500E cranks but will not start
 

This is a '92 500E and I was working with the diagnostics and I arc'd from Pin 3 of the X11/4 to the CAN. The ignition was off. Now when I turn the key all the lights on a dash light except for the CE light. The engine cranks but will not fire.
I am getting Error codes that state no communication with the LH module.
Code 20 on PIN 4, Code 7 on Pin 7, Code 9 on Pin 8 and nothing on Pin 19. All these point to an open circuit. I've checked all the fuses I could locate. I'm hoping that there is one fuse I missed or something else before I consider bring the LH module in for service or replacement.
Any ideas?

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Check fuses on the top of the Base Module

I checked the 3 fuses (not 4) on the Base Module and swapped them out just as a precautionary.

Also after re-reading my thread..Let me make it clear what happened. I grounded pin 3 (+V) on the X11/4 to the metal module base. I got a small spark.

and the explanation of the codes are:
pin 4- code 20-No CAN data transmission from LF-SFI control module
pin 7- code 7-No CAN data bus signal from EA/CC/ISC,ABS/ASR,HFM-SFI or LF-SFI control module faulty.
pin 8- code 9-m104, 119 LH-SFI control module voltage supply, open circuit
pin 19-nothing, doesn't even tell me it's OK.
I've checked all the fuses I could find and before I start spending money on a module I wanted to see what else to check of if there is any more troubleshooting I can do.

Mark

Do you have power on pin 3 in the X11/4?

<<pin 8- code 9-m104, 119 LH-SFI control module voltage supply, open circuit
>>

You have blown power to the module

What ever made you ground a 12v supply ?????

Fuses #7 and 9

Trust me, it wasn't on purpose !!!
I was checking fixes to repair:
PIN 19 code 26 Upshift Delay faulty.
and when I pulled the cable off the x11/4 the pin grounded against the metal module. My BAD. But I was kinda surprised by the short , because the ignition was off. I assumed (wrongly) that since the ignition needed to be on to check codes, that there would be no power when the ignition was off.

And yes I still have power to pin 3, that's how I was able to pull these codes after my screw-up.

Did you check 7 and 9?

I inspected all the fuses in the panel and replaced #9 but I'll go back and double check #7.

I double checked all fuses again, replaced #7, and they check OK and no change.
I put a voltmeter on pin 3 of the X11/4 and to ground it reads 2.1V (?) with the ignition off or on.

The problem I am having is you have early Cal version .

But , I show BM fuse 7 and BM feeds N59.
And fuse 9 feeds N59 for power,

So, you may want to go to N59 and see if you have 12v at pin 4 [ rd/gy]

Check each side of both of those fuses w/test lamp, but on the fuse holder, not the fuse ends.

If you have 12v at pin 4 of N59 and No CE lamp when key is ON, I suspect the N59 module, not the Base module.
I also show 4 fuses on BM..but that is 93 schematic.

May want to check some grounds too, b/c you still should have 12v at pin 3 if fuse 9 is good. You can tell that by using bat neg instead of chassis ground. If you have your 2v w/chassis ground, but 12v using bat neg, then you have a bad ground [ brown wires]

First off let me say Thank You Arthur for all the help! You gave me invaluable help and assistance so far. Best troubleshooting skills training I've had in a long time.
This is what I found so far.
At fuse #9 with fuse removed I have power across the holder ignition off & on.
At fuse #7 with fuse removed I have power across the holder only with the ignition on.
On the display for the N59 the red LED is lit as soon as I turn the key ON. When I hit the button it gets brighter.
What I haven't found so far is the N59 module! I have 3 wires from the display to a connector that then goes down along the wall on the right side of the engine then I lose it. Nothing that I have talks about the location of the N59 so I'll have to trace it and see where the wires go.

Mark, N59 is in the right foot well, but I would not worry about it for now. It is a power consumer, not the source. I think you need to check your fuses again. To check fuses you need to measure voltage between the fuse holder and chassis ground. Measure on both sides with ignition ON. If the fuse is good you'll see same voltage 12VDC. If the fuse blown, you'll see 12VDC on one side and 0 on the other. Also, go back and double check fuses on the Base module. You need to check continuity on them as you can't get to the holders to measure voltage. Do not rely on visual inspection only. If you find all fuses good I'd suspect the Base module. Maybe burnt trace inside?
Mike

Went back and checked all fuses to ground and the readings are 12V, also checked for continuity on the fuses in the BM and they show 0V.
I did check the N59 at pin 4 I got a reading of 3.1V to ground. Pin 9 gave me 12V.
Mike I think your right that there is a bad lan in a module.
The LED on the X11/22 always being lit with the ignition being on is confusing along with a 9V voltage reading on pin 4 also on the X11/22.
The codes all show OPENS but this is looking more like a SHORT somewhere in a module.

OK, went through the fuses again and all check OK.
Reseated relays, checked wiring harness, reseated all fuses.
Opened the Base Module and didn't find anything obviously wrong.
Removed and reseated all modules.
Checked codes again and now have nothing on PIN 4.
I believe that it is the BM. ( probably the circuit that is protected by FUSE 2 ).
I'm kinda at a loss on how to continue. Does anyone know if there is someone that does diagnostics on the modules? Any recommendations on a shop that repairs them? Beckmann?
TIA