C300 Cylinder 1 misfire
DTC (2) Count
0632 Combustion misfiring has been detected.
0636 Combustion misfiring of cylinder 1 has been detected.
These codes make no sense to me, there's no letter in front of either one. But the problem definitely feels cylinder related. Did I get a bum scanner??
If you have a CEL due to misfires and it is NOT flashing, you can continue to drive until you get to a shop. If it is flashing, you have a more serious problem and should not drive. Of course, being safe is most important.
The check engine light was yellow and non-blinking but I got a tow back to the shop and bonded with the driver for an hour.
Still wondering about those weird fault codes though. Does MB have MB-only codes and if so where can I find the list?
"The trouble code P0632 can be defined as Odometer Not Programmed – ECM/PCM. This fault code would start appearing when the powertrain control module would not be able to read the odometer."
"P0636 means there is an electrical error in the power steering control circuit due to a faulty sensor, faulty CAN bus, or other wiring issues."
I will double check in XENTRY to see if the definitions are different.
EDIT: 0632 and 0636 do NOT show up under the ECU. The only misfire codes are P030X.
CORRECTION: 0632 AND 0636 DO show up exactly as shown. I was looking at codes for the ECU in my SL400. When I switched to my C350, they were there. Also, no "P" prefix.
Last edited by JettaRed; Feb 24, 2024 at 07:29 PM.
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"The trouble code P0632 can be defined as Odometer Not Programmed – ECM/PCM. This fault code would start appearing when the powertrain control module would not be able to read the odometer."
"P0636 means there is an electrical error in the power steering control circuit due to a faulty sensor, faulty CAN bus, or other wiring issues."
I will double check in XENTRY to see if the definitions are different.
EDIT: 0632 and 0636 do NOT show up under the ECU. The only misfire codes are P030X.
CORRECTION: 0632 AND 0636 DO show up exactly as shown. I was looking at codes for the ECU in my SL400. When I switched to my C350, they were there. Also, no "P" prefix.
Last edited by JettaRed; Feb 24, 2024 at 11:31 PM.
0629 cylinder misfire
0633 cylinder 1 misfire: damages TWC
Took surface streets on way home, stayed at about 35 mph. The CEL did not come on until the last leg when I have to go up a fairly steep hill. The minute I pressed the accelerator to climb the hill the CEL came back on.
What Is my mechanic missing here? This problem only surfaced after new intake manifold installation. Mechanic says a faulty vaccum hose has been replaced. That did not fix the issue.
Last edited by Aging C300; Feb 25, 2024 at 03:24 PM.




0629 cylinder misfire
0633 cylinder 1 misfire: damages TWC
Took surface streets on way home, stayed at about 35 mph. The CEL did not come on until the last leg when I have to go up a fairly steep hill. The minute I pressed the accelerator to climb the hill the CEL came back on.
What Is my mechanic missing here? This problem only surfaced after new intake manifold installation. Mechanic says a faulty vaccum hose has been replaced. That did not fix the issue.

It seems logical because the engine ECU is missing combustion feedback.
your Lambda input is flagged bad by ECU
Have a reading of what it says above your misfire faults.
The ECU is disatisfied with the lambda circuit. What is really wrong: old sensor or chassis harness (/pin /oil)
ECU also flags an "intake air leak" which may just be standard way to complain for a lean engine.

It seems logical because the engine ECU is missing combustion feedback.
your Lambda input is flagged bad by ECU
Have a reading of what it says above your misfire faults.
The ECU is disatisfied with the lambda circuit. What is really wrong: old sensor or chassis harness (/pin /oil)
ECU also flags an "intake air leak" which may just be standard way to complain for a lean engine.




Back to the intake manifold repair being a source of air leak.
The shop told me since the vacuum hoses have been checked and nothing turned up bad they swapped ignition coils and tested sparkplugs which are good and still get the cylinder 1 misfire code. They said when they replaced the intake manifold they redid the fuel injector seals so they are going to make sure they are okay. Then I guess the next step is checking the fuel injector itself -- I hope it is something that can be cleaned and tested before having to pony up for a replacement. Not sure where the oxygen sensor goes in the order of potential issues to check. Again, we are at 134K and hoping to make it to 160!
Meanwhile, some "data" that may help: while driving calmly on surface streets the CEL does not come on. The magic number is 3000 RPM -- that's when the CEL pops on. If you turn the ignition off and restart -- no CEL until 3000 RPM reached by revving, accelerating while merging or going up a hill.
It is very odd. Does anyone replace all the ignition coils at once or wait for a fail?





