Electrical issue with ECM?

[Joelee]

Hey guys, just joined and this is my first post.

I am hoping there are some knowledgeable member here that could help me out with a few issues i am having. I recently took a gamble and bought a 2008 Saturn Astra that has really low mileage but has an issue where the car starts and runs but after running for a little while it starts running rough and won't respond to pressing the accelerator, it is an intermittent issue, sometimes the car starts and runs ok but most times you can start it and in a minute or so it goes back to that above stated issue. also at times the emergency 4 way flashers start flashing and won't respond to pressing the button to turn them off but they usually turn off on their own in short time (5-10 flashes).

The alternator was swapped out with a used one due to the car being parked for approximately 6 months and the original one seized.

My questions are as follows:
1- does any one know if both of these issues could be a result of the ECU failing?

2- If not has any one else had any of these issues and successfully repaired them and if so how?

3- if I buy a used ECU, can i programme it to be compatible with the current immobilizer and keys and if so do I take the ECU and information to GM to have it re-programmed or should I install it first and then take the whole car to them?

Thank you for any help you can provide .

[billysvue]

?'s

Is the alternator charging?
Is the battery accepting a charge?

voltages resting and running?

batt clamps and posts cleaned?
When it's driven, how far/ how long?

[Joelee]

Yes, the alternator seems to be working fine. The battery is new as well.
It's a bit weird but when I start it and it runs fine for a minute I can go ahead and drive it and might not have an issue but usually I start it and wait a minute and it all of a sudden it will start to idle rough and I press the throttle peddle to the floor and it has only a very slight reaction like maybe 100 rpms more of that.

I went today to pick the car up from the guy I bought it and the first 3 times I started it, it acted up and I thought I would have to tow it, the forth time it started right up and ran fine so I got in and drove 25 kilometres home without any problems, I pulled in my drive way shut it off, when I started it up again it was running bad again.

[Joelee]

I went yesterday and got the codes read and they were as follows:
P065E- Intake manifold tuning valve performance (bank 1)
P0121- throttle/pedal position sensor A circuit range/performance
P0221- throttle/pedal position sensor/switch B circuit range/performance
P0138- Oxygen sensor circuit high voltage bank 2
P0642- Sensor referance voltage |A| circuit low
P0650- Malfunction indicator lamp control circuit malfunction
P2176- Theottle actuator control system | idle position learned

Would anybody be able to decifer this and tell me what's going on here?
I went to a local scrap yard and bought the pedal and sensor assembly and tried that with no luck, it's possible it was defective but not sure, I bought a BCM and tried that but it didn't help.

[Joelee]

Not getting much help here but I figured I would keep everyone updated with the results anyways. I brought the 2008 Saturn Astra to theGM dealer today and they gmfound the issues to be the "Intake Manifold Tuning Valve" which requires you to change out the whole intake manifold. They wanted $950 for the intake at GM and it between $650-750 to buy on line, I went a different direction and tried to buy one at the auto wreckers, they never had any so I bought the whole engine from them just to get the Tuning Valve. I'll be picking it up tomorrow and I'll keep you all posted o how goes.

[fdryer]

Unfortunately, you found out that not everything is plug n' play. Specifically, the ecm/bcm/throttle actuator and pedal don't lend themselves to quick replacement. When factory theft deterrent programs like GM's Passlock or Passkey are used along with drive by wire systems, unless you're willing to buy service manual having more informative than Haynes or Chilton, guessing can be an expensive attempt at repairs. Throttle actuators are calibrated, or better described as needing to be tuned to the engine control module that commands the actuator's throttle plate. The electronic pedal supplies position signals the ecm needs to command throttle plate position. Calibrating these components are needed when replacing them. The same when attempting to replace the ecm.

The ecm has part of the theft deterrent program to communicate with the body control module that has the main theft program, Passlock or Passkey, to check security. When either ecm or bcm are replaced, another procedure is needed to marry these two components together otherwise the fuel password isn't learned and the bcm sends a fuel disable signal to tell the ecm not to allow fuel operation. This can be either disabling the fuel pump and/or disabling injector operation. Other theft deterrent systems disable the starting circuit (Ions).

While you may not be aware of security and how integrated it is in EFI systems, you may have triggered some of the error codes (false errors) from incorrect procedures. Not retrieving the error code(s) from the beginning can send anyone into any direction without a clue. In some cases, performing a manual reset at the beginning of problems can help - erasing false errors while the real errors remains. Ecm's aren't the same as pc ecu's that sit in a stable environment (indoors) where ecm's/pcm's suffer from weathering effects requiring more attention to rugged design to survive. My ecm sits on one side of the engine to absorb freezing cold and summer heat along with heat from the engine - an amazing feat for GM to let the only engine computer sit on top of the engine without failing. To date no one has ever reported their ecm failing in L300's.

The intake manifold tuning valve, despite being told its not a replacement part without replacing the entire intake manifold, is shown in the service manual to be a replaceable part by itself. And may require programming to the ecm. Subscribing to alldata or Mitchell is more cost effective than throwing parts at the car especially when holding onto one. Monthly subscriptions are reasonable and If I'm not mistaken not subject to yearly contracts. You'd have to check to find out.