: some code questions



cart69
12-09-04, 01:43 PM
the codes my carhas are as follows

P017 O2 SENSOR FRONT

P030 ISC RPM OUT OF RANGE

P095 NEAR STALL DETECTED

S038 ELC SHORTED

for the 017 should i change both o2 sensors or is just the front ok?

the 030 code the car idles high, idle never gets under 1000 to 1200 rpm should i replace the isc? i even turned in the adjuster screw on the isc and it still went back to the same spot, unplugged the isc and the idle went up drastically.

095 code would one of the other codes lead to this?

s038 code is a ride control device thats on the rear axle correct? thats what i was told, and also that the connector gets crapped up on these sometimes and needs cleaned then my service ride message will go away. any truth to that any other suggestions??

also the codes have been reset and they came back. thanks for any light on the problems guys

BeelzeBob
12-10-04, 01:27 PM
Just change the one O2 sensor if that is the only code that is setting.

Something is wrong with the idle speed control sounds like.....

You should never need to turn the plunger on the idle speed control motor for adjustment. The PCM controls the idle speed by actuating the idle speed control motor. If the idle speed control motor is extending like you mention (high idle when disconnected) then it is probably working OK for the moment. I would suspect something else is holding the throttle open other than the idle speed control motor...something such as a misadjusted cruise control link or something else.

Search using "idle speed control motor" and read my posts. There is a lot of pre-posted info on how to override the idle speed control motor and check it's operation by manually retracting it and checkiing for clearance at full retract. That is the place to start.

If you simply let the engine idle and hold the throttle open slightly (2500 rpm or so)with one hand and depress the plunger of the idle speed control motor with the other the ISC motor should retract and keep retracting until it stops. Yank the wire connector off the ISC motor when it is fully retracted to "freeze" it in the fully retracted position. Let the throttle gently return to idle. The engine should idle down to about 450-500 with the AC off. If not, then something is holding the throttle open other than the ISC motor. Remove the cruise control link and see if that solves the problem. You must find what is cuasing the engine to idle too fast when the throttle is completely clossed to soleve the problem with the idle speed (something like a vacuum leak or throttle body deposits gripping the blade before it closes....) Clean the throttle body bore and see if that corrects the problem. Check for a too tight cruise link or other binding of the throttle cable or interference with the throttle linkage and the floor mat (aftermarket mats are notorious for interfering with the throttle...)

mcowden
12-10-04, 01:34 PM
Hey Cart69 -

I would just replace the front O2 sensor. If the other is bad, you'll get a code for it. They don't always go bad at the same time, and at somewhere between $50 and $130 per sensor, I would prefer to save the bucks and replace them when they go bad.

As for the ISC, some further troubleshooting is probably indicated here. Is there any chance there's an air leak into the intake somewhere? Hear any sucking or whistling sounds that shouldn't be there? If not, then probably the ISC needs a replacement, but I'm sure someone else here will have better advice on this one.

The near stall code may have been there a long time, who knows? It could have something to do with the ISC and O2 sensor codes, but if you haven't noticed a problem, fix the first two problems, clear the codes, and it probably won't come back unless some new problem crops up. Does it run OK other than the idle problem?

The ELC problem I've had to fix before. The exhaust valve on it is a little solenoid that tends to get water in it and rust. The solenoid shorts out and you wind up with that code. It is above the rear axle and not too difficult to access, at least on my '96 SLS. You don't necessarily have to replace the whole pump, dryer, and solenoid at the same time, so if you take it out of there and the solenoid is obviously the problem due to rust, or if it tests bad, replace just the solenoid. Sometimes the solenoid and pump are one unit, in which case you have to replace the pump but not the dryer. The pump is kind of expensive last time I checked, so you might want to consult a salvage yard or used parts source, otherwise you can order them new at www.gmpartsdirect.com. It's also possible the connectors are become crapped up, in which case you should be able to just clean them up and seal the connectors somehow, maybe some silicone grease would help here, and it should be OK.

Let us know what you find out. Somebody here will be able to help if this doesn't point you in the right direction. Good luck...

M C
:cheers:

cart69
12-10-04, 02:21 PM
i do hear a noise that sounds like a vaccuum leak but its over by the power steering pump, and i assume that the noise, i havent yet disconnected the serp belt and run it to see if the noise is still there. as far and throttle crap holding the plate and making the idle go up i will clean the bore but i dont suspect that to be the problem, when i turned the isc adjuster screw in the blade closed, but no matter what the idles when hot is around 1000-1200, every now and then it seems like the throttle or somethin sticks and holds the idle higher, but i have found no evidence of a sticky throttle, weird i hope to tear it apart this weekend and figure it out!!.

also the security light has been on since i got the car any clue why its on??

i know the fix it list never ends!!!

mcowden
12-10-04, 04:01 PM
The throttle blade may not *look* like it would stick, but I'll tell you from experience that what looks like normal deposits around the blade will make it stick under weird circumstances. It doesn't take long to clean it out. I would definitely do that first.

It's also possible that the "near stall detected" combined with high idle indicates some sort of problem with the data that's controlling the ISC. Does it run off the tachometer data or a crank or cam sensor? Just a wild thought. If you haven't detected a near stall, I can't think of a good reason why it would have detected one. Bbob?

Where do you live in Illinois? Anywhere near the west 'burbs of Chitown?

M C
:cheers:

cart69
12-10-04, 04:30 PM
i live in cortland il zip is 60112 about an hour or so from chicago, i was planning to scrub the throttle body as well when i take the intake off this weekend