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Hi to all ,
I have an intermittent misfire problem mainly on cylinder 2 and 5 , when it happens the engine will vibrate like crazy , if I leave the car off for long hours it acts normally again for days but the DTCs come back immediately.
new spark plugs installed , O2 sensor number 1 left replaced and it cleared a short circuit DTC but the car is still working intermittently . Attached are the DTCs .
I suspect a bad ECU since i have an < ECU internal error > code .
kindly share your thoughts .
I can't keep troubleshooting without trusting that my ECU is good first .
so I am thinking of replacing it .
If no little mouse scratch the wiring harness, is it a good idea to make a software backup from your ECU and to wait for a good deal on ebay till you repeat the diag with a proper tool.
If no little mouse scratch the wiring harness, is it a good idea to make a software backup from your ECU and to wait for a good deal on ebay till you repeat the diag with a proper tool.
Yeah could be a wiring issue , ill get the ECU replaced , if its not fixed I'll start the wiring check on the components listed on the DTCs .
You did noticed most of your codes are HISTORIC is. not current fault.
How long foes it take to come back when you clear ECU Fault?
Have you inspected the ECU plugs for oil swamp??
Have you tried to reboot whole chassis by disconnecting all batteries for 15mn ?
Then scan data for live fuel pressure value near 60Psi.
Yeah I noticed once I clear the codes they come back on the same day .
Ecu plugs inspected
I removed only the negative battery terminal for more than an hour.
fuel pressure not inspected but why whould fuel pressure set a code for a faulty ECM ?
Yeah I noticed once I clear the codes they come back on the same day .
Ecu plugs inspected
I removed only the negative battery terminal for more than an hour.
fuel pressure not inspected but why whould fuel pressure set a code for a faulty ECM ?
.... why check fuel?
because you have multiple misfiring faults.
every fault coming back including "historic" that means unstable transient conditions.
.... why check fuel?
because you have multiple misfiring faults.
every fault coming back including "historic" that means unstable transient conditions.
yeah that would be a priority when I am troubleshooting a typical missfire issue , but when the ECU that gives this fault says that the ECU is internally defective that code would be my priority to fix , then I can rely on the other DTCs , however I will check the fuel pressure just for the sake of it , i tried to find the data in the scanner b4 but could not find it so ill just use a pressure gauge.
Finally solved the issue, I had multiple intermittent faults thats why it took a while .
1) Bad ECU
2) fuel injector 5 getts stuck intermittently
3) bad lambda sensor
4) vaccum leak from a hose
All fixed all okay now .
If I had a scan tool that could clone a used ECU i would have solved it earlier.
BTW anyone knows what is the cheapest Autel model that is capable of cloning a mercedes ECU offline ?
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