Engine light ON. Should stop driving it? (1 Viewer)

Joined
Jan 26, 2005
Messages
160
Location
Eagle, Idaho
 
I have a 1994 LC with about 144K miles, it had a tuneup about 4K miles ago and the O2 sensor was replaced by the PO last year.
It has been driving fine and all the sudden the engine light went on this afternoon. The truck drives fine and can't feel any differences or problems on the driving or performance.
Can I continue driving it until I can figure out what the problem is and another question is that since there is no OBDII or check port on this year what is the procedure for finding out what is wrong?
I am sure this has been covered in another thread so if anyone can point me in the right direction it would be great.

Thanks,

Antonio
 
Joined
Jun 18, 2004
Messages
1,485
Location
Pacific Northwest
 
 
 
It is easy to figure out the error code. I did a quick search and here is what you need to do. It is really easy. If you do not yet have an fsm post the code up here.


There is a DataLink Connector against the firewall in the engine compartment on the passengers side. Use a paper clip to short T1 and TE1 with the car off. Then turn the key to the ON position. The CEL light will flash, pause, then flash some more, followed by a long pause. Just count the flashes. The first set of flashes is the first number in the code followed by a short pause. The second set is the second number followed by a LONG pause. THAT'S THE CODE.
The process will then continue and you'll either get the same code, or a different one. Small pauses separate digits in a code, LONG PAUSES separate multiple code numbers.
 

e9999

You want to do what...?
Moderator
Joined
Sep 21, 2003
Messages
17,130
Location
US
 
 
 
I would not drive with the light on till I figured out the problem...
 

Gumby

Supamod
s-Moderator
Joined
Dec 13, 2002
Messages
12,259
Location
Knee deep in hookers and gin
 
 
 
 
CHeck it out, but I wouldn't stop driving it. If the oil light or temp light comes on, that's different. The yellow CEL light is often no big deal. I'm trying to think of a reason it would come on, be an issue that could cause damage and not run bad. You might run a bit rich, but other than that...
 

powderpig

SILVER Star
Joined
Jul 12, 2005
Messages
1,026
Location
Boulder Foothills, CO
 
 
 
I would first get the code and post it up to find out what is up. Usually all is fine as gumby states. But it is always better to find out what is up, then to drive around in fear of something really wrong. I may be a good time also to order a FSM to have all the info you may need if you chose to keep your crusier. later robbie
 
Joined
Sep 6, 2003
Messages
3,185
Location
Tulsa, OK
 
my lx with 170,000 miles had the CEL come on not to long ago - fuel system recirculation pressure low or some such. Basically, I need a new gas cap.
 
Joined
Jan 26, 2005
Messages
160
Location
Eagle, Idaho
 
SR.GRINGO said:
Use a paper clip to short T1 and TE1 with the car off. Then turn the key to the ON position. The CEL light will flash, pause, then flash some more, followed by a long pause. Just count the flashes.
Thanks for the info, I did what you recommended and the code I get is code 71.
What does this mean?
Do I need to replace something?

Thanks,

Antonio
 

NorCalDoug

problems solved daily...
Joined
Oct 27, 2003
Messages
6,217
Location
uhhhh...duh...Northern CA
 
 
 
e9999 said:
I would not drive with the light on till I figured out the problem...
In my '94, I drove with the CEL on for several thousand miles. :D
Turned out to be my O2 sensor. If I followed your logic...I would've been stuck out in BFE for a long time.
 
Joined
Nov 13, 2002
Messages
539
Location
The Saratoga slums, CA
 
 
 
 
atijerino said:
Thanks for the info, I did what you recommended and the code I get is code 71.
What does this mean?
Do I need to replace something?

Thanks,

Antonio

A code 71 = EGR system. Clear the code and wait for it to happen again. In the mean time, start reading the 80 series faq on EGR codes:
https://forum.ih8mud.com/showthread.php?t=12498
I just recently threw an EGR code in my '97. Turned out to be a cracked vacuum hose feeding the modulator. Luckily, a quick easy fix.
 

e9999

You want to do what...?
Moderator
Joined
Sep 21, 2003
Messages
17,130
Location
US
 
 
 
