Fault Codes 13 and 34... Help?
01-24-2007, 05:35 PM
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Fault Codes 13 and 34... Help?
Hi guys,
I hooked up a code reader and it gave me these fault codes: 13 and 34
According to the book it came with:
---------------------------
13: "OXYGEN SENSOR SIGNAL FAULT - SIGNAL TOO LOW / OPEN LEFT OXYGEN SENSOR CIRCUIT (DUAL SENSOR MODELS)
---------------------------
----------
---------------------------
34: "MASS AIR FLOW (MAF) SENSOR - SIGNAL VOLTAGE OR FREQUENCY IS LOW DURING ENGINE CRUISE"
"MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR - SIGNAL VOLTAGE IS LOW DURING IGNITION ON
"PRESSURE SENSOR CIRCUIT - SIGNAL VOLTAGE TOO HIGH OR LOW (CARBURETOR ENGINES)
---------------------------
I have a stock 1989 V6. I believe the engine is the LB8. 4 spd Auto.
Can anyone please help me? Or atleast point me towards something I can research. I TRIED the search, but apparently "fault", "code", and "13" and seem to be found in every article... So that wasn't any helpful. Oh yea, my cruise control doesn't work either. The SES light is not on when the engine is running, but it is on when the key is in the ignition.
Thanks
I hooked up a code reader and it gave me these fault codes: 13 and 34
According to the book it came with:
---------------------------
13: "OXYGEN SENSOR SIGNAL FAULT - SIGNAL TOO LOW / OPEN LEFT OXYGEN SENSOR CIRCUIT (DUAL SENSOR MODELS)
---------------------------
----------
---------------------------
34: "MASS AIR FLOW (MAF) SENSOR - SIGNAL VOLTAGE OR FREQUENCY IS LOW DURING ENGINE CRUISE"
"MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR - SIGNAL VOLTAGE IS LOW DURING IGNITION ON
"PRESSURE SENSOR CIRCUIT - SIGNAL VOLTAGE TOO HIGH OR LOW (CARBURETOR ENGINES)
---------------------------
I have a stock 1989 V6. I believe the engine is the LB8. 4 spd Auto.
Can anyone please help me? Or atleast point me towards something I can research. I TRIED the search, but apparently "fault", "code", and "13" and seem to be found in every article... So that wasn't any helpful. Oh yea, my cruise control doesn't work either. The SES light is not on when the engine is running, but it is on when the key is in the ignition.
Thanks
Last edited by syko; 01-24-2007 at 05:49 PM.
01-24-2007, 07:53 PM
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I'd start by looking for a leak in the air intake between the MAF sensor and the engine, and check for a vacuum leak anywhere. But the SES light should be on while the engine is running I'd think.
01-26-2007, 08:51 PM
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Car: 1989 Firebird
Engine: 2.8L V6 MPFI
Transmission: Beat to heck 700R4
Code 13 indicates O2 sensor low or missing. That means either your Oxygen sensor is faulty, or not plugged in, or that the exhaust is not heating up enough for the sensor to put out a good signal. An O2 sensor must reach about 350C to put out a good signal. This happens within about 5 minutes of idling.
Here is some decent background info on O2 sensors in general: My own rule of thumb is to just replace it if I suspect anything is wrong. An O2 sensor is a wear item, like brake pads. They go bad after a few years, get tired out, etc. YOu should check to make sure the wire isn't broken.
You have an 89 2.8L. There is a very good chance you have a MAF car, (Mass Air Flow), vs. a MAP car (Speed density/ AKA Manifold Air Pressure). 1989 was the last year for the MAF's, in 1990, GM began putting Speed density in all the cars.
So you only need to pay attention to:
"MASS AIR FLOW (MAF) SENSOR - SIGNAL VOLTAGE OR FREQUENCY IS LOW DURING ENGINE CRUISE"
However, "During Engine cruise" bit is a wee mite wrong. Code 34 indicates "Signal voltage or frequency low" at ANY point, even without being at engine cruise. I can make a code 34 appear by unplugging my MAF's power/signal connector. MAF is basically a sensor that tells the engine computer how much air is flowing past it. The engine computer (ECM) uses that info to calculate how much fuel to supply to the engine. It does so by varying the length of time (usually in milliseconds) that the fuel injectors fire. More air means more fuel is needed.
Now think about the readings from the O2 sensor (which measures how much free oxygen is in the exhaust). That free oxygen amount indicates how completely fuel is being burned. In a perfect motor supplied with an exactly stoichiometric (big word for perfect ratio of fuel to air so that the fuel and the oxygen are both completely burned) mixture there is a certain amount of free oxygen. Too little free oxygen indicates a lean mixture (not enough fuel) Too much free oxygen indicates a rich mixture (too much fuel).
