Another D2 Starting Problem

[jkempf]

First D2 2002 LHD V8 USA (Vermont)

Now that that is out of the way, I put a new/used starter in today. Battery looks to be OK but I am charging it more just in case. I looked at relays and fuses from the fuse panel lid before going to the manuals and wiring diagrams. The fuse box lids show several icons but none are labelled "starter" there are some labelled "PM" and some with the CEL logo. Now reading the manuals there are a lot of other components that might be involved in proving before starting. BTW, I searched for everything on starting I could find before starting a new thread.

What the truck is doing is as follows:

1. All lights are working, ignition is working but no starter turn at all, no solenoid click.

2. The lights and accessories go out as they should on turning the key to the crank position so I think the ignition switch is OK.

3. One single relay click on crank position but it is a relay in the cabin not in the engine bay. I think it is the relay that cuts out everything electrical while you are trying to start.

4. Grounds and fuses checked so far look fine.

5. I swapped what I thought were the starter relay with other same part no relays to see if it was that with no luck. Haven't jumped the relay sockets yet.

So my question is as follows:

1. What test can I do to the starter I removed and the new starter in place to verify I have a working unit? I have a 12v charger to use as a power supply and lots of jumper wires.

2. What about alarm or any other lockouts? Anything like that to check?

3. There seem to be a pile of fuses and relays in the starter circuits in the wiring diagrams. Relay R100, R102, R103... fuses 1, 8, 10, 12, 13 in the engine box... Inertia switch, body control unit, Fuel pump, ignition switch... fuse 23, 27 in the drivers kick panel for the ignition starting circuits... Any ideas there?

Last, for those in other threads that battled with the starter removal... I had no problem. Heat sheild out, remove both bolts and wires, pull starter (seriously light weight compared to my german stuff), put starter back in, never seize everything and put it all back together, 1.5 hrs. first time. Don't see the problem. It took a couple extensions but really it is an easy job compared to doing an alternator in my A6 by turbo which starts with removing the entire nose of the car...! This was an easy one. But anticlimactic.

HELP! Need this thing to become a moving violation again.

Jay K
Warren, VT USA

 

[mbrummal]

jump from the battery + to the wire that goes to the starter solenoid. It is a brown/red wire (IIRC) in the connector on the top of the fusebox (front left corner when looking from behind). The RAVE will tell you exactly which wire it is.

 

[jafir]

is the red security system LED in the gauge cluster: on, off, flashing fast, or flashing slow?

 

[jkempf]

is the red security system LED in the gauge cluster: on, off, flashing fast, or flashing slow?

No flashing lights in cluster. Not sure where it is supposed to be so not sure if it is on or off. Doors open and close with the key fob with no issues. This one has me stumped.

Jay K.

 

[jkempf]

jump from the battery + to the wire that goes to the starter solenoid. It is a brown/red wire (IIRC) in the connector on the top of the fusebox (front left corner when looking from behind). The RAVE will tell you exactly which wire it is.

Will do,

I am going to go back under tomorrow and look at the connections on that end too. I thought the battery might be acting up when it was down. Charged it a bunch more and it has lots of juice so I will start doing continuity checking in the AM.

Stumped.

 

[jkempf]

What's a Body Control Unit and where is it. It is the earth for the solenoid circuit...

Jay K.

 

[jkempf]

OK, found the BCU in Rave. So I should be able to bypass it if that is the issue. That's a last resort. Anyone ever have the BCU block the starter even when the car is unlocked and the alarm doesn't seem to be armed?
Just fishing for possibilities.

 

[jafir]

No flashing lights in cluster. Not sure where it is supposed to be so not sure if it is on or off. Doors open and close with the key fob with no issues. This one has me stumped.

Jay K.

Lock the door with the fob (or even the key, usually) and look at the gauges. You'll see a red LED start flashing.

OK, found the BCU in Rave. So I should be able to bypass it if that is the issue. That's a last resort. Anyone ever have the BCU block the starter even when the car is unlocked and the alarm doesn't seem to be armed?
Just fishing for possibilities.

You won't be able to bypass the BCU. Without it if you can even get the engine to start it will immediately die. But I wouldn't start there. I'd make sure you are getting power when you try the starter.

 

[jkempf]

Some more info today:

Battery held 12.5 V overnight so that is not draining down.

Jumpered pin 30 on the starter relay base to +12V and got starter turning so that part of the circuit is fine and the starter and big grounds are fine.

Looked at all the connections from the ignition switch back to the engine fuse box and everything is clean and tight.

There is a connector in the front left of the box as mentioned by Jafir. Actually there are two that pass all of the I/O to the box. Red/white from ignition switch, brown to relay, yadda plus others. So I understand the wiring diagrams now.

The only two things that could block starting are BCU and inertia switch but I think the inertia switch is only tied to teh main relay adn I am getting power so I think I am good there.

Question: With the engine off and the key in accessory, when I then turn to crank I should see pin 87a on the relay socket power to +12 if I have proper ignition switch contact, correct?

 

[jkempf]

And more info:

1. Relay is fine.
2. Ignition switched 12v to relay coil is fine. 85
3. 12v to starter solenoid pin at relay socket is fine. 87a
4. Put 12v jumper to relay socket pin 30 and starter turns.
5. Pin 86 back of coil to ground is megohms and if I try to put 12v to ground I get 5-6V. BINGO!

Is it possible that this thing has been immobilized? I am reading in the manuals about the 12 layers of immobilization and it reads like decending the scale of Dente's Inferno. Back to "The God's Must be Crazy"... "The Anti-Christ"... Iyiyiyiyiyiyiyiyiyiyiyiy....

How does one reboot the alarm to make sure it isn't intercepting the starter circuit in the BCU and blocking starting?

Or can one just put a parallel ground wire on that relay pin to a known good ground? Or will that freak out the BCU even more? Course I haven't actually started the thing yet so I don't know that I have fuel pumps working yet as I haven't turned the engine with the key yet.

Very confused in Vermont. At least it is none of the big wires. I am down to one Black/Orange wire between the BCU and relay socket.

 

[jkempf]

Ack!

The LED in the cluster is now functioning again. When I lock with either the key or Fob it flashes fast for a short time on locking and then slows down.

It is now looking immobilized. The manuals are not clear about LED flashing modes and what they mean. It does have a big list of modes.

 

[jkempf]

And as I suspected the starter interrupt circuit alone inside the BCU has gone Kapput. There is a single solid state relay built into that black box that interrupts ground to the starter relay coil. If it is out it means that the starter relay coil won't complete a circuit to ground meaning that you can't hot wire the car easily. That circuit is dumb and does not know it is not working so it doesn't throw codes or alarms and doesn't cause the rest of the immobillizer to work. So the BCU thinks it is fine but the starter won't work. And that is the only function of the BCU that isn't working.

The fix was to put a parallel ground on the black/orange wire from the engine compartment fuse panel 0573 connector to the nearest ground. Now it starts reliably and all the alarm functions appear to be working fine. I don't know why I always get these head scratchers. Must be a test. I did test the old starter with a battery and some jumpers and it was way dead so it took this circuit out when it died apparently.

Meanwhile a mouse decided to nest in the fan squirrel cage and I had to dig all that crap out and now the AC is blowing a bit cold on one side of the dash and warm on the other meaning the mixing flap is stuck plus I have a vacuum sound coming from about the left side of the stereo head when I start or shut off the engine. But the vehicle is running reliably now so that is minor stuff unless of course I have to pull the AC box to dig the crap out of it.