NorCalDoug said:
In my '94, I drove with the CEL on for several thousand miles. :D
Turned out to be my O2 sensor. If I followed your logic...I would've been stuck out in BFE for a long time.
well, try driving several thousand miles without engine oil or some such similar serious engine issue....
(and yes, I know there should be another light for the oil....)
I can't imagine that the CEL is only for mild emission issues...
Besides I said "until you have figured out the problem" so if the problem is the O2 sensor, then it's probably fine to drive it, but that's a rational decision not a WAG that all is fine...
 

woody

Staff member
Admin
Joined
Jan 15, 2002
Messages
10,302
Location
Toquerville UT
 
 
 
 
I've got a couple thousand miles on mine, light on....same code...and I'll be towing ~1000 miles this weekend...reminds me, gotta get some black tape for that light....

replaced the modulator, cleaned the temp sensor, and have a VSV sitting on the counter for a day I have time to work on it....

generally, the CEL means a sensor stopped functioning or is out of it's expected operating range. Ridiculously rare that it would be a "major" issue....as noted, an oil light is worth investigating sooner than later...
 

NorCalDoug

problems solved daily...
Joined
Oct 27, 2003
Messages
6,217
Location
uhhhh...duh...Northern CA
 
 
 
e9999 said:
well, try driving several thousand miles without engine oil or some such similar serious engine issue....
(and yes, I know there should be another light for the oil....)
There IS another light for engine oil. Usually best to not ignore that one.

e9999 said:
I can't imagine that the CEL is only for mild emission issues...
Besides I said "until you have figured out the problem" so if the problem is the O2 sensor, then it's probably fine to drive it, but that's a rational decision not a WAG that all is fine...
The CEL will come on for emissions. It'll come on for any number of things. If it's on and there's no discernable problem with your vehicle, IMO, there's no need to panic.

Do, by all means, find out what the problem is and get it taken care of...
 
Joined
Sep 6, 2003
Messages
3,185
Location
Tulsa, OK
 
I had a friend at work read my code and reset it - interesting thing is it read as GM code? Anyway - he said that what he read with his software was that 99% of ECLs were just senor errors or other garbage. It's that 1% that'll get ya'.
 
Joined
Sep 19, 2005
Messages
83
Location
Nor Cal
I'm gonna go read the FAQ that was suggested, but in the meantime, how do you clear the code with a paperclip?
 
Joined
Jan 26, 2005
Messages
160
Location
Eagle, Idaho
 
I followed your advise and went ahead a reset the code at around noon. This afternoon on the way home the CEL came on again, I went home and while still hot took the modulator out and all the vacuum hoses associated with it and with the EGR valve, I removed the modulator filter and it was pretty dusty, but not a lot of heavy carbon build up, them I cleaned the filter with (soaked it) Seafoam and there was a lot of carbon at the bottom and some (water? or oil?) droplets that floated on the seafoam liquid. I blew on the hoses and cleaned and dried the modulator pretty good. Put everything back together, reset the CEL and drove a few miles, I noticed a little lower idle speed and it still looks ok. I will see what happens tomorrow on my commute.

Thanks for the help, tips and advise.
 

NorCalDoug

problems solved daily...
Joined
Oct 27, 2003
Messages
6,217
Location
uhhhh...duh...Northern CA
 
 
 
:D

actually, earlier (non-ODB-II) compliant 80s use a paperclip to pull the codes.
later (95-97) 80s require a ODB-II code reader to obtain the MIL code.

Clearing can be done a number of ways -- via code reader (if it has that feature) or by disconnecting the battery for aprox 30 seconds.

You can also pull something else...but I can never remember what it is. I'd just disconnect the battery.

Whatever cause the problem will likely cause the light to come back on...
 
Joined
Jan 26, 2005
Messages
160
Location
Eagle, Idaho
 
The other way to reset the code is by removing the EFI fuse that is located on the fuse in the engine bay by the driver's side.
 
Joined
Jan 26, 2005
Messages
160
Location
Eagle, Idaho
 
EGR CODE 71 problem solved.

Posting this as a follow-on to my earlier post.
I ran the diagnostics as per the FSM and the test for the EGR Vacuum regulator did not pass the High Vacuum test. According to the FSM this is an indicator that the EGR Vacuum regulator was defective.
I ordered the replacement part from CDAN and replaced it on Monday. I got the blue top replacement instead of the original green top unit.
This solved my Code 71 problem.
I don't know if there is a relationship, but my smog test was due this week and had it done on Tuesday and passed with flying colors with number well below the required to pass.

Thanks,
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top Bottom