Combine the readings from the MAF which adjust fuel mixture and the readings from the O2 sensor which indicate how stoichiometric the mixture was, and you have the basics of how an engine computer works.
One thing to remember is that the engine computer stores codes as long as the battery is plugged in. If your car was started with either or both of these devices unplugged, than the code could have been set eons ago, and now they could both be plugged in and working fine, but you'll still have a code.
Start with a cold engine. Unplug your negative battery terminal for 5 minutes to clear the codes. Plug it back in and go for a drive. It'll probably drive like crap for 3-5 miles. Just go with it, the engine learns how you drive and what fuel mixtures are right during that first part. Then see if your codes come back. I hate chasing gremlins that aren't really there!
If they do both come back, the next step is to see if they are actually plugged in! Your O2 sensor is on the exhaust pipe, rather near the starter, its a cylindrical looking thing screwed into a hole in the pipe with one wire coming off about 6-12 inches long that goes into a connector somewhere up into the motor. Just follow the wire and make sure its plugged in.
Your MAF is on the air intake. Its a black plastic cylinder about 6 inches long and 2.25 inches in diameter. Its part of the air intake and the engines air goes through the MAF itself. It sits atop the air filter holder box (unless your intake is modified). There is an electrical connector attached to the engine side. Make sure that connector is firmly attached.
The above is the easy part. If everything is hooked up - well... then we get to have a lot more fun.
There are several ways to check for vacuum leaks. Your car's vacuum system is a plethora of rubber and plastic hoses and pipes that run all over the engine itself, and on a 89 they are mostly on the passenger side rear of the engine. Some extend out to the throttle body, one goes under the plenum, a few go off to the canister at the front passenger side.
Basically you inspect these hoses, making sure they are properly connected and there are no cracks, holes, splits, bad connections, etc. A vacuum system is exactly that - Your car generates vacuum (sucking), when it runs. The vacuum system supplies vacuum to parts that need it. When there is a hole, it reduces that vacuum and your car runs like crap.
Cruise not working can be several things. Number one to check is down on the brake pedal. You ought to have a bracket with a white plastic looking deal with a large vacuum line on it. If that vacuum line is not in place, its a HUGE vacuum leak, and your cruise won't work. On that same white dealie, theres another electrical connector. This tells the cruise module that you've pressed the brake, and to turn off cruise control. Its a normally closed switch so that if it isn't on, or the switch is broken - cruise will never work cuz it thinks your pressing the brake the whole time.
You have a cruise module (little box deal) behind the passengers vertical portion of the dash. I think stock birds had a map holder in that spot. The module is behind the plastic. Gotta pull the dash to see if its there and plugged in.
Cruise also depends on vacuum, so with a vacuum leak it won't work. There is also a wire going to the tranny that tells the cruise module how fast your going. Don't worry much about that one yet.
Here is some decent background info on O2 sensors in general: My own rule of thumb is to just replace it if I suspect anything is wrong. An O2 sensor is a wear item, like brake pads. They go bad after a few years, get tired out, etc. YOu should check to make sure the wire isn't broken.
You have an 89 2.8L. There is a very good chance you have a MAF car, (Mass Air Flow), vs. a MAP car (Speed density/ AKA Manifold Air Pressure). 1989 was the last year for the MAF's, in 1990, GM began putting Speed density in all the cars.
So you only need to pay attention to:
"MASS AIR FLOW (MAF) SENSOR - SIGNAL VOLTAGE OR FREQUENCY IS LOW DURING ENGINE CRUISE"
However, "During Engine cruise" bit is a wee mite wrong. Code 34 indicates "Signal voltage or frequency low" at ANY point, even without being at engine cruise. I can make a code 34 appear by unplugging my MAF's power/signal connector. MAF is basically a sensor that tells the engine computer how much air is flowing past it. The engine computer (ECM) uses that info to calculate how much fuel to supply to the engine. It does so by varying the length of time (usually in milliseconds) that the fuel injectors fire. More air means more fuel is needed.
Now think about the readings from the O2 sensor (which measures how much free oxygen is in the exhaust). That free oxygen amount indicates how completely fuel is being burned. In a perfect motor supplied with an exactly stoichiometric (big word for perfect ratio of fuel to air so that the fuel and the oxygen are both completely burned) mixture there is a certain amount of free oxygen. Too little free oxygen indicates a lean mixture (not enough fuel) Too much free oxygen indicates a rich mixture (too much fuel).
Combine the readings from the MAF which adjust fuel mixture and the readings from the O2 sensor which indicate how stoichiometric the mixture was, and you have the basics of how an engine computer works.
One thing to remember is that the engine computer stores codes as long as the battery is plugged in. If your car was started with either or both of these devices unplugged, than the code could have been set eons ago, and now they could both be plugged in and working fine, but you'll still have a code.
