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Hi everyone, I had to put this aside for major surgery. I'm back on it now. The latest is the car is throwing codes P0030, P0050 (Heater circuit codes) and P0300 - P0304 (Misfire codes cylinders 1 - 4 on the passenger side). I got into the passenger side engine harness and found the cluster of red wires that look to me to have shorted at the left end tip shown in the attached photo. I'm wanting to verify if this look normal for this harness or if this indeed looks like something shorted? I also include a photo of the underside of the harness "casing" that looks to be somewhat melted to me. I appreciate any thoughts. Thanks.
We have made some progress stay put for results
A wasted harness insulation causing shortcircuit...
FYI: feel free to read other chassis forums (w212) where your engine is featured... a lot of the control electronic modules are shared besides specifics to topless coupes...
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You need keep your battery charged up with a float-charger... else disconnecting battery is an excellent practice for extended sleep periods.
🙏
Last edited by CaliBenzDriver; 04-11-2023 at 12:53 PM.
Reason: battery must be A-1 ready
We have made some progress stay put for results
A wasted harness insulation causing shortcircuit...
FYI: feel free to read other chassis forums (w212) where your engine is featured... a lot of the control electronic modules are shared besides specifics to topless coupes...
----------++++++++------------
You need keep your battery charged up with a float-charger... else disconnecting battery is an excellent practice for extended sleep periods.
🙏
Hi CaliBenzDriver, recall our discussion related this thread, you suggested I check voltage at the engine harness splice where my harness looks burned. I checked it with the engine not running and the key in the "on" position. I am 12.48 volts at the splice. I checked the harness splice with the car running and it's getting 14.1 volts. Seems no fuse blown. Please let me know if you have any other suggestions. Thanks.
Last edited by hgoodwiniii; 05-11-2023 at 03:41 PM.
Hi everyone, I got a chance to work on the CLS 550 today.
Here is the latest
I did verify that I am getting power to 3 of the 6 cavities on the female side of the driver side and passenger side upstream O2 sensor connections while grounding the test light on the engine. I also verified that the fuse related to the upstream sensors is #57. The test light lit very bright on one cavity, not as bright on another and very dim on the3rd one that had power. However, I was able to verify that there is no grounding in any of the upstream cavities. Is this normal? I'm thinking I really need to get my hand on a wiring diagram
I did verify that the ECM has a ground on it. I put my test light on the ecm body and the other side on a hot fuse and it lit up
I sent the ecm for testing and was told there were no hardware issues found with it
I did not get a chance to test +12 on the SAM or the fuse #57 under load. Needed a helper for that. .
I appreciate any thoughts. Thanks.
find out that fues #57
Okay, we went into exploring the splice that has now tested good as well as alternator voltage at the splice itself.
So now I think it's back to where we were, focussing on testing the 02-Upstream harness. (sensors are already new genuine MB).
Last edited by CaliBenzDriver; 05-11-2023 at 05:59 PM.
Okay we want into exploring the splice that has now tested good its3lf as well as alternator voltage at the splice.
So now I think it's back to where we were on testing the 02-Upstream harness. (sensors are new genuine MB).
Ok, agreed. I been trying to find which pins to test on the 02-Upstream connectors for power. No luck finding any info on that. If I recall correctly, the connectors have 6pins. Any ideas on which to test for power? Thanks very much;
Here's the latest on the CLS 550 problem-
Here are voltage measurements I took voltage of the upstream 02 sensor plugs with the key in the "On" position
I'm not sure if these values are within the required ranges but seems that power is getting to the sensors so I'm not sure where to go from here. Seems there is hardly any information available to verify these values are good. It may be time to just give in and get the car to a repair facility. I appreciate any thoughts. Thanks.
Last edited by hgoodwiniii; 06-18-2023 at 11:32 AM.
Here's the latest on the CLS 550 problem-
Here are voltage measurements I took voltage of the upstream 02 sensor plugs with the key in the "On" position
I'm not sure if these values are within the required ranges but seems that power is getting to the sensors so I'm not sure where to go from here. Seems there is hardly any information available to verify these values are good. It may be time to just give in and get the car to a repair facility.
I appreciate any thoughts.
Thanks.
