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.