1994 E320 Code 6 Idle Problem
 

Hello,

I'm having trouble with my 1994 E320. It has the check engine light on and is storing a code 6 (Idle control problem). I have cleared the light 4 times by disconnecting the battery and after about a day of driving the code sets itself again. At least it's consistent!

I checked the OVP and it was the old part number, so I replaced it. I have also replaced the coil connectors and plugs. These had no effect on the problem.

Here are the symptoms:

Before the check engine light sets itself, The idle is around 700 in drive w/o the A/C on and drops to 500 with the A/C on. It idles and runs smoothly.

After the check engine light comes on, the idle drops to about 400 and gets rougher. It's not really enough to keep the power steering going and I need to keep my foot on the gas a little to get it to idle when I first start it.

Please guide me towards the next round of diagnosis or the next obvious parts to test/replace.

Thanks!!

ALLDATA says to test the EA/CC/ISC system or CC/ISC system depending on wether you have ASR or not. This means you need to get the codes that are stored in socket 14 from the DLC. Do you have a code reader?

Dale,

I don't have the code reader, but now that I know more info is available at socket 14, I'll make one and pull the codes.

Thanks for the tip.

The codes retrieved from pin 14 included 2, 5 and 11.

I cleared all of them and it's driving okay again. I'm sure that when the systems go through their diagnostics again, the codes will reset and my idle problem will return. This has been pretty consistent.

Your assistence is appreciated.

Thanks!

I wanted to add some more information since I have spent a LOT of time reading the old posts on similar problems. The idle is low, and a bit rough, but does not "hunt" up and down in rpm as others have experienced. I hope this helps.

Can anyone help me with interpreting the codes 2,5,and 11 from pin 14?

Thanks,

Thanks Zafar, but I think the codes you supplied may be for another car...

From JimF's site I pulled the following data:

2: EA/CC/ISC Control Module
5: Stop Lamp Switch
11: Fuel Safety Shutoff to LH-SFI Control Module

I cleared the codes last night and the only one to return is code 2.

After reading more, I tested the cruise control - it is dead, not working at all.

I also checked for the date on the wiring harness tag. The only tag I could find was on an unused fuse holder mounted near all the ground connections by the battery. Is that part of the main harness or a different one? The tag said 02/94. If that is the tag for the main harness, then mine has not been replaced.

These symptoms are leading me toward replacing the harness and the throttle actuator.

I will cut the harness open near the coils tonight to check the condition of the insulation. What else can I test before beginning to acquire expensive parts?

I hope a tech will weigh in soon...

Thanks again!!

sounds like you might be experiencing the same thing I'm in the middle of. I just ordered a new CC/ISC (throttle body or throttle actuator, whichever you prefer) because the wiring harness going into it was completely shot. I was getting the same codes you just noted, so my suggestion, before you go any further, is to check the wires going into the throttle acuator and see what shape their in. I bet the insulation is cracking!!!

See my original post under tormenting problem with my 95 E320.

I had posted the codes for the HFM Pin 8. Below are the codes you are looking for. Your car does not have the LH-SFI; it is HFM.


Code 2
EA/CC/ISC Module
Safety Contact Switch
Stop Lamp Switch
Cruise Control Switch
Actual Value Potentiometer
Starter Lockout/backup lamp switch
Close Throttle positon switch
Engine Speed Signal
Vehicle Speed signal
Engine Harness

Code 5
Stop Lamp Switch

Code11
Fuel Safety Shutt off signal to Engine Control Module
Closed throttle recognition signal to Engine Control Module

JetForeman, I've read your posts. We will have to keep comparing notes as we go through this. I'll watch out for your update when you get your new Throttle Actuator installed - good luck!

Zafar, thanks for the list! This gives me more things to look into before spending the big bucks.

I cut into the harness and it's shot. I'll replace it and hopefully that will do it.

I jusrt came across this thread . . .
 

so I would have added my 02$ earlier.

Yes the code by zafar are very complete; that's about everything that can go wrong.

Good catch re the harness: probably will fix all problems (CC,etc) after the harness is replaced.

Last week, my ETA (Elec Throttle Acutator) went bad but it wasn't the harness.

"I cut into the harness and it's shot. I'll replace it and hopefully that will do it."

