Drove to work yesterday rainy and 34 degress but no problems (drove the car 2 days before that in colder dry temps and ran 100%) , on the way back nothing was out of the ordinary and then the car shut off at a light. Started it back up and it was running barely like in limp mode. Well barely made it home it was running really rough and sounded like I had heads and cam but the car could barely accelerate. Almost home and the SES went off and the car rode normally. So I figured maybe some rain got under the hood and then it dried up.
Well took the car to work today still cold and rainy and the car ran fine for about 5 miles (15 minutes) and then it went back to acting bad.

Anyway something is going on and never had this many error codes at once.

15 Coolant temperature sensor signal indicates a temperature colder than -38� F for 3 seconds.

21 TPS voltage was above 2.5 volts for 3 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or TPS was above 4.5 volts at any time.

23 Manifold air temperature sensor signal showed an air temperature below -22� F for 12 seconds after the engine has been running for 5 minutes.

43 The ECM did not detect a knock signal during near wide open throttle operation, or the knock sensor voltage was above 3.62 volts or below 1.44 volts for 0.5 seconds.

53 ECM sees a battery voltage either above 17.1 volts or below 8.0 volts.

I guess I have alot of testing to do soon, cant drive the car in this condition, it was puffing out alot of fuel/smoke so my guess is limp mode for sure but so many error codes def. has me confused.

 

First thing I would do is check your engine ground. Multiple codes like that, first suspect.

 

The second thing to check is to make sure all connections are clean, tight, and water proof. One or two codes indicate possible component failures. A laundry list of codes on a car that was running good indicates a bad ground and/or bad or dirty connections.

 

Did some testing found no visible loose grounds anywhere, everything looks to be in order and fine, it must be something when the car gets to closed loop a sensor or two has gone bad. Yanked out the battery and tested it and still strong. Started the car back up and it ran fine for a few minutes then when I guess it hits closed loop things go hay wire, the car magically shut off will idling at 1k idle a few times, then started it back up and bam back to spewing out black smoke/ raw fuel and idling like I have a massive cam.

I have dismissed a few codes and going to focus on 15,21,23.
The ecm most likely once it hits closed loop and trying to figure out the engine temp and most likely the CTS has kicked the bucket. Cant image the TPS going up all of a sudden however, you never know. Never had any of those codes before and find it weird, but this is a thirdgen and this happens all the time

15 Coolant temperature sensor signal indicates a temperature colder than -38� F for 3 seconds.

21 TPS voltage was above 2.5 volts for 3 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or TPS was above 4.5 volts at any time.

23 Manifold air temperature sensor signal showed an air temperature below -22� F for 12 seconds after the engine has been running for 5 minutes.

X 43 The ECM did not detect a knock signal during near wide open throttle operation, or the knock sensor voltage was above 3.62 volts or below 1.44 volts for 0.5 seconds.

I have gotten this a few times, by itself it would not cause the car is run this bad for sure, so I am dismissing this code for now.

X 53 ECM sees a battery voltage either above 17.1 volts or below 8.0 volts.

Battery checks good and the alternator is charging normal so I am dismissing this.

 

Did you clean off the ground connections, or just check for tightness? Rust is a bad conductor.

 

I did both, used degreeser than electronic cleaner as well as moved them around some to get a fresher connection. Also used electronic cleaner on connectors of the CTS, MAP, and TPS.

I wish I had my chip tuning equipment and laptop, but my laptop broke and my tuning stuff I gave to someone.

I also went through all my fuses, as well as pulled my computer to make sure my chip was in there tight as well as ecu connections.

 

Did you check your battery cables? Good connection? Not broken, burned, etc?

 

Yeah battery cables went on fine, the car was just running and I did nothing to it, which leads me to believe something electrical like a sensor.

might start off with a new CTS and see what happens.

