Service Engine Soon

Are there any trouble-codes? This guide can help

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Please run down this guide and report back.

I dont know about the trouble codes, My local auto zone said they could only check the codes if I had OBD II, Which I dont have, But I do have a Data Link Terminal, Is this OBD I ? & is it worth me buying a OBD I tester, they are pretty cheap, I guess they blink the #s of the trouble code, I have a Haynes manusl that lists the codes, Just not sure if this is an OBD I terminal, Its just listed in the user manual as a data link terminal.
Thanks for the reply
Jim

The 94 and 95 years are crossover years between OBD1 and OBD11. You may have a hybrid system.

How many pins in the data link connector? If there are 12 pins, that should be obd1.

If there are 16 pins, you may have what they call OBD1.5, it's a hybrid system, uses 16 pins but you have to use an OBD1 code reader.

I don't have much info on that hybrid system. I'd hate to see you buy an OBD1 code reader and then it not work on your system. Maybe the store would let you bring it back, if doesn't work? You can ask.

My first thought about your CEL was to check the 02 sensor and circuit. I can't tell you to replace it without doing some tests.

Thanks for your help, Its the 16 pin OBD 1.5, Auto Zone wont read it, I might try a dealer or a friend who has a code reader, The service engine light hasent gone on the past day or so, But today, After driving 65+, then slowing to 40- mph it went back on, Also the car idles a bit rough, Im changing the fuel filter as the car has been run to almost empty a couple times, Also changing the PCV valve, hopefully I can get the error codes, it still runs good, never stalls,but it must be something ! Possibly O2 sensor like you said.
Thanks Again for your help & I will make a donation asap, this weeks a little tight though.

I finally got The Error Code, Just one came up, EGR Valve ! actually EGR selonoid #2.
Thanks Again
Jim

I have the same OBD-1.5 system in my '95 Trans Am. How'd you pull the codes? The more specific the better because I'd rather do it myself even if I spend a little $$ on equipment rather than pay the dealer $50 bucks to do it.

Feel free to e-mail me a reply as well since I only found this forum through a google search a few minutes ago! (mikegdiaz @ gmail.com)

I have a 1995 Camaro which is an OBD 1.5. I Can't seem to find a code reader that will work with my car. I would rather buy a code reader than take it to a shop.so my question is where can i find a code reader that will work with my car.

Jumper A to B on the ALCL and count the flashes example DTC 12 Flash pause then flash flash it will show two more times before it goes to the next code if any

Chevrolet
13 Open Oxygen Sensor Circuit
14 Coolant Temperature Sensor (High Temp Indicated)
15 Coolant Temperature Sensor (Low Temp Indicated)
21 Throttle Position Sensor (Signal Voltage High)
22 Throttle Position Sensor (Signal Voltage Low)
23 Manifold Air Temperature (MAT) Low Temp Indicated
24 Vehicle Speed Sensor (VSS) Circuit
25 Manifold Air Temperature (MAT) High Temp Indicated
32 Exhaust Gas Recirculation (EGR) Circuit
33 Manifold Absolute Pressure Sensor Circuit (High Sig.)
34 Manifold Absolute Pressure Sensor Circuit (Low Sig.)
35 Idle Air Control (IAC)
41 Cylinder Select Error
42 Ignition Control (IC) Circuit
43 Knock Sensor (KS) Circuit
44 Oxygen Sensor Circuit (Lean Exhaust Indicated)
45 Oxygen Sensor Circuit (Rich Exhaust Indicated)
51 EEPROM or ECM Failure
53 System Voltage Overcharge
54 Fuel Pump Circuit (Low Voltage)
55 ECM Error
61 Degraded Oxygen Sensor
62 Transaxle Gear Switch Signal Circuit
63 A/C Refrigerant Pressure Sensor Circuit

Computer problem
1991 Chevy Camaro V8 Two Wheel Drive Automatic 10000+ miles

i just got done looking at a 91 camaro rs 305 and thinking about buying it but 1 small problem the check engine soon light was on but it is a carb motor could this just b and o2 sensor or sumthin more? and if so cant i just eliminate the o2 sensor and b just fine

yes could be 02 sensor why eliminate them won,t matter

No, you engine is not carbureted. It's fuel injected. Here is a way to get the codes. These codes are for an 89 but should be the same for 91.

has someone converted it to carb?

