Full line pressure with A4 SD tune

[jnorris]

A few nights ago I flashed in a SD tuning file using EFILive/AutoVE Tuning guide in my 98 Z28 with an A4 transmission and have a problem.

The PCM is commanding full transmission line pressure at all times. All shifts are very harsh. I checked the transmission DTC fault enablers for P0101, P0102, and P0103 and they are set to “No”
The Engine DTC MIL Enablers for these codes are set to “No MIL” per the EFILive/AutoVE Tuning guide.
What can I do to prevent the PCM from commanding full transmission line pressure on all but heavy/full throttle shifts?

Thanks

John

[joecar]

Disable P0101, P0102, P0103 in the following table: E0102 (Trans. DTC Max Pressure Enablers).

[jnorris]

Disable P0101, P0102, P0103 in the following table: E0102 (Trans. DTC Max Pressure Enablers).

I checked that and they were all already set to "NO". What is strange is that I thought these were set as "YES" in the stock tune. I never changed them to "NO"


John

[Black02SS]

I would like to know this as well as I have experienced this on a few cars.

[Black02SS]

Ross or Paul.........Any update or suggestions?

[GMPX]

No further suggestions, I thought that would cure it which is why we put that table in, I'll look into what else may cause it.

Cheers,
Ross

[Black02SS]

Oh. Keep us updated if you find anything else.

[GMPX]

Just a thought, log PID 'GM.TSTATE07' and look to see if the PCM is flaging full line pressure due to a DTC being set.

Cheers,
Ross

[jnorris]

Just a thought, log PID 'GM.TSTATE07' and look to see if the PCM is flaging full line pressure due to a DTC being set.

Cheers,
Ross

Done.

Below are the codes with the SD tune in the PCM and the MAF unhooked. At idle the trans pressure was 30psi in neutral and 35 psi in drive.
P0102 "Mass Air Flow (MAF) Sensor Circuit Low" EPA Pending ($10) "Powertrain Control Module (PCM)"
P0102 "Mass Air Flow (MAF) Sensor Circuit Low" PC ($10) "Powertrain Control Module (PCM)"


Below are the codes with the SD tune in the PCM and the MAF hooked up. At idle the trans pressure was 30psi in neutral and 35 psi in drive.
P0102 "Mass Air Flow (MAF) Sensor Circuit Low" EPA Pending ($10) "Powertrain Control Module (PCM)"
P0103 "Mass Air Flow (MAF) Sensor Circuit High" EPA Pending ($10) "Powertrain Control Module (PCM)"
P0103 "Mass Air Flow (MAF) Sensor Circuit High" PC ($10) "Powertrain Control Module (PCM)"

With the MAF tune in the PCM the trans pressure was at zero psi in neutral and 5psi in drive.
Maximum pressure due to MALF (TSTATE08-MAXPRES) was at “NO” during all tests.

John

[joecar]

30/35 psi is not max line pressure, but is somewhat high for idle (expected is 5-10 psi).

It seems as if the PCM is modifying line pressure based on airflow... BUT there appears to be no table for this.