 12 or 14 gauge wire.



In a pinch, if you had to over-ride your J219 "204" starter interlock relay, you could remove it, and replace it with a jumper made out of two male spade connectors at the end of a 2.5" (or so) length of 14 gauge wire, connected across the J219 socket in pin slots 17 and 19 (like the photo above).

Here is such a two spade jumper used to replace the 204 "J219" relay (in an emergency):



So where are the back-up lights in this story? Not sure, maybe on that S3/50A branch. Doesn't matter. What doesn matter is it appears that we have a form of starter interlock/imbolizer that prevents starting if the central locking system isn't happy for any reason.

Now I was curious about the "204" and its PN history and where the automatic interlock relay was in all this. It the central locking control module controlled the "204" starter interlock relay, where was the "Park" and "Neutral" override inputs going to come from?

First I had a look back at previous my Central Relay Panel post and found a photo from Popdemonic in Thailand that I had labeled. Where our manual transmission UrS4s/S6s would have a "204" Pop had a taller (double height) "369" relay. Hmmm...was this the clue?



Okay, needed to call out the big guns. I started by pulling my 204 "J219" relay to get the PN, 431951253H:



Then I asked my friend Kate about the 431951253H "204" relay. Initially she said "Huh? No such animal". When pushed harder, she revealed that the PN 431951253H "204" relay had been superceded to a 141951253B "53" relay on Sept 30, 1997, i.e. after the last UrS6s were built (so all UrS4s and UrS6s should (manuals) should have had a 204 leaving the factory) When asked about the 141951253B "53" relay, she revealed that it had been superceded to an 8D0951253A "373" relay. This succession is shown in the diagram below.

While talking to Kate, I noticed the listing for the automatic relay, i.e. 4A0951253 double (height) relay for position No. 4 for the automatic transmission cars. "DING!". A search on 4A0951253 revealed that it is a "369", just as shown in Pop's relay panel.

So, I conclude that, for the autobox cars, there are two feeds to the starter interlock "369" relay: one from the central locking pump (i.e. won't start if the alarm has gone off, etc) and one from the transmission shifter system (i.e. needs to be in neutral or park to fire the relay). Finally I have it figured (I think?) Could it be?



As a result of the above, I have revised the initial Central Relay Panel PN call-out table:



I've also updated the Central Relay Panel post:

C4 UrS Central Relay Panel (Under Drivers Knee Bolster ) PN callout

That was a lot of work. Done for now.

S6Raptor

So you basically just taught us how to hotwire our own car? lol. Or, theoretically...someone else's. It is kind of preturbing that the locking system interrupting the ignition sequence if it isn't happy, as it is meant to do, can be so easily overridden. Of course, one would have to have this knowledge beforehand and have specifically targeted a urs4 or urs6 for whatever reason.

UrS4boy

Not really. This info only gets around a problem with the central locking control module or the "204" J219 starter interlock relay.

You would still need a key to turn the ignition and disarm the steering wheel lock (I could show you how to do that too but *THAT* would be irresponsible. The current info would just help legitimate owners with keys from having to have their cars flat bedded home or to a shop to be diagnosed and repaired.

UrS4boy

BUMP: I just totally revised the original post in this thread with info that I learned on the weekend helping an UrS4 owner in the UK get his non-starting 93 UrS4 avant started (it was an aftermarket immobilizer messing with the OE starting (and starter-interlock) circuit(s).