No, I'll bet he's mistaking a TBI for a carb. People do it all the time.

ya your prob right lol

service engine light come on when you have been doing 60 / 70 mph on the freeway, and get out of it around 40 mph the serive light come on and stays on till you turn the engine out. Give it about 10 mintines and then start it, it's ok. Change oil, oil filer, air filer,and spark pluge. service lights still comes on.

thats typical of egr problem. check for codes and get back to us. under drivers side dash is the aldl connector. use a small piece of wire and jump terminals a@b then turn on key and watch for flashes of the check engine light. write down the number of flashes then get back to us.

I have the exact same issue. I thought it was a possible cruise control issue. I jumpered pin A@B but got no codes at all. The check engine light did not flash anything. After about 10 min the light went out when I restarted it.But now I will focus my trouble shooting to the EGR system.

How do you reset the sevice engine light.

You must first, fix the problem that triggered the light. Then the hook a scanner up to the OBD plug and follow the instructions to reset the light. Autozone or a place like that will do this for free.

However, since this is an OBD 1 vehicle you will have to follow this guide to help pull codes and then erase them. Unfortunately resetting a checking engine light is not going to fix anything so we need to fix the issue first and then we can just clear the codes.

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Please run through this and let us know if you have other questions.

1992 Chevy Camaro V8 Two Wheel Drive Automatic
----------------------------------------------------------------
I bought a 92 camaro that hadnt been started in 6 years. It took some work but i got it running. It had no power and the exaust smelled like rotton eggs. I replaced the cat converter with a direct fit replacement. The car started and then started surging from 1000rpm to 100rpm over and over for a few seconds then died. If i keep trying to get it to start it diles real rough for a second then dies and sounds like its spitting back through the throttle body. I have replaced the ECM,EGR,TPS,MAP,Idle controll valve,Oxygen sensor,and the Air intake temp sensor. My code reader doesnt show any codes stored. The car idled fine when i drove it into the shop and replaced the cat, What could the problem be? Someone please help me!!!

Start by checking the fuel pressure-if its okay-check the ignition timing should be 0/TDC follow procedures below and also recheck the IACV and TPS Also check the EGR and PCV valves

Here's how to clean the IAC valve: Disconnect the air intake ductwork from the throttle body. Start the engine, then increase and hold the idle speed to 1,000 to 1,500 rpm. Spray the throttle cleaner or engine cleaner into the throat of the throttle body, aiming for the idle air bypass port (usually located on the side or top of the throttle body opening). Give this area a good dose of cleaner (about 10 second's worth). Turn the engine off to allow the cleaner to soak into the IAC passageway. Wait about three minutes. Restart the engine, rev and hold at 1,000 to 1,500 rpm, and repeat the cleaning process again. Turn the engine off again, and reattach the air intake ductwork to the throttle body. Start the engine and rev and hold to 1,500 to 2,000 rpm until no white smoke is coming out of the exhaust pipe

Electrical problem
1988 Chevy Camaro V8 Two Wheel Drive Automatic

I've had my 1988 Camaro IROC garaged for several months. I had to remove some wiring from inside the door in order to remove the door to install new hinges.

I pulled the car out several months later and none of the dash gauges work. The RPM, Fuel, Oil Pressure and battery gauge wasn't working. Also, the Service Engine Light doesn't work. All of this not working suddenly has to have the same cause. Any suggestions would be greatly appreciated. Everyone is wanting 75 to a 100 dollars an hour to check it with no guarantee---especially on the amount of time to fix it.

Start by checking all the fuses. Pull them out one at a time and test with multimeter (ohms) or fuse tester.

The wiring in the door may be pinched causing a short.

I've checked the wiring in the door and it's fine. All the fuses are good as well. The one major difference, where I can't seem to find the common denominator is that whatever it is that is causing the gauges not to work and the Service Engine light to work is that all of these only come on when the ignition switch is in the run position. I don't think it's the ignition switch itself because the car shoudln't run if it was. Any suggestions?

The SES light should come on with ign. on (not started) and go off when engine starts.

Is is logical to assume that if it was working before the door repair and not working after, there is a problem with the wiring in the door.

I would remove the inner door panel and re-check the wiring, and insulation.

Also consider the possibility that they are not related.

Also consider that when dealing with a car that is 21 years old, it can be very easy to inadvertantly break a wire or route it incorrectly.

Hello,

My 1987 Camaro IROC has been off the road for 8 years but recently returned it to service - engine is lacking power and running rough (smooth at idle). A check with a scan tool indicates no trouble codes but at idle shows an OPEN circuit at times and CLOSED at times (even after warming), and both LEAN and RICH Steady (doesn't switch back and forth like it is supposed to).