Start with a cold engine. Unplug your negative battery terminal for 5 minutes to clear the codes. Plug it back in and go for a drive. It'll probably drive like crap for 3-5 miles. Just go with it, the engine learns how you drive and what fuel mixtures are right during that first part. Then see if your codes come back. I hate chasing gremlins that aren't really there!
If they do both come back, the next step is to see if they are actually plugged in! Your O2 sensor is on the exhaust pipe, rather near the starter, its a cylindrical looking thing screwed into a hole in the pipe with one wire coming off about 6-12 inches long that goes into a connector somewhere up into the motor. Just follow the wire and make sure its plugged in.
Your MAF is on the air intake. Its a black plastic cylinder about 6 inches long and 2.25 inches in diameter. Its part of the air intake and the engines air goes through the MAF itself. It sits atop the air filter holder box (unless your intake is modified). There is an electrical connector attached to the engine side. Make sure that connector is firmly attached.
The above is the easy part. If everything is hooked up - well... then we get to have a lot more fun.
There are several ways to check for vacuum leaks. Your car's vacuum system is a plethora of rubber and plastic hoses and pipes that run all over the engine itself, and on a 89 they are mostly on the passenger side rear of the engine. Some extend out to the throttle body, one goes under the plenum, a few go off to the canister at the front passenger side.
Basically you inspect these hoses, making sure they are properly connected and there are no cracks, holes, splits, bad connections, etc. A vacuum system is exactly that - Your car generates vacuum (sucking), when it runs. The vacuum system supplies vacuum to parts that need it. When there is a hole, it reduces that vacuum and your car runs like crap.
Cruise not working can be several things. Number one to check is down on the brake pedal. You ought to have a bracket with a white plastic looking deal with a large vacuum line on it. If that vacuum line is not in place, its a HUGE vacuum leak, and your cruise won't work. On that same white dealie, theres another electrical connector. This tells the cruise module that you've pressed the brake, and to turn off cruise control. Its a normally closed switch so that if it isn't on, or the switch is broken - cruise will never work cuz it thinks your pressing the brake the whole time.
You have a cruise module (little box deal) behind the passengers vertical portion of the dash. I think stock birds had a map holder in that spot. The module is behind the plastic. Gotta pull the dash to see if its there and plugged in.
Cruise also depends on vacuum, so with a vacuum leak it won't work. There is also a wire going to the tranny that tells the cruise module how fast your going. Don't worry much about that one yet.
01-26-2007, 09:07 PM
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Wow, bobdole369. If you were standing in the same room as me I'd give you a hug. Thanks for the thorough tips. I'll try out what you said to do this weekend and I'll report back on or by Monday.
Thanks a bunch!
PS: I was driving it around today in the rain, and it's pretty cold outside (San Francisco, currently 47*). So what happened was I started the car, and my RPMs idle between ~800-500; usually it idles at ~1200-1500. But anyways, I put it in gear and when I slowed at a stop sign, the engine felt like it was going to stall out. Well, I kept driving and lo and behold, it stalls on me not once, but about 4-5 times. A couple days ago, I was driving it and it felt like it was going to stall again. However it did not, but when I started to do a turn going around 25 MPH, the engine just DIES. No stumble, no misfire, no NOTHING. The engine just turns off, and the only notice I get that it died is that my brakes lose hydraulic pressure and now I'm just flooring the brake to get my car to stop.
Is that an indication of something?
Thanks a bunch!
PS: I was driving it around today in the rain, and it's pretty cold outside (San Francisco, currently 47*). So what happened was I started the car, and my RPMs idle between ~800-500; usually it idles at ~1200-1500. But anyways, I put it in gear and when I slowed at a stop sign, the engine felt like it was going to stall out. Well, I kept driving and lo and behold, it stalls on me not once, but about 4-5 times. A couple days ago, I was driving it and it felt like it was going to stall again. However it did not, but when I started to do a turn going around 25 MPH, the engine just DIES. No stumble, no misfire, no NOTHING. The engine just turns off, and the only notice I get that it died is that my brakes lose hydraulic pressure and now I'm just flooring the brake to get my car to stop.
Is that an indication of something?
01-26-2007, 09:25 PM
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Wow, bobdole369. If you were standing in the same room as me I'd give you a hug. Thanks for the thorough tips. I'll try out what you said to do this weekend and I'll report back on or by Monday.
Thanks a bunch!
