Main VE vs Backup VE in 97/98 PCM's

[TurboCamaro]

What drives the PCM to select the Main or the Backup VE table iin 97 & 98 PCM's?

[joecar]

When a MAF DTC is current, the PCM selects the Backup VE table.

[ i.e. P0101, P0102, P0103 ]

[TurboCamaro]

Makes sense now.
I typically set a MIL when doing VE so that I confirm the MAF has failed.
Thanks Joe.