ECU - Short Circuit to Positive -> What does it mean?

[ibestriker]

Hello experts,

I have sent my ECU to German for repair. When the ECU has been repaired and returned, I asked my Merc Specialist Mechanic to install the ECU.

But there is an error sounds like this:

"IFZ: Short circuit to positive"

What does it mean? Does it mean the ECU is still faulty and not fully repaired? Or is it something else?

Because of that error, the engine won't start, there is a response of the engine sound though, but the red and green LED on the rear mirror keep blinking. The car doesn't want to start.

For your info, my car is W202 C-class year 95.

Hope to get some advices and recommendation.

Many thanks in advance...your help is highly appreciated.

PS: I missed my car, almost 2 months not working.. :(

[ibestriker]

Anyone expert pls help...:(

[jnenad16]

did you have the same problem before you sent off the ECU for repairs? if so, you most likely have a short somewhere in the harness, and judging by the year of your car, that would be the most likely culprit.

nenad

[ibestriker]

Originally posted by jnenad16
did you have the same problem before you sent off the ECU for repairs? if so, you most likely have a short somewhere in the harness, and judging by the year of your car, that would be the most likely culprit.

nenad

Hi nenad. Thanks for your reply.

Before I sent off for repair:
- Engine can start
- But engine vibrating because only 2 cylinders work

After repair:
- Engine cannot start
- When try to start the engine, the red and green LED
on the rear mirror flashing alternately

Short in the harness? Do you mean, the ECU is ok and not faulty? How about the wiring, actuator and coil?

Do you have any idea?

Thanks...in advance...

[jnenad16]

hm, it hard to tell without seeing the car myself. when you sent the ecu for repairs, did they inform you if they have found the problem and what it was? they defiinitely did something wrong, or repaired it by using wrong diagrams(for another model).
its probably best you contact them, and most likely they will either take back the ecu and attempt to repair it for free, or replace it with another one.

nenad

[ibestriker]

Originally posted by jnenad16
hm, it hard to tell without seeing the car myself. when you sent the ecu for repairs, did they inform you if they have found the problem and what it was? they defiinitely did something wrong, or repaired it by using wrong diagrams(for another model).
its probably best you contact them, and most likely they will either take back the ecu and attempt to repair it for free, or replace it with another one.

nenad

Yes they told me they have found the problem and the problem could be fixed.

Some said, maybe it is not the ECU that is faulty, I think some analysis has to be done..

[martattack]

I agree with Nenad. It sounds a lot like the engine wiring harness. It was shorting at the coil pack most likely before. That would let the car start but it would only run on fewer cylinders. After removing the ECU, it could have damaged the harness more, which is now causing the ECU to short.

That is my educated guess. Have you or your mechanic inspect the wiring harness. Probably a good chance that the insulation will be flaking away underneath the black tape wrapping.