Ok so here it is,

Before the car went into Speedriven for more upgrades it threw a check engine light which showed misc. misfire on some cylinders, the light went away by itself and never came back for a month or so. The car is driven very rare and after I picked up the car I started driving a bit more because of the excitement. now the check engine light came on 2 times and both times it cleared after restarting the car and driving it around again. Weird part is that the second time it came on I was driving the car without being hard on it at all. The previous two times it went on I was on it pretty hard. The coil packs have been changed by the previous owner not too long ago. Anyone have any idea what could cause this? maybe its a simple fix? After the forum my next stop is back at Speedriven so they can check it out. I run 100 octane in the car now and from what I have heard these cars are very sensitive to fuel. Maybe a fuel issue?

Any help would be great.

Thanks

KAMIL

 

Pull the stored code and let us know what it or they are.

 

This. Get a scanner from a local autoparts store. That way you can pull the codes at least.

R.K.

 

Check your Coil Pack Part#'s with a flashlight..sticker ontop of the coil pack bar itself.. You'll need to pull the CF Cover off..
Let us know what they are.. to see if there are newer part#'s...

I had the same symptoms, it just gets progressively worse.. The Codes should verify it for sure.. Random PO300's..

I highly recommend anyone that you get new Coil packs with the "newer" part# if your going to get a "Tune" from anyone..
I wish the Tuners would give a heads up on that for M275 V12 Engines.. at least check it for you or ask you to check it..

I know, it's expensive but there is no point to tuning when you have the original coil packs with the old part#s.. with a tune, it's a fast track in getting new ones anyways.


After I put in a newer coils, and new spark plugs, it was like a whole nother car..beast.


If you have newer partno#'s on your coil pack, then I'd check if you have any evidence of oil accidently dripping down the path where the oil filler is.. if you miss by a tiny bit topping off the oil, the path leads straight to the spark plug cavities and soaks the red insulation boots.. My symptom was the old coil packs and the minor shorting that occurred at WOT caused by that old oil seep from the oil filler.. no actual oil leak.. someone just got sloppy filling it.. (after that episode, nonone touches the car but me now..

And yes, I checked and replaced all 24 spark plugs and red insulation boots myself.. even cleaned the spark plug cavities.. Simple green is your friend.

Not one CEL since.

 

Very true!

 

what are the new part #'s?

 

It was discussed here:

https://mbworld.org/forums/cl55-amg-...-tcu-tune.html

R.K.

 

P0140

 

Looks like a lot of things to test but its not a big deal. If you had to guess without testing I would replace the post cat 02 sensor. Most cars when you blow the 02 heater fuse it will effect more than one sensor and will set a separate code. It doesn't seem to be true here.

OBD Code P0140refers to

The Powertrain control module (PCM) will provide a .45 volt reference voltage to the Oxygen sensor. When the O2 sensor reaches operating temperature, it will generate a voltage that will vary depending on the oxygen content of the exhaust. Lean exhaust generates a low voltage (less than .45V) and rich exhaust generates a high voltage (greater than .45V). O2 sensors on a specific bank marked as "sensor 2" (as this one is) are used to monitor emissions. A Three-Way Catalyst (TWC) system (catalytic converter) is used to control tailpipe emissions. The PCM uses the signal received from Oxygen sensor 2 (#2 indicates aft of catalytic converter, #1 indicates pre-converter) to read efficiency of TWC. Normally this sensor will switch between high and low voltage at a noticeably slower rate than the front sensor. This is normal. If the signal received from rear (#2) O2 sensor indicates that the voltage has "stuck" between .425V to .474 V, the PCM determines this sensor is inactive and this code will set.
Symptoms

Possible sumptoms of OBD code P0140
Your check engine light(CEL), or malfuction indicator lamp (MIL) will be illuminated. There will not likely be any noticeable drivability problems other than the MIL. The reason is this: The rear or post catalytic converter Oxygen sensor does not affect fuel deliver(this is an exception on Chryslers). It only MONITORS the efficiency of the catalytic converter. For this reason, you will likely not notice any engine trouble.

