Check Engine Light Update - PeachParts Mercedes-Benz Forum

rainmaker · #1 08-07-2001, 06:06 AM

I took the car to the shop over the weekend to (1) have the lower control arm bushings installed and (2) diagnose check engine light. I also complained of a slightly low idle speed (around 490-495 rpm when warm/hot).

Got the car back earlier this morning.

The lower control arm bushings weren't installed as only 1 bushing arrived (an apparent miscommunication between Service and Parts). Hmmm... Have to wait another week (or two) for the parts to arrive.

They checked the car over with the HHT. The Check Engine light was reset as well. The tech wasn't able to give me the fault codes that cropped up but 'translated' it for me. (Although I insisted on getting the fault codes, but I guess he thought he knew better. Hmmm...) Anyway, here's what he wrote down:

Problems:
- Idle speed control
- Intake air temp sensor

A further notation read:
"Control Module EFP N4/1"

Can anybody translate this into English? Jim, are you there? You seem to be the expert here.

Problem with not getting the original fault codes is that I can't reference what he wrote down with know fault code interpretations and fixes. I wanted to learn more about this car...a critical part of ownership I always believed...

The good news is the Check Engine light hasn't come on yet although I have driven the car extensively today.

Many thanks...

JimF · #2 08-07-2001, 11:23 AM

Here's how I translate those 'terse' notes:

Problems:
- Idle speed control <--- Menu #2; DTC #6
- Intake air temp sensor <--- Menu #2; DTC #9

A further notation read:
"Control Module EFP N4/1" <--- read Menu #8 for details on the Electronic Accelerator Module

Hope this helps.

rainmaker · #3 08-07-2001, 11:53 AM

Thanks for the reply.

You were pertaining to your website, right?

If so...did you mean menu #5 (DM DTCs)? There were no DTCs under your menu #2 (Diagnostic Connectors, Controller Area Network and Scan Tools).

The DTCs (#6 and #9) on Menu #5 matched the problems the tech mentioned.

And now the $64K question...what next? Seems to me the car needs to sit at the dealers for a while for a slew of more tests?

Michael · #4 08-07-2001, 12:36 PM

For starters I'd replace the intake air temp sensor...it's the sensor that is mounted in the driver side intake air tract, behind the headlight. It's about $20 if memory serves, and you can change it yourself in maybe 15 minutes or less.

I've never experienced the other probs, so I can be of no assistance with those. Sorry

Good luck!!

rainmaker · #5 08-07-2001, 01:07 PM

Or at least Bill should give him his own R&R forum

Michael, thanks! You have probably answered 90% of my posts and provided me with a good chunk of the solutions!

JimF should get Diagnostics Guru status and moderator of the Engine Diagnostics forum which Bill should provide Jim with as well!

Many thanks everyone for lending a helping hand and the occasional useless (but funny!) posts...

Michael · #6 08-07-2001, 03:28 PM

Glad to help, amigo-I know I've gotten a bunch of assistance here too, which is what makes this site great

JimF · #7 08-08-2001, 01:33 AM

Rainmaker,

you need a scanner if you're going to get deeper into the codes business!

The only codes that you can read are the ones that "appear" in the Diag Module (DM) and can be read with the LED/sw combo. That's a good start but if it point's to the EA modue (N4/1), then with a good scanner, you can read any/all modules individually to see what's going on. Obviously, that somewhat expensive but will pay for itself as you use it. The PALM Scanner appears to be reasonably priced ($495) and contains all pieces (mushroom, etc.) to read and clear codes in MB LANGUAGE, not OBDII.

Re your codes (corrected):
- Idle speed control <--- Menu #5 for DM; DTC #6
- Intake air temp sensor <--- Menu #5 for DM; DTC #9

A further notation read:
"Control Module EFP N4/1" <--- read Menu #8 for details on the Electronic Accelerator Module

Yes those are for my page (as you have already figured out) and I gave you the wrong menu number.

Michael's given you good advice: priced one the other day for $17.80. But check to see that the connector is plugged in. Yes, it happened to me last month. Forgot to hook it up after removing the intake tubes. So check it out.

Re Idle Speed: As I understand it, the idle speed is controlled by the N4/1 module but it's also controlled below 500rpm by the DI module (see Menu #4).

Also there's a linkage adjustment that allows you to adjust the idle by tightening/loosening a nut. I've tried it on my car (just for the exercise) and it can not LOWER the idle, but it certainly can raise it!

rainmaker · #8 08-08-2001, 03:00 AM

Quote:

Originally posted by JimF

Also there's a linkage adjustment that allows you to adjust the idle by tightening/loosening a nut. I've tried it on my car (just for the exercise) and it can not LOWER the idle, but it certainly can raise it!

Aha! That's what I was hoping to hear (or read)!!!

Is this by any chance the horizontal bar with a nut somewhere near the windshield?

On the scanner...still trying to figure out if I'm really up to it. I'm afraid I'm going to go berzerk with it and go on replacing every part it points to!

thanks Jim!

JimF · #9 08-08-2001, 11:40 AM

I believe that the throttle linkage is adjusted by the nut [28], located on the back of the manifold underneath the air cleaner.

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