Are you talking about the foot long section of wires attached to the throttle actuator or the main engine wiring harness?

Also read my update under tormenting E320, I finally resolved all running problems!!!!! For Now.

I cut into it at the coil signal input. Man, it was REALLY bad. I'm floored that a car can run at all with wiring like that!

I don't want to disturb the Throttle Actuator wiring unless it's needed. I have a good feeling that the harness will resolve my issues. I'll report back.

JetForeman, I'm glad to hear that your problem is solved! Congrats.

I replaced the engine wiring harness and I am still having problems. I sure don't feel bad about replacing the harness because it was definitely BAD. The car runs better.

With the new harness in place, I got a code 6 from the main code flasher and code 2 again from pin 14. The cruise control still does not work at all. Any suggestions on things I can try or test before purchasing a throttle actuator?

JetForeman, do you have a picture of the bad wiring on your TA that you could post? That would really help me know where to cut into it and check the wiring.

Replacing the wiring harness was a piece of cake. This job should not intimidate anyone. I took lots of pictures and if someone wants to volunteer to help with the web page stuff, I will provide the pictures and writeup for a DYI article. Any takers? Any interest in the DIY article?

Thanks again,

I've got pics of it after I removed it. If you make a cut in the middle of the harness going into the CC/ISC actuator unit you will know, TRUST ME, you will know because the wires will be crumbling the whole length from the socket all the way to the circuit board inside of the actuator.

Also the code 6 from the LED is telling you that your ISC/CC is inop so it's telling you to seek more info from socket 14 of which you did. The code 2 your getting is more than likely from a bad wiring harness. That's one of the things ALLDATA recommends checking with this code.

Thanks Dale. I sent you an e-mail with a few more specific questions.

your e-mail went to my house e-mail, of which I won't get to until later on tonight. But then again your 3 hours behind me so I'm sure you'll get it before the nights over.

Old Harness - note crumbling

Wires exposed at coil input

My throttle Actuator - this is sad. I will be writing a letter to MBZ letting them know how I feel about this!

Definitely not pretty, I hope my directions helped you out some. Looks like you know what direction to go now.

Really scary...

About the label/sticker indicating date of the harness, did you come to a conclusion? Did the new ones had the same?

Reason is mine is looking fine, but there are some strange things going on at certain conditions, so I would like to find out if the PO has replaced it or not.

Regards
L.

The label I mentioned earlier was on a different harness, not the main engine harness.

The tag on the engine harness was behind the battery. It said 02/94.

I didn't even read the tag on the new one, so I don't know the manufacture date.

CONGRATULATIONS
 

CONGRATULATIONS.


The foult code Threadid is very interesting.

I would appreciate to know the codes for 190 E, 2.6L, 1988 and

for 300E, 1988.

Mr. 300EE320 I'm interested in DIY article and pictures.

Mr. ZAFAR, can you help me with the codes?


Thanks.


Mario farias

laprefar@cantv.net

My car is back to normal after replacing the throttle actuator. The idle is now where it should be, the cruise control is working correctly and there are no codes.

So, to sum up what I did, I started with the cheap attempt and replaced the OVP. I then replaced the main wiring harness, which was in very poor shape. Then I replaced the throttle actuator, which was the pretty clear culprit from the beginning.

Ouch, that was expensive...

Re: CONGRATULATIONS
 

Unfortunately, your 190E 2.6 and 300E both have the M103 engine with CIS fuel injection.

1993 300E's really should've been badged as E320's, like 1994 and 1995 E320's. These cars have a 3.2 liter M104 engine with a completely different fuel injection system.

Your cars do not have a code reader, and do not store codes.

Also, your cars do not have a throttle actuator. Instead, your cars have an idle control valve.

The good thing, though, is that your cars do not suffer from degrading wiring insulation like 1993-1995 300E (3.2) / E320's.

Glad to hear your car is back to normal, it's a huge expense but now that it's over your wiring problems should never reoccur. I sure hope mine never do!!!

MR. SUGINAME
 

Thanks Mr. Suginame. I fell better after your reply, however

I would appreciate to anybody tell me for what is the test

socket located on the car left fender.


Thanks.

Mario farias
laprefar@cantv.net

Mario,

You will probably have better luck if you start a new thread with your question. Most of the folks following this one are probably 1994 E320 owners.