 

take the connectors off the computer with the bat disconnected and wipe a layer of dielectric grease

grease all the terminals on the motor

it could be one of the wires that are pink and black that goes to your computer not geting the 12 volts it needs

there is also a connector under the pass side of the dash that has all the power wires going to the computer

how did you dismiss the ecm voltage bieng off because you are getting power to the battery and altenator

if you dont have a voltsmeter its time to spend 15 bucks

 

I agree with jamon8 it is always less expensive to find your trouble by trouble shooting the problem than it is to start swapping parts by the "by guess or by gosh" method. It may be time consuming, but checking voltages will pin point where the trouble is and save you buying extraneous parts that are not needed.

 

Started the car from full cold and just let it idle in park roughly about 10 minutes it cut off while idling at 1k rpms. it did it again and then again. Then I started it back up and it got real rough again barely running idle bouncing up and down, blackish smoke, etc...limp mode in my opinion.

Anyway I ran the codes this time and I got only 43 and 53 this time. My guess is that since I wasnt driving the car I wouldnt get the other error codes for the CTS, IAT, and TPS.

However I apparently need to focus on this code 53.

Now it seems more voltage related.

After seeing 53 again, if the ecm is seeing too low volts things wont work correctly, I cant image how it would see 17.1 volts, other than massive overcharging by the alternator.

 

Have your alternator tested - sometimes they have an issue with random 'spiking' of voltage when they get old. Its not really common, but I've seen a couple like that. It may in fact actually be seeing too much voltage in the form of a spike. It won't show on the guage, because its too quick and the guage is too lazy to react quickly enough to show it. What does your guage normally read?

A bad connection somewhere - power or ground - can also cause an intermittent problem like this, as it could be breaking the circuit momentarily or causing alot of resistance, making the power actually getting to the ECM very low... a rusty/corroded or loose connector or mating surface can cause this, as could an overheated or burned wire (overheated/burned wiring has alot more resistance than good wiring). You can ID a burned/overheated wire by flexing it... good wire will bend and then spring back to how it was before, but an overheated wire will be stiff and hold its shape when you bend it, sorta like a paper clip.

Check the actual voltage at the power wire to the ECM, see if its doing anything goofy while the car is running. This could reveal a spike or unusually low voltage, which you'd have to track down.

Are your battery cables/terminals/posts corroded? Does the alternator get hot after it runs for awhile (like, too hot to touch)?

 

I pulled the alternator and battery getting it checked out soon.

I checked the main wires going to and from the starter, alternator, and battery and nothing seems to be out of place. I was noticing my hood insulation holding water and I assume leaking some into the alternator maybe.

I havent replaced the alternator or battery ever, they been working ever since I bought the car in 2002/2003 when it had 62,xxx miles, now I have 106,xxx miles so it might be about time.

thx.

 

Alternator and battery tested good.

Even the guy at the Autozone said most likely its a ground problem especially since its a gm.

The closest problem, if its a problem at all, is that the main wires under the passengers header mostly the ground wire looks like it has been heated up alittle bit over the years but other than that, havent found anything substantial yet.

 

you need to go under the dash

thats what she said

pull the computer down and take the two connectors down and spread the dielectric love.

I do this to all my cars

every sensor smear some on

clean the grounds

replace the altenator to battery wire

so on and so on

 

Thanks I will give that stuff a try, its just odd that it takes a few minutes to start acting up and not right away, darn thirdgens always breaking during the winter.

 

It doesn't start acting up right away because the ecm does not start to read sensors until it goes to closed loop after the oxygen sensor gets warm enough to go in range. In open loop it uses factory presets without regard to what the sensors are telling the ecm.

 

Small update:

Lubed the computer harnesses with di-electric and various sensors and still got the same thing going on.

It starts right up when full cold and then roughly 4 to 6 minutes sitting there idling fine it will just cutoff. I start it back it and a few seconds it cuts off again, then I will start it back up and it starting running horrible (limp mode) spewing out black oil/fuel residue out of the tail pipes I had to block the stuff coming out because it was hitting my other car almost.

