~CL500~

CL Family,
I thought I might share an experience I had with my CL500 recently, document some symptoms and a resolution. Upon exiting the parking lot at work, my car abruptly stumbled (kind of like a 1st to 5th gear change at the wrong time). Check engine light (CEL) illuminated and the car would severely hesitate on acceleration and was shifting poorly for at least two weeks earlier. Upon further inspection from my OBD tool, the following codes were registered:

P0100 - Mass or volume air flow circuit
P0221 - Throttle/pedal position switch B circuit range/performance
P0130 - O2 circuit, bank 1 sensor 1
P0150 - O2 circuit, bank 2 sensor 1

Of the 4 codes above, only the MAF triggered the CEL (officially at least). The rest were pending codes. My accelerator pedal was on its way out and the O2 sensor alerts are likely due to the faulty MAF.

I bought a new accelerator pedal module for $165 from my local stealership (essentially an electronic gas pedal). The poor shifting is long gone now and the car shifts very smoothly, even with the bad MAF. After conducting some research, a faulty accelerator pedal module sends incorrect information to the transmission and ECU regarding throttle position, thus triggering these symptoms. It still exhibits some hesitation while accelerating from a standstill, but this is likely due to the faulty MAF. I attempted to clean it using MAF cleaner, but no dice. Thankfully I found a new in box OEM MAF on eBay and should have it installed by the end of the week.

I'll then clear the codes, drive it a bit, re-check for any pending codes and post the results.

AMGTestDriverNJ

interesting, keep us posted.

~CL500~

I just installed the new MAF, reset the CEL codes and took it for a spin. The car runs smooth as silk now. It almost feels new again.

Slam dunk!

awdrock

Awesome CL500!

I'll try the same thing you did and report back. Hopefully it will not also be the MAF!

I have a 01' S500 experiencing the same problems. Hesitation on acceleration, and it feels like a SLUG when I put the pedal to the metal! It just feels like its in the wrong gear slowly accelerating at any speed. Yours did the same right?

~CL500~

Yes; My symptoms were similar. Before you change anything, lookup the OBD codes you have current or pending. Then go from there.

awdrock

Changed the pedal, and the beast is back in the soul!

~CL500~

Great!

awdrock

I meant the soul is back in the beast

lilliandearden

2004 c320 wagon 56,000 miles. have replaced 2 maf's. Dec. 2011 and Oct. 2012

car stumbled June 2013 transmission shifting slow car jerks and bolts while trying to shift . shifting is really slow. . am told i need an electronic transmission control box which i must sign for... a statement that it is not lost or stolen before it can be ordered. very expensive. can anyone shed some light on this could it be only the accelerator pedal module?? thanks

biker349

check codes. could be accelerator pedal, but that should throw a code.

ctravis595

although i've personally had a transmission control unit fail, i've heard they rarely ever fail

instead it's more likely you're 13 pin connector on your transmission has developed a leak and now transmission fluid has made it's way into your TCU

it's possible your TCU is fine after a good cleaning with electrical cleaner and a servicing of your 13 pin connector

tommyosmena

cool wheels i ever seen here on forum

Kemuhkuhl

Good evening everyone. Long time lurker, first time poster. I've come to appreciate deeply the wealth of wisdom on this site.

A slightly different experience I thought might be worth posting and since this was the highest relevant forum post that appeared in the search >W215 P0221. I though I'd tag on here. If it belongs somewhere else, please jump in and let me know.

Hit 90K this week on the 2003 CL55 with no real issues. Good preventive maintenance compensates for a lot of sins.

Noticed I was getting a lag on shifting from the bottom end for about two weeks and finally experienced the "drag" pulling from the stoplight many others have commented on Friday.

No "Check Engine Light" or codes using an OBD II scanner. I have access to a Xentry and in retrospect had wished I had waited to se what it popped up with but I was eager.

MAP cleaned, no identifiable vacuum leaks (was told by my pocket MB pixie a vacuum leak would be instantly noticed), and throttle body sensor appeared within specs assuming I had the right volts/ohms/pins reference.

Performed the pedal reset much discussed in many threads on Saturday. On start up the shifting lag and limp seemed to be resolved. Drove about 40 miles through street traffic and warmed the engine, pulled into the garage and checked fluids (if you have ABC you know why).

Sunday, I went out to fuel up the fleet (Sunday ritual) and hadn't even made it from the driveway before RPMs were noticeably out of range (high) and the engine surged intermittently. Got the "Check Engine Light" and went into limp mode with the "EPS" soft warning on the dash. Pulled it immediately back into the garage and scanned getting the following codes:
1: P0507 Idle control system RPM high
2: P0507 Idle control system RPM high
3. P0221 TPS/Pedal position/sensor/switch B circuit Range /Perf

I think the ECU was doing its best covering for the Pedal switch/sensor and if I hadn't forced the adaptation, it wouldn't have ever popped the codes or been much slower in doing so. Don't know if this is a reasonable conclusion or if the adaptation was coincidental to the failure but I think it's worth considering.

New pedal assembly on the way.

ctravis595