General questions

I have a 2000 Chevrolet Malibu. In any of the scan tools that I use, in the enhanced parameters I see an 'accelerator pedal position' parameter which is stuck at 3% and throttle position stays stuck at 0%. However when viewing the throttle perimeter and generic OBD I can see its position relative to my foot. Also to my knowledge I don't think this vehicle has a pedal sensor since this doesn't utilize drive-by-wire.

Anyone knows what could cause the enhanced functionality not to work properly? I've tried a few expensive scan tools as well as a few Bluetooth ones.

Also, what might cause an EGR valve to sometimes remain open at idle and Park with values of sometimes 4% and 9%? I was getting a stuck closed performance error the other day but I took it out and cleaned it to the best of my ability. Desired EGR position is always at zero When these values are seen in idle or Park.

Related to bypass testing: when determining circuit design weather pull up or pull down, the control wire in most cases is the wire that would always be used for testing right? Example if a circuit is pull down in the wiring that goes to the solenoid is ground side switched what does be a simple matter of taking the test light on battery positive in applying it to that wire to control the solenoid etc and test light to ground to the control wire if its a pull up design? Hope i understood that.

Hey sir! I remember having some difficulty with getting reliable data from your Malibu... You're right, there is no APP, dunno why it's even showing those PIDs

Which scan tools have you tried, specifically? What kind of options are there for identifying the vehicle you're working on? Mostly wondering if the scanner thinks it's looking at a newer Malibu for some reason.

The enhanced scan tool functionality problem is weird, too. No history of PCM swapping? The network your Malibu uses is pretty straightforward, and pretty good at diagnosing comm issues on it's own. If you're not finding U1000 series codes in any modules, then I'm inclined to think the vehicle side of things is OK.



Your EGR code, was it P1404? The problem is likely to be in the valve itself - either the valve truly is sticking open, OR the potentiometer inside the valve is failing. A good test for this would be to have the scanner connected with the key on, and watch the valve position while using jumper wires to operate the valve. If you can get the EGR Error % to vary by 'popping' the valve open/closed, then it's not looking good for the valve. Your scanner may have a "Linear EGR" functional test available, too, which would do the same thing.

Dunno if you've seen this ScannerDanner video, but it covers the P1404 error code very nicely. Not saying that you're having the exact problem as seen in the video, just using it for informational purposes.



About your bypass testing question: I REALLY don't mean to nitpick here, but I think some of your confusion may be related to the terminology used. 'Pull up' and 'Pull down' relate to switch inputs, while power and ground side switching refer to outputs. I've caught myself mixing the terms together, and I realized that I was only confusing myself more because of it.

In your example of a ground side switched solenoid, then you would want to use your test light connected to B- on the control wire to operate the solenoid, as the ground is what the engine computer will control to operate the solenoid. In short, this test is useful when you want to check operation of a solenoid, or operate it manually for testing purposes. Using your test light connected to B+ in the same situation would only confirm if the engine computer is actually providing that ground or not. Again, in short, this is useful for checking wiring and driver integrity.

Did that help? :blush: Don't hesitate to ask more questions if you're still not sure!

Hey thanks for the reply

The scan tools ive tried were a friends auto engenuity, some bulky old scanner/pc interface ( cant remember the model), torque pro and car gauge pro android apps with the bluetooth dongle. Wish i could try a verus.

Im not sure if the pcm was swapped prior to purchsse. Guess it would be a good idea to get a carfax report.

the egr code indeed was a 1404. the only parameters available to me are egr volts, desired position, duty cycle, and actual position.

Thanks for the correction on the testing part. i have more questions and will pm you if thats ok

Hmmmm, I'd expect the AE to get good data out of this thing, at least How about this: Do the VINs on the door and on the windshield agree? Thinking about if the door got swapped, and isn't correct for the vehicle. It's a long shot, I know!

As far as the P1404, the EGR volts, desired position and actual position will work fine for testing purposes. Basically, the closed position voltage shouldn't vary no matter how many times you operate the valve. A few hundreths of a volt would be OK, but no more.

No problem, feel free to message away!

Sent you a message

I know :blush: I actually had a response ready TWICE yesterday, but the forums kept logging me off and deleting it I had to walk away before I got too frustrated, lol.

Check in later today! I'll have a couple PM's for you.