I wish I had my laptop and tuning stuff but I dont. I got the same codes roughly 15,21,43, didnt sit long enough to wait for any more codes had to get ready for work.

I looked everything over wire wise and things look fine. Maybe the sensors mostly the coolant temp sensor just needs to be replaced, I dont think I changed that yet. It has a 3 year old tps, iat, and map. It seems it cant find temperature and things go haywire. Since I didnt touch anything one day it works fine and the next it doesnt I have to guess its a sensor for the most part. Starting with the CTS and work from there.

Almost feel like locking it in open loop

Something is done for sure!

 

I would follow the wiring from the TPS, CTS, and knock sensor... follow it all the way back through the firewall and see what you can find. All of those codes indicate 'weird' voltage readings, which says to me one of two things (assuming the batt and alt are indeed OK) - either those wires are shorting to ground somewhere, or they all use a common ground (possibly engine ground?) that is having problems. See if they are burned, cracked, broken, pinched, or rubbed through anywhere - most likely spot would be where they go past the firewall, or around exhaust parts. Check the engine grounds by actually removing them, cleaning the connectors with a steel brush, and cleaning the mounting hole surface with a steel brush. Make sure the metal is CLEAN.

If you have a voltmeter, you could check the voltage at the TPS and CTS when the key is on, and when the engine is running... see if they are withing the correct range. You can find those specs here somewhere.

 

check all the pink w/black stripe wires that go into the computer with a voltmeter

sorry you are having so many problems but if these cars were easy to work on everyone would have one

keep your head up and you will find the problem

a helms manual will help you as well

 

Small update:

Decided to throw in a coolant temp sensor, the new one tested out at like 3.6 k ohms, and my old one tested at a very different number like 6.8 k ohms.

Put it in, pulled the ecm fuse and battery, put everything back together, started right up like normal full cold, and it was just sitting there idling for 3,4,5, 8 minutes. So I said wow maybe its fixed, decided to drive it. Went around the block, then the neighborhood. It was running like 15 minutes and was running full warm for like quite a bit. So I decided to get on the gas alittle bit roughly 4 k rpm and then it shut off, then I thought well maybe the idle didnt catch it. Nope turned it back on and it was in limp mode now with the SES light back on

Weird!!!!

Running out of ideas, time to buy another beater I guess.

 

codes 15, 21 & 23, will set right away if the ECM sees a problem.
43 will normally set within about 10 seconds of key on if the ECM sees a problem with it.
a wire shorted somewhere can cause the problems your seeing. check the 5 volt reference when its acting up.
if you could check the scan data it could be a big help, during the event if the ECM reports a voltage much higher than battery voltage with the key on engine off, a bad ECM is highly likely.

try tapping on the ECM when its running bad.
if it starts running right, recheck all the terminals and the wiring near the ECM. if you can't find a problem with them, your ECM may well be dying.

 

Very good update, should be fixed now!

Replaced the ecm with a oem reman. from advance auto parts.

$80 bucks plus I gave them my old one, good deal.

Put in the chip and plugged it in and started her up. Started up fine like normal, let it idle and hopefully at least do what it did yesterday and idle to full warm and it did. Now I decided to go for a ride just like yesterday everything was going good just like yesterday. Now I decided to get on the gas just like yesterday and bam it took it like a champ this time and everything is now going good. Went for another ride and things seems to be great now. Even the fan came on when it was suppose to so it reading temps fine and everything.

So countless hours of testing wires, connectors, grounds, voltages, $80 and its rolling again.

Kinda weird it was the ecm, my guess is that a pin or more was going lose or maybe worse. Maybe getting the knock sensor code over and over again was a sign something was going amuck because the connector has voltage and knock sensor in spec and the connection was good. It might of been the yanking out the ecm quite a few times while chip tuning causes a pin or more to come lose on the board.

Taking it to work tomorrow and see what happens. Felt good to drive it again.

Thanks for all the suggestions and help.

 

good job

makes you enjoy the car in a different way