After 75 miles of test driving the performance is still the same - sluggish, no power and almost stalls when you let your foot off the gas - had the scan tool connected and the engine goes into the OPEN loop and both RICH and LEAN, and then CLOSED loop both RICH and LEAN at speed (varies with throttle).

It is also noteworthy that the fuell filter has been replaced, fuel injector cleaner added (Chev. Techtron) and the air intake checked for obstruction. Also, I montored the oxygen sensor values and they change with throttle and there are no "dead" values for things such as the coolant sensor, etc. Four of the eight plugs were changed (didn't look bad) and the rotor cap and rotor corrosion was cleaned off and connections checked).

Can it be that I have a bad computer or would it more likely be an oxygen sensor issue?

Thanks in advance! I really appreciate any help.

Tom (CT)

That's a lot of miles in it if it haven't been changed or don't recall replace the O2 sensor

I replaced the O2 sensor (believe it was the original, over 23 years old) and the scan tool is still indicating that the car is in the OPEN loop/LEAN. It will not go into CLOSED.

Coolant Temp. sensor appears to be working fine (reading properly), and also the MAF, MAT, EGR etc all appear normal.

The O2 volts is 0.39 to about 0.43 when you rev it. The way I understand it is if it goes above 0.450 volts the RICH light should come on.

Any ideas? Should I replace the computer?

I'm in the same condition with my 87 iroc have you found the answer.

Electrical problem
1989 Chevy Camaro V8 Manual
----------------------------------------------------------------
I have 89 camaro whats the next step if the service light dont worrk and checked the bulb it works?

Usually turns out to be a bad fuse, or connection...

I'm trying to get my son's car smogged and the diagnostic will not send any signal to a scanner. We have replaced the computer and had a friend check it with his scanner and it still won't read. Do you think it is the PROM or poss something else. The check eng light flashes very fast and the car's idle is too high and using too much fuel. ( you can smell it)

My son bought the car last year and knows nothing about working on vehicles. I know a little, but not about vehicles with computers. The veh has been sitting in my driveway for the last 6 months because it won't smog and the tags are expired. Please help get this car out of my driveway.

Too fast an idle speed. If an engine without computerized idle speed control is idling too fast and refuses to come down to a normal idle speed despite your best efforts to back off the carburetor idle speed screw or air bypass adjustment screw (fuel injection), air is getting past the throttle somewhere. Common leak paths include the carburetor and throttle body gaskets, carburetor insulator spacers, intake manifold gaskets, and of course, any of the engine's vacuum fittings, hoses and accessories. It is even possible that leaky O-rings around the fuel injectors are allowing air to leak past the seals. Another overlooked item can be a worn throttle shaft and a defective idle speed speed control motor/valve stuck in the extended (high idle speed) position/throttle position sensor. Also the throttle plate could be binding in its bore and kinked accelerator cable, coolant temperature sensor might not be operating properly misleading the computer that the engine is still cold and computer throwing fuel at it raising the idle speed.

I appreciate your answer about the idle, but it did not answer the orginal question of the computer not sending any thing to a scanner. We have replaced the computer but not the prom. I don't know if the prom was working before my son bought it. the check eng light has been blinking since he bought it. The first time he tried to get it smogged the scanner at the smog place could not read anything.

Your engine management system is OBD1 -try jumping A to B at the ADLC. Should read code 12 -if normal-The scanner might not be compatible.

Could also be an open circuit between the diagnostic connector and ECM.

It has been checked at 3 different shops and also with my friends scanner. None of the places could get any reading from the ECM. I'm going to check if there is power to the ECM. We checked the fuse and it is good. Will a bad PROM cause a scanner not to get a reading?

Check for power and good ground to it-that don't work-change the PROM or replace the ECM.

My 94 camaro's oil pressure at idel is about 20psi but after running for 10 minuts it drops to about 5psi and the service engine light comes on. The engine does not knock or ping and idels smooth. Could it be the oil regulator valve? If so, where is it?

[quote:e0235936c7="Jazzgirl23"]Computer problem
1988 Chevy Camaro V8 Two Wheel Drive Automatic 64000 miles
----------------------------------------------------------------
I'm trying to get my son's car smogged and the diagnostic will not send any signal to a scanner. We have replaced the computer and had a friend check it with his scanner and it still won't read. Do you think it is the PROM or poss something else. The check eng light flashes very fast and the car's idle is too high and using too much fuel. ( you can smell it)

My son bought the car last year and knows nothing about working on vehicles. I know a little, but not about vehicles with computers. The veh has been sitting in my driveway for the last 6 months because it won't smog and the tags are expired. Please help get this car out of my driveway.[/quote:e0235936c7]