Hi All,

Recently, I have been having a series of problems with my balt.

2005 Balt SS / 5-speed manual / 115k miles

First, I got caught in the flooding in Texas. Floorboard dried out with a little help and there were no other issues, so I considered it a done deal. Then my power steering went out. I figure its just the recall so I scheduled a time with my local dealership to have the recall work done.

Then I started to notice a significant loss of power. The previous owner gutted the cat and deleted the muffler, so people tend to hear my car coming from a few blocks away. However, last couple days I noticed the rpms jumped or dipped at idle. Under throttle, it seemed normal. Then I noticed I would have to rev higher than normal to get up to speed. Most recently, I left my car running and jumped out to check it all out. The car was almost completely silent (usually very loud even while idling under no load). I checked the exhaust and I could barely feel anything coming out. Then Friday, it died on me. CEL light popped on, along with the dreaded "ENGINE POWER REDUCED" message. Engine turns over, but won't start. And if it did start, it would just stall out.

I disconnected the battery and waited for the security reset. Started her up and she ran. Except that the exhaust pipe now rattles (I'm guessing something shook loose from the violent shaking trying to start it up previously). I drove her about 50 feet before she started sputtering and died. After that she wouldn't to start back up.

After reconecting the battery and before trying to drive her, I was able to pull the following codes:

P0603
P0606
P1680
P1681
P0603PD
P0606PD
P1680PD
P1681PD

Now, I won't pretend to know everything, and I don't understand the sigificance of the duplicate codes, but I figure the first code is simply from disconnecting the battery and the rest point towards the ECM. At the same time, my bro-in-law says he had a similar issue with his 2.2l ecotech (saturn vue) and thinks it's just the ICM. After reading the forums, I'm not clear on if there even is an ICM for my balt (or if that function is handled by another _CM) or where it is located.

If anyone has experience with this issue, and can confirm if it is the ECM or ICM or PCM, wiring harness, or something else entirely, please help. I love this car, but in light of recent issues, I can't justify keeping it with my wife.

Edit: Also, this is our only vehicle currently. We are having non-related issues getting our (her) car to Texas from Hawaii.

 

Ecotecs do not use an ignition control module. The functions that an icm would perform are done with the ecm. 2 of those codes are for internal module failure of your ecm. One is for throttle position performance, one if for accelerator pedal performance. That p0606 is internal memory fault. I'd start by replacing your ecm before i worried about if those throttle postion codes are accurate as generally an internal memory problem with the ecm will cause it to go bonkers.

 

From my experience its usually the other way around. Something else being wrong will generally cause p0606 to set because it is getting false inputs. How deep was the flood water?

 

Area wide, the water rose to the side skirts. However, there was an unavoidable puddle that it went through. Water came in through a hole in the firewall and soaked the carpet around the pedals. Other than that, there was no real flooding, though I'm worried everything started after that happened.

Edit: Car tried to stall out but I made it through without it dying on me (at that time).

 

I'd start with a throttle body, but if you got the electric gas pedal wet it could also be damaged.

 

Is there a way to test the gas pedal?

As for the throttle body, would it be better to bathe it in throttle body cleaner, or just replace it? Or will that have to be determined after removing the s/c and getting eyes on?

I appreciate all the help. My budget is very minimal. Is there a way to test any of these things before disassembling things? I'd like to pinpoint the problem without having to buy parts and install them only to return them and get something else (though I know that's how it usually goes).

Thanks

 

You can test the voltage inputs and outputs from the accelerator pedal position sensor(APP). I wouldnt go "bathing" an electronic throttle actuator in anything

 

Fair enough. Maybe "bath" was the wrong adjective. But from what I've read, the TB is a weak link in this engine. I'll be getting in there to see if it needs cleaning soon. Is it possible that a dirty/gummed up TB would cause my problems?

 

the l61 uses one

 

So I got my intake hose off and there is gunk everywhere. Butterfly looks like it is stuck open. I'll be removing the throttle body tomorrow and cleaning it. Hopefully that fixes my problems.

 

If the engine is off the throttle plate will be open

 

Okay, so I cleaned the throttle body. I'm idling around 1k (normal was ~750 prior to all this). Car starts up and will drive for a short while (50 feet or so) before it just dies on me. RPMs just drop to 0 and engine is off. I'm clearly out of my element here. Any suggestions?

 

No other codes? It won't die if you leave it idling, only when driving? Any other changes when it shuts off? Do you notice the gauge drop to zero immediately, like while the engine is still winding down?

