2005 gto 6.0 / 4l60e

[joecar]

When you unplug the MAF, then either of the following will happen:
- if the trans fault max pressure table has MAF DTC's enabled, then commanded pressure goes to max (PC current drops to zero);
- if the trans fault max pressure table has MAF DTC's disabled, then commanded pressure is calculated from torque model which is calculated from VE table (PC current drops as load increases).

so if you unplug the MAF and you see either of those then the MAF and/or the MAF table has a problem;

( if the MAF does not respond appropriately to throttle opening, then the calculated torque will be low which causes the commanded pressure to be low (PCS current will be too high )

if the MAF table looks like a rising exponential curve then look closely at the MAF it may be faulty/failed, log MAFFREQ, MAF, DYNAIR.

[joecar]

To me, the MAF tables look a little low... at 10kHz I would have expected more than 300 g/s airflow.


However, that still does not explain 0.51 g/s during the road test, I would have expected 50-150 g/s for driving around on surface streets, and 270-300 g/s for WOT.

[joecar]

Erik has a good point about the MAF Error patch B9901, apply it and see what MAF reads.

[02CCSB]

Hmmm, so then could I intentionally make it reference the VE table instead of the MAF by disabling the DTCs?

[joecar]

Arghhh... the T42 file does not have a fault max pressure table.

[02CCSB]

Ok, so I'll try that MAF patch first, then a new MAF, if neither work then I'll do the vac mod. No biggie.

[joecar]

First, apply the MAF patch, log the MAF, and see what PCS current does... let's just see where we stand with that.

[joecar]

And also, unplug the MAF, make sure a MAF DTC triggers, and see what PCS current does.

[joecar]

Hmmm, so then could I intentionally make it reference the VE table instead of the MAF by disabling the DTCs?

When a MAF DTC triggers, the ECM ignores the MAF and uses VE exclusively...


i.e. the calculation chain goes something like this:

VE -> airmass + spark advance -> torque -> trans pressure

[02CCSB]

Will advise