1991 INTL REST light gone crazy

[billschroeder5842]

My INFL REST light comes on and off intermittently with no apparent reason on my 91.

There seems to be no rhyme or reason. I can start the car, watch the flashes go off drive it and it sometimes comes on. A few more miles, and it may go off or stay on-- you pick. Most of the time I don't see it and everything is normal, but every now and then It pops out of no where.

Also, the car seems to reset itself when I turn it off and/or go through a new start cycle again.

Now, I've read about the 90s having issues and the fix was made for 91. I read that due to the location of the sensors, they are prone to corrosion and the fix is to pull them off, clean the surfaces and reinstall.

I've also read that the code need to be cleared, but the light goes off. Does the system store the code or does it disappear?

Any ideas?

[jss06c6]

Bill,

Check out Mike's post. (MickeyD). Good write up there. He's dealing with the same issue on his '90..

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[MickeyD]

Boy am I. Don came up and he tried to help clear it with paper clip and then we went to his house and tried Cliffs code clearer. Didn't help. Infl rest an seat belt light still on. Thanks to Don (32valvesftw), what great help today. Did bring his ramps to help with oil change. Thanks again.

[jss06c6]

Mike,

Feel free to come over here and put it up on my lift for next oil change!

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[jss06c6]

Mike,

Let's see if we can clear it up. How's your schedule next week?

We can put it in my shop and get after it.

Steve

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[WVZR-1]

OP - Diagnostics, codes and procedures for a '91 are way different than anything you see mentioned for a '90 MY. Disregard everything and do diagnostics in the FSM. A FLASH diagnostics will only do current codes I believe BUT if there are HISTORY codes it will I believe flash a 13 and then the HISTORY needs read using a scanner.

Doing the sensor maintenance is time wasted without doing the diagnostics first for '91 or later (MY THOUGHTS). Since your SIR is intermittent it "hints" that when there is NO SIR there's only a stored history likely. If checked when "LIGHT ON" you could likely assume that if one FLASHED is likely the same in the history. A read of the FSM 9J before doing a thing. A poor connection maybe at the connectors at the column base, the air bag itself, the DERM or to the sensors. A '91 also has an ARMING sensor.

[billschroeder5842]

Originally Posted by WVZR-1

OP - Diagnostics, codes and procedures for a '91 are way different than anything you see mentioned for a '90 MY. .....A poor connection maybe at the connectors at the column base, the air bag itself, the DERM or to the sensors. A '91 also has an ARMING sensor.

I drove her yesterday with about 5 on/off sequences-- nothing-- all ops normal.

One thought I had is that I've been doing a lot of cleaning under the hood and engine (Oil line replace) as of late. Simple green, hose rinsing, brake cleaner..etc. The under hood is looking better, but some of the water may have worked its way to a sensor causing a short?

I'm thinking of taking the panels off and getting after the sensors (cleaning and re-grounding) as a preventative maintenance, but other items keep taking precedence as long as the light is out!

BTW... is there a "preferred" code reader/clear or is the paper clip method the way to go? I had an 82 with the ALDL and I bought a connector to my laptop. Very cool program.

[32valvesftw]

Mike, the more I think about your situation, its the sensor on the passenger side. What we were seeing when the light momentarily went out was the system recognizing that the process was done, and the resetting due to the fault. The next step should be cleaning the connections and checking the wiring, then see if there is a code. I'm happy to help f you need.

[jss06c6]

Originally Posted by billschroeder5842

I drove her yesterday with about 5 on/off sequences-- nothing-- all ops normal.

One thought I had is that I've been doing a lot of cleaning under the hood and engine (Oil line replace) as of late. Simple green, hose rinsing, brake cleaner..etc. The under hood is looking better, but some of the water may have worked its way to a sensor causing a short?

I'm thinking of taking the panels off and getting after the sensors (cleaning and re-grounding) as a preventative maintenance, but other items keep taking precedence as long as the light is out!

BTW... is there a "preferred" code reader/clear or is the paper clip method the way to go? I had an 82 with the ALDL and I bought a connector to my laptop. Very cool program.

Bill,

Check the ALDL connector you have for the '84, I suspect it is early style. You can pick up a cheap OBD1 code scanner at most auto parts stores. It will give you the codes, but not clear the codes.

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[WVZR-1]

Originally Posted by billschroeder5842

I'm thinking of taking the panels off and getting after the sensors (cleaning and re-grounding) as a preventative maintenance, but other items keep taking precedence as long as the light is out!

This I believe would be "time wasted" without doing diagnostics 1st.

Scanning and diagnostic requirements are very different dependent upon the system that you want to check. The "jumper" FLASH or the ECM/CCM through the DIC are very reliable for some. Short of a quality Tech1/1a or the Snap-on offering everything else is insufficient. A laptop for "run diagnostics" yes but NOT for "controlled devices" in the car.