 

Disconnect the battery for a half hour to reset the throttle learn

 

Quick update: I bought some electrical cleaner and cleaned all the connections to my ECM. After sitting with the battery disconnected while I cleaned (and then some) I started her back up. She sounds the same (like she wants to roar, but just can't get there). Feels muffled and I can still feel a distinct shaking. When I give it gas (while parked) it's almost like she hesitates before revving weakly. I can feel the heat from the exhaust (and light pressure) but nowhere near the flow or sound level as before.

She will idle around 1k no problem. After revving hard and letting go, she will look for idle and dip almost to the point of stalling out. We idled her for about 10 minutes trying to see if she would work herself out.

After disconnecting the battery, I did expect a security relearn, but nothing happened and the padlock light never came on, though the CEL did.

After cleaning the connections and starting her up, I've got only 1 code popping up now. P0603. The others have since gone away.

Is it likely that my problem is a bad ECM and it needs to be replaced? I can think of nothing else it could be.

Thanks for all your help so far, guys. I really do appreciate it.

 

Is the exhaust restricted? It sounds like when you have a catalytic converter that's melted or when someone runs over a rock and crushed the tubing down almost closed. Only enough air gets by to sustain idle, any more throttle and the combustion gases back up into the engine and choke it out.

 

Thanks, ItalianJoe1. I hadn't thought of that. I'll get it up on jack stands this weekend to look over the exhaust.

When I'm parked in neutral, I can rev the engine without it dying on me. When I release the throttle is when it drops and seems to almost stall out. When in gear and driving, it won't make 50ft before dying on me.

 

I'll confirm the P0603 is only from disconnecting the battery later after starting her up a few times and clearing the code. So most likely the ECM is not my problem.

Would a restricted exhaust still shoot out hot exhaust? When I let her run for a while the other day, the cat never glowed, but I was also not able to do much more than idle. However, it seems like my exhaust is shaking now (new developement). I can clearly see the cat and the bend just below it shaking when I looked under the car. Is it possible for the exhaust to shake itself loose if it is restricted?

 

It will be hot just weak flow on a badly restricted system. It revs out all the way to redline if you floor it from idle?

It could start to break down the flex section with enough pressure and you'd see vibration of the engine shaking the pipe around anyway. It's also probably not running perfectly with whatever issue it's having, causing a rougher idle.

 

Update: I did get the car up on jacks this past weekend. I didn't see any external damage (no crushed or loose pipes). I disconnected the battery, cleaned the connections to the ECM, and cranked it. Surprisingly, there was no security relearn. I let it idle for 10-15 minutes. I would occasionally open the throttle to about 2500rpm (cruising speed). The cat got warm, but never to the point where it changed color or glowed. This is what it looked/sounded like:


Assuming (hoping) it was the ECM itself, I went ahead and ordered it ($100 from ebay programmed with my VIN). That should be in today and I will see if it fixes my problems. Once I ordered it last week, I forgot to come back here and leave an update.

This morning, I cranked it up and revved it up. I noticed it choked out about 3500rpm. I might try in a bit to see if it does the same thing a few more times. I was able to drive it a short distance keeping it in first and keeping the rpms low.

 

If this doesn't fix your issue. Unbolt your exhaust before the cat and and try again. Since your exhaust was sitting in flood water it's entirely possible your exhaust internally rusted out and started falling apart inside. Had that happen to a local friend where his cat basically imploded. He had similar issues.

Im assuming you checked your intake filter?

 

Yes, air filter is fine. I checked it while it was on jacks just to be sure.

The bolts look rusted so I will have to buy replacements before I try and take these off. That's the only reason I didn't take off the exhaust to look inside the pipes. (That and the top downpipe flange looks like a bitch to get to...).

I did get a P0300 (misfire) code after messing with everything. But after I cleared it, it never came back.

After I install the new ecm, I'll report back here, whether it is good news or bad. On the bright side, the ecm is out for delivery with USPS!

 

Final Update:

I installed the new ECM. Didn't fix anything. Surprisingly, I also never had to do the crankshaft variation relearn, only the security relearn.

Eventually, I got the car home and took off the downpipe. Started her up and ... no problems. Gutted the cat and bolted everything back together. She's slightly louder now than before, but not by much. (Previous owner deleted the muffler.)

I switched my original ecm back in and the engine started rattling. I'm guessing the ecm was going bad and that (along with the water) is what clogged up my cat. So the new computer is back in and she is working great.

On the plus side, I managed to find someone selling a zzp 2.5" catback, zzp 2.5" catted downpipe, and a shorty header for roughly 130 shipped. That should quiet her down a bit as well as give a nice little bump to the power. I'll be bolting that on hopefully in another week or two.

Thanks for all the help, guys. I went in circles always going back to the cat. I should have just checked that in the beginning to avoid all the trouble. Learn from my mistake.