P1219, P1577, P1578 (accelerator potentiometer)

These codes popped up last night. Does someone have the troubleshooting steps? Thanks in advance!

Did these appear out of the blue of after the car was worked on? My diagnostics manual is packed in a box and unavailable to me to refer to. The 1st 3 codes are pretty clear as to what system -- e-Gas -- is involved. The last 2 codes point to a fueling problem and MAF comes to mind. But I don't like to believe that both the e-Gas and MAF failed concurrently. With the e-Gas system, the system could just have failed outright although I'd be inclined to check the connections of the e-Gas system before I blamed the hardware. For the suspected fueling problem, the MAF is possibly to blame. But like the e-Gas system before I blamed the hardware I'd check its connections first. You could look at various derived values like air flow reading and actual readings from the e-Gas system like voltage values from the various e-Gas potentiometers and throttle position sensors. A generic OBD2 code reader/data viewer will not allow you access to these readings. Thus you will need a Durametric tool. But with the error codes you know the readings/values are implausible so I'm not sure what additional insight you could gain from looking at these readings directly. If you find nothing with the connections then your next steps are limited. I hate to throw parts at the behavior because the parts are likely expensive. A new MAF can run upwards of several hundred dollars and I don't want to know what a new e-Gas system or throttle body costs. Clear the codes and see if they come back I guess. Or you could take the car to qualified shop with the proper diagnostic computer system and access to the factory diagnostics steps to pinpoint the root cause of what is going on.

Hi there Macster. Yes, this happened after I constructed a custom intake to the supercharger system. The length of the air pipes are almost the same as the supercharger OEM. I just decided to make air filter much more accessible. Based on advice in another thread, I put a honeycomb mesh right before the MAF, in effort to smooth out the airflow. Before this rendition of the intake, the only codes I had were related to O2 sensors. I think I'll bite the bullet and buy a new MAF. Using a Durametric, I logged real-time values of the throttle positions, etc. The data is quite useless, though, without some factor baseline data, by which to compare the values. I suspect an intake leak, but I'll be damned if I can find it. I need a fogger machine... guess I'll take it into the shop. Hmmmm, I was welding the exhaust tips last week. I disconnected the battery before doing any welding. What are the odds that my ECU custom flash became corrupt? Yep, reaching for straws at this point I'll update this thread once I have the ECU real-time data represented in a readable format.

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Well, that changes things. Putting the honeycomb mesh in front of the MAF is a good idea, but it may not have the desired effect. Intake air flow is very important and laminar air flow through the MAF is likewise very important. A supercharger really causes the air to tumble about which can upset the MAF. I really do not think it is the MAF though I know that Turbo's with engine mods that boost HP take their toll on MAFs as the MAF is begin asked to measure the mass of air flow way above what the stock engine requires. Some of these owners have gone to a MAF-less setup. Generally for a suspected MAF problem one can disconnect the MAF at the wiring harness and then drive the car and see if the symptoms/behavior that is suspected of begin due to the MAF still occur. Did the engine behave with the intake system that came with the supercharger? If so then you probably are going to have to put it back on. While you want air filter more accessible the supercharger maker probably found out the hard way that was not doable which is why the intake came the way it did. Intake leaks also can cause problems. I've never supercharged an engine but I added a dual side draft Weber carb setup to one engine and getting the intake leaks sorted was real work. I do not think you damaged the DME when welding. Since you disconnected the battery before welding on the car, what might help is to perform an e-Gas calibration operation. Turn the key off. Keep your foot off the gas pedal. Turn the key to on and leave it on for 60 seconds. After 60 seconds turn the key off. Leave it off for 10 seconds. Done. You can go over on the 60 seconds and 10 seconds times but not under.