Causes

Possible causes of OBD code P0140
The causes for a P0140 code are fairly few. They could be any of the following: Shorted heater circuit in O2 sensor. (Usually requires replacement of heater circuit fuse in fuse block also) Shorted signal circuit in O2 sensor Melting of harness connector or wiring due to contact with exhaust system Water intrusion in harness connector or PCM connector Bad PCM

Possible Solutions

This is a fairly specific problem and shouldn't be too difficult to diagnose. First, start engine and warm up. Using a scan tool, watch the Bank 1, sensor 2, o2 sensor voltage. Normally the voltage should switch slowly above and below .45 volts. If it does, the problem is likely intermittent. You'll have to wait for the problem to surface before you can accurately diagnose. However, if it doesn't switch, or is stuck then perform the following: 2. Shut off vehicle. Visually check the Bank1,2 harness connector for melting or chafing of the harness or the connector. Repair or replace as needed 3. Turn ignition on, but engine off. Disconnect the O2 sensor connector and check for 12Volts at the Heater Circuit supply and for proper ground on the heater circuit ground circuit. a. If 12V heater supply is missing, check the proper fuses for an open in the circuit. If heater circuit fuse is blown, then suspect a bad heater in the o2 sensor causing a blown heater circuit fuse. Replace sensor and fuse and recheck. b. If ground is missing, trace the circuit and clean or repair ground circuit. 4. Next, with connector still unplugged, check for 5 Volts on the reference circuit. If this is missing, check for 5 Volts at the PCM connector. If 5 Volts is present at the PCM connector but not at the o2 sensor harness connector, then there is an open or short in the reference wire supply between the PCM and the o2 sensor connector. However, if there is no 5 Volts present at the PCM connector, the PCM is likely at fault due to internal short. Replace PCM. ** (NOTE: on Chrysler models, a common problem is the 5Volt reference circuit can be shorted out by any sensor on the car that uses a 5 Volt reference. Simply unplug each sensor one at a time until the 5 Volts reappears. The last sensor you unplugged is the shorted sensor. Replacing it should fix the 5 Volt reference short.) 5. If all the voltages and grounds are present, then replace the Bank 1,2 O2 sensor and re-test.

 

I would let the control O2 sensors be coded-out from the ECU. Every tuner should be able to do this.

 

You can turn of rear O2 via star also

 

Thanks for that Information :-)

 

P0133 also came up on the reader

 

1) What is a good scanner to get, and

2) Is there a reference for all codes on the Internet somewhere?

 

+ 1,000,000 my SL has the latest Coil Packs too, it's night & day difference welcome to V12tt maintenance it aint cheap. Ask Speedriven if they'll have time to do it or another Indy shop (The Dealership coil bank's costs $1400 ea for part ALONE not installed & if you ONLY replace 1 side the other side will fail soon after, the older Coil Pack part #'s as mentioned above are inherently flawed, NEW parts are mandatory for tuned V12tt)

 

If all cylinders on one bank misfire and packs are new, it is ignition control module (the box just on top of the engine). I had 2 600s with this issue in the last year.

Igor.

 

^^Good to know.

R.K.

 

So I have recently been engaged to a NEW TO ME CL600 ...

I am in question to the Random P300 misfire codes...

I have done all spark plug and boots... after my spark plug job I noticed I had old part numbers...

the previous owner didn't want to touch the job with a 10 foot pole so

I bought the car knowing it needed maintenance and love...

the car was running rough with misfires on cylinders 7-12 and now I replaced that driver side coil pack with a new one from AUTOZONE !!! AWESOME PART COST @ 900 compared to 1400 or used at 750 on ebay..

I also got 200 in rebate cards gift cards... so I probably should of bought both like SPEEDRIVEN SAID SO...

I bought my OBD2 cable and am awaiting its delivery so I can run the codes with my laptop...

then I will let you know if its random mis fires in the other passenger side bank ...

very helpful owners with these cars...

Thanks guys...

I feel like I'm floating on a cloud when I drive this car... ...

 

my guess would be ignition module. most people replace their coil packs first and then find out it's the ignition module. are you still getting misfires?

 

It seems almost 50/50 as to whether the misfire cause will be the coil packs or ignition module. We already know the coil packs are iffy after a decade so I was glad to get in on the AutoZone promotion and there's a $600 rebate card coming

It still needed the ignition module which I got new on ebay for $775 shipped. That solved all misfire issues and I know the coils are good for another decade. People usually recommend parts.com but the reviews of that site are so shady we were willing to pay more to avoid any potential fiasco.

After doing the coils, the 5 minutes to do the ignition are a walk in the park!

 

well my codes are only down to cylinder 3.... I can remember trying to gap 1 spark plug
from .040 to .030 and I flattened the platinum conductor just slightly .... maybe its that little guy... but the code checks and then after two starts its gone again... its cylinder 3 for sure ....