1. Trisco palm scanner says "no car data" for sfi and bm systems, after new upper wiring harness installed. What does this mean? is lh moduel bad? are the wires bad?

2. If the two ground wires behind the headlights are broken, will they keep the car from starting?

3. After replacement of upper wiring harness the onboard push-button led dtc reader stopped working completely.

4. Home brew dtc scanner gave code 5 for pin 7 - can databus: message from ea/cc/isc module faulty (n4/1); message from abs/asr module faulty (n30/1); message from lh-sfi module faulty (n3/1). What does this mean?

5. Upon installation of upper wiring harness, I think I broke the camshaft position sensor. Will this keep my car from running as well?

Thanks in advance for the help.

Have you checked for power at injectors, ignition coil. The cam sensor is part of the system and tells the ECU the phasing of the engine - I dont think it would fire with it disconnected.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

I checked all the injector cables and they have power. Checked resistance on the injectors and they were all the same.

How do you check power at the coil?

OK, before this goes too far.

Were you able to communicate pre harness change?

Why was the harness changed?

Was the harness new / correct year?

For cars in general, a bad cam sensor will still allow the engine to run. Synching the computer with cam position syncs the injector pulses. This is done mostly for smooth idle.

Injectors are fired by grounding one side of the injector coil.

Any missing grounds are a possible problem as are dirty grounds.

Pull the ECU plug, key on then probe pins for power and ground . ( you will need a wiring diagram / pin out for this. )

From the symptoms it sounds like the ECU isn't being powered up. There is also a possibility that sensor power supply is being pulled to ground.

Palm scanner was unable to communicate with any of the systems except for the OP system pre harness change. After harness change i checked only sfi and dm systems. I will check the op system now.


After harness change homebrew tester doesnt work for any of the pins, the led lights up immediately when wire inserted into pin.

Harness was changed because everyone said its likely the problem and the old harness was completely in pieces.

New harness is dated 04, made for w124 400/420e.

I checked the lh module power supply preharness and it didnt show any power. I may have had power and ground on incorrect pins. I was told lh module should only get power when teh car cranks, is this correct?

Some other things happened after harness change:
- onboard led dtc stopped working, worked pre harness
- fuel and oil gauge dont move with key in start position, also worked pre harness

Let me know what you think I'm completely lost. Thank for the help.

Did the engine run preharness change and you only had a com problem?


With the key off, unplug the computer boxes and retest. If it lights up, the diagnostic line is being pulled to ground when it should be open.

" The problem"? Was it the lack of com or some other problem?


I'd have to see a wiring diagram to determine this, I'm giving general electrical diagnostics. I don't have specific knowledge of you car.


Based on diagrams I've seen , the onboard LED should at least light up when the button pushed. If not you are lacking power and / or ground.

On losing the fuel and oil gauge, I think the dash runs from the CAN bus so if the bus is down the gauges won't work.

You really need a wiring diagram to fix this.

Based on the way my 91 SL is built ( Vs the 97 ) there are a lot of eyelet connections that could be miss connected, perhaps the problem lies there.

Backstory:
4 years ago car was involved in minor front end collision. From the day of accident it sat at a shop until i got it back recently. Two weeks ago started working on it. I put in a new rad and fan, pulled core support and now am trying to get it running.

Since rad and fan were put in the car would only crank but not fire up. It would fire up with starter fluid, this was all before new harness was installed. Within the last week I've put in a new fuel filter, spark plugs and harness.

I have a real mbz dtc reader which gives me codes for the op and ea/cs/sci systems but shows 'no ecu control or no data' for sfi, ezl and di systems.

This is whats going on.

So you had car running pre rad change, then rad was changed and car quit running?

Did you fix the bad grounds in the headlight area you spoke of?

A correct wiring diagram is a must at this point, sniff around here for a diagram. If something is there, post the link and I'll have a look.

W124 Performance

DId the car run at all the first time you tried to crank it after sitting for 4 years? No-start conditions on M119s appear to be 1,000-piece jigsaw puzzles unless you have some clues or understand the basics of m119 behavior, so always start with the lowest common denominator, grounds bring one, ignition components being the other when the car has sat for so long.

My 400E ran fine until it sat under a cover for a mere 3 months, whereby the 2 year old caps and rotors became completely fouled by moisture. I'll say again, M119s do not like to sit, at all.

Also, one tiny issue (such as head/taillight grounds) can cause 3 dozen unrelated DTCs and throw every system downstream into seeming catastrophic chaos. One thing I've learned in 4 years and 2 M119s, it's almost never as big a failure as it seems. Start with the extreme basics first, and after sitting 4 years, all filters, caps/rotors, coils, plus wires and plugs need to be checked for moisture contamination

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former: 83 300D, 97 C230, 93 400E

current: 08 C300 Luxury , 92 500SL

If the replacement w/h wasn't compatible with your model, that would explain why . . . the PN is marked on the cable near the bend in the firewall.

Or possibly the correct w/h was installed incorrectly?

BTW, you have other threads going on the same problem. It's best to keep the info in one thread IMO.

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Regards . . . . JimF
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'94 S500 Cpe

Visit my Mercedes Web Page

When I rebuilt my harness, I noticed that the 92 harness was a different part number than the 93 harness, etc. In your earlier post, you mentioned that the new harness you have is for a 400e/e420. They are different part numbers. Could that be what is holding you up here?

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1992 400E current
1988 300E sold
1973 280C totalled
1973 280SEL never got it running
1971 250C my first love but rusted out