PS: I was driving it around today in the rain, and it's pretty cold outside (San Francisco, currently 47*). So what happened was I started the car, and my RPMs idle between ~800-500; usually it idles at ~1200-1500. But anyways, I put it in gear and when I slowed at a stop sign, the engine felt like it was going to stall out. Well, I kept driving and lo and behold, it stalls on me not once, but about 4-5 times. A couple days ago, I was driving it and it felt like it was going to stall again. However it did not, but when I started to do a turn going around 25 MPH, the engine just DIES. No stumble, no misfire, no NOTHING. The engine just turns off, and the only notice I get that it died is that my brakes lose hydraulic pressure and now I'm just flooring the brake to get my car to stop.
Is that an indication of something?
Thanks a bunch!
PS: I was driving it around today in the rain, and it's pretty cold outside (San Francisco, currently 47*). So what happened was I started the car, and my RPMs idle between ~800-500; usually it idles at ~1200-1500. But anyways, I put it in gear and when I slowed at a stop sign, the engine felt like it was going to stall out. Well, I kept driving and lo and behold, it stalls on me not once, but about 4-5 times. A couple days ago, I was driving it and it felt like it was going to stall again. However it did not, but when I started to do a turn going around 25 MPH, the engine just DIES. No stumble, no misfire, no NOTHING. The engine just turns off, and the only notice I get that it died is that my brakes lose hydraulic pressure and now I'm just flooring the brake to get my car to stop.
Is that an indication of something?
01-27-2007, 12:45 AM
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Car: 85 camaro sport coupe
Engine: 2.8 MFI
Transmission: v6 700R4 wish it was a 5spd Stick
Axle/Gears: Stock non posi 3.42s
If the car dies there is no vacuum and your brake booster will not work any longer cause its Vacuum operated. Id venture a guess as to you have some vacuum line thats bad and sometimes it will have more seal cold than hot(my car had this problem) and then when it warmed up it will leak. Fix the vacuum leaks and 99% of your problems will go away.
I got those 2 codes cause of bad vacuum leaks. Fixed the lines and they went away.
EDIT: if you your car already has Rubber line on it just replace it. If its the original line its probably bad and that line is REALLY cheap. As long as the plastic stuff is not broken it should be good but i have replaced most of it on my car cause it gets broken really easy when you go to fix something on these cars, which for me is a weekly activity.
I got those 2 codes cause of bad vacuum leaks. Fixed the lines and they went away.
EDIT: if you your car already has Rubber line on it just replace it. If its the original line its probably bad and that line is REALLY cheap. As long as the plastic stuff is not broken it should be good but i have replaced most of it on my car cause it gets broken really easy when you go to fix something on these cars, which for me is a weekly activity.
Last edited by xplane; 01-27-2007 at 12:50 AM.
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01-28-2007, 01:31 PM
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Wow this has to be my old car!! I had a 1989 Camaro v6 2.8 and it did the same exact thing. When i turned a corner it just died sometimes. I almost got in a few accidents coming off a freeway off-ramp. What color is it by the way.?
02-01-2007, 05:30 PM
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Ok... So I unplugged the (-) cable and waited, and as I was waiting, I went ahead and replaced the Oxygen Sensor. I reconnected the cable, drove it around all the while my SES light is on --this hasn't happened before--. Once I get back I turn the ignition off, plug in the code reader, and it spits out "CODE 33"...
No more Code 13 and Code 34. But now, my new problem is my MAF is getting too much voltage, and my idle sits at ~2000 RPM...
Anyone wanna help a brother out?
No more Code 13 and Code 34. But now, my new problem is my MAF is getting too much voltage, and my idle sits at ~2000 RPM...
Anyone wanna help a brother out?
07-31-2007, 07:54 PM
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Car: 1990 Firebird
Engine: 3.1....4159265
Transmission: 700r4
Axle/Gears: axle rose and metal gear solid
Re: Fault Codes 13 and 34... Help?
hello syko did you ever solve this problem? because now i have it i think its contagious
08-01-2007, 05:20 AM
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Car: 89 Camaro RS, 79 Firebird Formula
Re: Fault Codes 13 and 34... Help?
Had the same problem. Check voltage at the MAF plug. Black is ground, Light Blue is power from the MAF Relay (that's located next to battery), Brown/White is from the ECM (Should read about 2.5volts I believe). Key on Run.
My problem was intermittent. Ran ok sometimes, got rough and stalled others. Changed the MAF relay first since it was cheap. Then the ECM as it eventually became impossible to drive any distance. Runs almost 100% now. No more codes. I still need to work on it a bit but for now, that's what fixed mine.
https://www.thirdgen.org/forums/v6/4...ml#post3237597
My problem was intermittent. Ran ok sometimes, got rough and stalled others. Changed the MAF relay first since it was cheap. Then the ECM as it eventually became impossible to drive any distance. Runs almost 100% now. No more codes. I still need to work on it a bit but for now, that's what fixed mine.
https://www.thirdgen.org/forums/v6/4...ml#post3237597
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