"Service Engine Soon" during VCM rewrite?

[m_LeDez]

My first VCM rewrite attempt to adjust my idle went fine with no problems. I decided to try another idle target configuration. I followed the same steps as before, but this time I got a "Service Engine Soon" warning on my DIC during the rewrite process. I allowed the rewrite to complete, then powered down and disconnected from the port.

It wouldn't start on the first attempt, but started on the second attempt with no problems. I went out for a test drive and the idle performed just as revised. Curious, I made another change, walked through the same "Write Calibration Only" steps and during the rewrite....I got the "Service Engine Soon" message again.

Same thing, didn't start on the first attempt, starts on the second attempt. No other warnings, it runs fine and the idle at cold start performs as edited.

Is it normal to get that warning during downloading?

[jeff]

My understanding is that it is normal. The DIC cannot communicate with the PCM during a write and sometimes shows random errors. Everything is ok again after the write finishes.

[12secSS]

As jeff mentioned, it is absolutely normal. If you don't get it, then something is wrong.