Suddenly stuck after hours...

[Knoxxio]

Have a 3.0CRD with a weird problem. After several hours driving with a quite high load, the car suddenly stuck with OBD injection low voltage errors (P0261....P07xx) on all cilinders the same. Without a high load it's possible to drive for days continuously. When it stucks, the only thing to do is switch-off, key out, key in and start. Then the engine and the car runs smoothly, only the engine light is on, meaning the obd-codes are not cleared, but after disconnect and reconnect the battery the light is off. The whole problem process is iterative. The main question is: "You do not know when it stucks again".
First the dealer had suffered himself on this problem for one week and couldn't come up with the solution, so the car were brought to the diesel garage. The garage and I did a lot. Tested and cleaned each injector, cable connectors, earth connections, changed the fuel filter, tested fuel pump, software updates except the mapping of the ECU.
Somebody else who had experienced such problem? Where to find a good electrical schematic?

[Kreso]

OK so we go. This is typical ECU (computer problem) Not mechanic or electric. To be simple, some component in the PCM is on its way out. Solution - replace PCM. With such kind of problem one never know when it will happen again.

[Knoxxio]

For me, I suspected also the ECU. But due to lack of a proper schematic I don't know how much current (Ampere) the output circuit must give. If this is high and it will increase the more power is needed, then it is feasible that it stucks after a while.

[suzieque]

I wonder if the sensor or plug on the fuel rail was defective? I know very little of troubleshooting the CRD, but I appreciate your diagnosis and updates.

[Kreso]

1. it is not necessary that amps are the problem. Problem can be just veak component in the ECU. Little bit of higher temperature, veak part cannot handle that and ECU hangs just as any other computer. Shut down the engine, restart and all is OK for undefined time.
2. Sensor cannot do that on the crd at least not without code.

[Knoxxio]

Suzique + Kreso,

Drove without problems 2000km continuously, so think my problem has solved. Waht did I? Hell of a job.
First build out the ECU and brought to ECU repairman. Static measuring of components, no failure, only one solder point was not so well, but unlikely that this gives problems.
Cleaned and washed C1-C4 connectors with Griffon CS90 then dry them for one day.
Re-assembled all and voilà.....working...

Warning: Contacts have made from manganese, so must be totally dry to avoid burning in.

[i0r15]

I've experienced various bugs with the WK. From traction control problems to startup problems. The funny thing is that the mother effer seems to fix itself.
Never had to take it in to the dealer for any problem what so ever.
If you have any problem, just give her some time and she'll come around when she's good and ready :lol:

[Kreso]

In a ECU that solder point can be a culprit of the problem. Meaning, when contact is good, no problem. When contact gets weak(temperature, ???) ECU hangs, problem is there. So by soldering the point can fix the problem

[suzieque]

Suzique + Kreso,

Drove without problems 2000km continuously, so think my problem has solved. Waht did I? Hell of a job.
First build out the ECU and brought to ECU repairman. Static measuring of components, no failure, only one solder point was not so well, but unlikely that this gives problems.
Cleaned and washed C1-C4 connectors with Griffon CS90 then dry them for one day.
Re-assembled all and voilà.....working...

Warning: Contacts have made from manganese, so must be totally dry to avoid burning in.

thanks for posting back, your solution may benefit someone else! :)

[Knoxxio]

Yes you could be right Kreso. My background was computer design and as hobby did a lot of repair on analogue tv, video and so on. Mostly bad contacts are fault triggers, but here it is not logical, because so less current flows through the ECU, but the output controls the C1-C4 and there is flowing 30-40Ampere. For my search I bought the Autel Maxiscan and recorded life data. The Maxiscan showed sometimes that the pressure was not stable. A willing dealer gave me the schemes and pointed me to C3. Problem with this diesel is that is has no limp mode due to a different ECU than the ML320 and that's why it stucks.
The new 3.0CRD of Fiat is better and and more sopisticated.