Increased fuel consumption and reduced power

[wigwig]

I just finished replacing the head gasket in my ‘03 z4 3.0i, and it almost runs well, minus the problems described in the title. The check engine light is on, and when I scan it I get 2 codes, p16a1 (internal control module memory checksum error in application software) and a secondary code p1634 (throttle valve adaptation spring test failed). (The coolant light also won’t go away, even though the resevoir is full, not sure if this is related or something else). I have been searching the internet furiously looking for an answer, but I have barely found any mention of the primary code anywhere. I found a lot of people resolving the secondary by cleaning the throttle body, but I just cleaned it before I put it in over the weekend. Any help is appreciated, much thanks!

[pungo]

Not sure what "internal control module" it's referring to, but with a "checksum error" the software is corrupted, so who knows what kind bizarre issues could happen

• Did you scan for error(s) before beginning your work?
• Did you disconnect the battery before beginning your work?
• Did you use ista+ to diagnose the fault(s) the follow the recommended test plan?

[wigwig]

Originally Posted by pungo

Did you scan for error(s) before beginning your work?

Yes, right before I started the job I only had a cyl5 misfire code, however about a week before I started I got this same weird code when the car broke down on me while I was driving, but it went away after I started it up again.

Originally Posted by pungo

Did you disconnect the battery before beginning your work?

Yes, the negative terminal was disconnected while I was messing with the engine.

Originally Posted by pungo

Did you use ista+ to diagnose the fault(s) the follow the recommended test plan?

I’m not sure what that is (I’m assuming some kind of scan tool or software?), could you share a link so I could try that?

[pungo]

Originally Posted by wigwig

I’m not sure what that is (I’m assuming some kind of scan tool or software?), could you share a link so I could try that?

The concerning part is the checksum error since that means one or more bits in the firmware has changed from what is expected. It may require re-flashing the module to overwrite the corrupted code

Yes, it's diag/scan software and requires a window machine and a $20 OBD cable link

[wigwig]

Originally Posted by pungo

The concerning part is the checksum error since that means one or more bits in the firmware has changed from what is expected. It may require re-flashing the module to overwrite the corrupted code

Yes, it's diag/scan software and requires a window machine and a $20 OBD cable link

Thanks, I’ll look into that software. Is re-flashing it something I can do myself? Or is that something I would have to take it to a dealer for?