Update:

I got an Actron code reader CP9580A from the local Autozone and I was able to check the code again ("P0120 Throttle/Pedal Position Sensor/Switch A Circuit Malfunction - pending") and erase it. After erasing the code, shutting the engine off and starting again, I was able to drive without an error - until I shut off the car again.

I will be checking out the following next:

- Throttle voltage sensors
- MAF sensor
- Engine wiring harness (maybe it has a short somewhere)





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Hello again,

I am hoping that someone on the forum will be able to help.

It has been several weeks (months actually) I have been trying to figure out the ESP Malfunction.

Based on the code P202E (which lights up "check engine"), I had the throttle body replaced. I also had the brake light switch replaced and the accelerator pedal (brake light switch was replaced as a "prevention measure" because it is often involved in ESP error based on the posts in this forum and the accelerator pedal was replaced because I had a code once pointing to the sensor in the acc. pedal unit itself).

Note that ESP error is intermittent - on stubborn days like today, it comes up every time I start the car. On other days, it does not come up at all. It came up on colder days and warmer days so temperature (outside) does not seem to be a factor.

When the car has the ESP error, it can drive up to 30mph and then it starts to brake abruptly, as if trying to correct for "slipping" of some sort. I don't know if this is standard behavior or potentially a hint that acceleration sensor or any of the speed sensors is not working properly.

I had the code cleared at the indy shop twice already and the car runs fine (without the error) after that but then at some point the error comes back.

The error code I am getting is P202E (see attached), pointing at the throttle body/actuator. I have tried to perform reset with the steering wheel (left, right and center) but that did not help.

At this point, I need some pointers what to look at next. Based on what I read in technical manuals, there are several sensors which "drive" the behavior of the throttle body and the actuator: pressure sensor and the "accelaration sensor"

I have never had any codes related to pressure sensors or the acceleration sensor.

Any help with debugging this would be greatly appreciated.

I am also looking for an OBD2 scanner which can clear codes. Which model can clear the ESP code?

S.

 

Put the car in "dyno mode" to disable
Esp and see if esp stays off allowing you to drive the car

You won't have the safety features of esp but you should at least be able to drive the car that way

 

also a faulty wheel speed sensor is a common cause of Esp problems

 

How can I troubleshoot wheel speed sensors?

What is very confusing is the P0120 code which points to the sensor inside the accelerator pedal assembly - or does it refer to some other sensor?

I tried the dyno mode and unfortunately it did not help. I did notice that, while in dyno mode, voltage is reported as 12-12.7 volts which appears too low. It should be at least 14V. This is why I suspect voltage regulator. If it was the alternator, battery would have drained by now because I am driving the car daily in spite of these issues.

What is particularly unnerving while in ESP error "mode": car can accelerate up to 35mph but then it starts braking very hard. I feel the brake action on rear wheels in particular. I am not sure if this is "normal" ESP limp mode behavior. It does not occur when I clear the error.

 

i believe low voltage can cause this. have your battery checked.

 

voltage is ok (14V) when car is running (measured with a voltmeter - is there a way to get the voltage reading in dyno mode while car is running?) but I found out that the alternator is putting out only about half the power (68 amps). since the voltage regulator is built into the alternator, I will have to replace the alternator.

I am 95% sure this is going to fix the esp malfunction.

 

Wheel speed sensor replacement solved my similar problem.

 

I wil have the mechanic check the wheel speed sensors this week. It is on my list. thank you.

 

All wheel speed sensors are functioning correctly.

I have found out that "brake pressure switch" (widget on the ABS module) is not functioning properly so that will be replaced first.

At first I found a Bosch AL0818X alternator which is listed as a fitting part for 2003 CL 600 but actually does not fit my car. Is it possible that CLs have different equipment at this level (alternator)?. Fitting part will arrive from MB because I did not want to get a rebuilt part. I have had enough headaches already.

 

Well . . . it's been months now, what's the latest?

 

Sorry about delayed update. The culprit was the ESP module itself so I had to have it replaced. MB Dealer matched the online price for the part (because I am a good customer so in the end it wasn't that expensive in terms of cost.

The worst part was the debugging but at least now I know that everything is in top shape lol

 

Who had the best online price for the module? And how much? Information is good!

 

Hello again,

I use mymercedesparts.com as a baseline for pricing - since I am a good customer, dealer in St. Pete was happy to match the price. ESP module costs about $1600 online. Part number is A 220 545 35 32.

The issue was that the ESP module had "dropouts" in communication with the ECU.