You've got to use a diagram.... usually power is feed directly from F-SAM FUSE and controlled by the ECU from the GND side with pulses (PWM). Meaning showing +12 is hardly a complete test.
i everyone, the car is in a German Auto shop here in town. They have confirmed that they are pretty certain that my ECM is bad in the CLS 550. They are quoting ~$3600 for a replace ECM with 1yr/12,000 mile warranty. I'm trying to figure out where to go from here. Can anyone provide a good source (with more reasonable price) for a replacement unit? Thanks.
Current codes (pulled by the shop) are:
(P1337) [Stored] Alternator serial interface
(P0228) [Stored] M16/6 (Throttle valve actuator) : Throttle valve jamming (iced up) (P0638)
(P0443) [Current and stored MIL] Heating of component G3/4 (Right O2 sensor, before TWC [KAT]) : Open circuit (P0030)
(P0447) [Current and stored MIL] Heating of component G3/3 (Left O2 sensor, after TWC (KAT)): Open circuit (P0050).
(P0217) [Stored] M16/6 (Throttle valve actuator) : The throttle valve is jamming or is stiff. (P2176)
(P0632) [Current and stored MIL] Misfiring (P0300)
(P0644) [Current and stored MIL] Misfiring of cylinder 4: Worsening of exhaust emission values after engine start (P0304)
(P0656) [Current and stored MIL] Misfiring of cylinder 3: Worsening of exhaust emission values after engine start (P0303)
> The throttle codes are all stored ie. currently no problem. This us ECU saying mixture has way too much air. 100% ignore.
When you look at the faults you realize the only issue is with the O2 HEATER Circuits.
> The misfiring is directly caused by un-heated exhaust sensor requesting lean mixture. 100% ignore for now.
only 2 significant issues.
The only thing that needs to happen is focus on the "Lambda/O2 heater" circuit.
-- Perhaps shop did use a scope to test and diagnosed a bad "control side PWM voltage" coming from the ECU.
-- Perhaps its just a poor GND circuit connection for ECU.
-- ECU is definitely involved in the O2 Heater control, does not make ECU bad.
the central issue...
I give this only 5% likeliness of bad ECU... unless specific ECU circuits were tested to be confirmed defective.
These two distinct separate circuits share GND and power. Both ECU transistor can NOT go bad together.... unless somebody got happy with welding arc machine on mufflers.
Last edited by CaliBenzDriver; 08-01-2023 at 02:12 PM.
Ok, yea this is a duzie. I'm thinking of just replacing the ECM to at least eliminate it. Anyone here know anything about these Computer Exchange (https://carcomputerexchange.com/) folks?
The main issue is that I can't seem to locate the appropriate diagrams to identify which circuits need to do what on the heater circuits plugs. Really, seems that since this is a heater circuit issue, my only options appear to be replace the engine harness or the ECM? The upstream sensors have been changed.
One other note is that my Foxwell says P0050 is an upstream sensor. The reader the shop is using is saying P0050 is a downstream sensor
Ok, yea this is a duzie. I'm thinking of just replacing the ECM to at least eliminate it. Anyone here know anything about these Computer Exchange (https://carcomputerexchange.com/) folks?
The main issue is that I can't seem to locate the appropriate diagrams to identify which circuits need to do what on the heater circuits plugs. Really, seems that since this is a heater circuit issue, my only options appear to be replace the engine harness or the ECM? The upstream sensors have been changed.
One other note is that my Foxwell says P0050 is an upstream sensor. The reader the shop is using is saying P0050 is a downstream sensor
Your thoughts?
Replacing the computer is a different rabbit hole than the one I'd go down to...
"Alldatadiy dot com" and other online providers have live electric diagrams a minute away and help info on tap for $20.
Code translation differences:
Up or downstream sensor is a minor issue on the scale of things.
What's involved is the heater side of these two separate circuits.... to me is a signature for poor GND connections.
🤞
Here is the latest. I went ahead and sent the ECM for testing since the auto center here in town kept saying they were confident the problems I am having are related to the ECM. I sent the ECM to Car Computer Exchange (never heard of them until recently). They came back and said components 4, 5, 6 and 7 are causing the issues I am having. They stated that they cannot repair the unit and do not have any in stock for sale. With that said, I want to just find a replacement. Anyone have any recommendations on a good, reliable reasonably priced source for an ECM? Thanks.
03-30-2023, 10:03 PM
