P0103 set, action taken?

[Boost]

I am working on an LS1 that has hard / current P0103 (Mass Airflow / MAF sensor circuit high) set. The mechanics tried replacing the sensor several times... :doh: Anyway my question is, what is the action taken by the PCM? Could it be that it stops looking at the MAF and defaults to speed density? Reason I ask is because it was MAF tuned for mods but gets poor fuel economy and nearly stalls from excessive fuel on deceleration. Thanks

[joecar]

Disagnosing P0103 (http://www.gearchatter.com/viewtopic9068.php)


On presence of any of the MAF DTC's the PCM stops using MAF and uses VE only (yes, speed density).

[Boost]

Just as I suspected, thank you so much for your phenomenal replies Joe!

[Boost]

Disagnosing P0103 (http://www.gearchatter.com/viewtopic9068.php)


On presence of any of the MAF DTC's the PCM stops using MAF and uses VE only (yes, speed density).

I won't move much further until diagnosed and repaired correctly, just wondering though - seems they tried to block it. In my experience this usually does not prevent PCM from defaulting to VE (?)

[joecar]

MAF DTC forces PCM to use VE/SD...

if you set the DTC to Not-Reported, then PCM will not use VE/SD, it will continue to use the MAF (or try to).

This is why you want VE to be properly tuned/corrected.

[Boost]

MAF DTC forces PCM to use VE/SD...

if you set the DTC to Not-Reported, then PCM will not use VE/SD, it will continue to use the MAF (or try to).

This is why you want VE to be properly tuned/corrected.

Understood. Thank you SO much!

[Boost]

19087

Yup...