Need help with a P0068 code

[chpspecial]

Hello everyone, I have a problem with a truck that i am tuning. It is a 2004 Silverado SS with a 11:1 compression 408, cam and heads as well as a Kenne Bell 3.4 supercharger. the supercharger is making 10# of boost, but every time it hits about 6# and ~4800 rpm, I get a P0068 code.

The truck also has a nick williams 102mm TB, with the speartech harness, and tac module from an 02 suburban... Any one have any insight.

Thanks All
Reynaldo

[ScarabEpic22]

Thats a MAP/MAF offset error, you need to adjust the TPS vs airflow tables. Plug your FS into your computer, then open the tune file. Should be under either Engine->ETC or Engine Diagnostics->ETC. Look for Electronic Throttle Control, there are between 2-5 tables that need to be adjusted. Why are you mixing 99-02 parts and 03+ parts? Id ditch ANYTHING not related to 04, get a regular 04 TAC module. IMHO, thats asking for a lot of unnecessary issues.

[chpspecial]

Thanks for the reply, I am aware of the description of the P0068 code. I am looking for more insight on it. The reason for the 02 parts is because that is one of only two ways to control a car style TB on a gmt 800 truck. We are unfortunate to only get the 8 pin 78mm TB and if we want to run the bigger car style, there are two ways of doing it, 1. we get the Dr. X, x link. This harness converts the signals from OE wiring 8 pin harness to the car style (ls2/3/7/9) 6 pin harness, or 2. we get the TAC module from an earlier vehicle such as a 02 suburban with ETC and the speartech adapter harness. Or keep the 78mm TB and bottleneck a nice supercharger. I have already maxed out and turned off the MAP MAF diagnostics, as well as the codes and no luck.

I have also switched out MAP sensors and the Nick Williams 102mm for a LS2 90mm, and the next step is the TAC module and harness, for a 2004 TAC and Dr. X harness.

Thanks all for looking

[izaks]

C0803
c0805
c0806

[chpspecial]

C0803, C0805, and C0806 are not available in cos 04073003

sent from my thunderbolt

[izaks]

Sorry,
C2911
C3003
C6101
C6102

[chpspecial]

Thank you for the reply, all those tables have been maxed out and I still only get the p0068 code... Next step is the tac module

sent from my thunderbolt

[chpspecial]

UPDATE, I swapped TAC modules with a dr.X harness and still have the same P0068 code. However, I re enabled the MAF, and all is well... Fueling is all out of wack but no more p0068 code. SO... maybe its a bad PCM that doesn't like been in SD mode.

[wait4me]

Did you try just deleting that code?

If the pcm uses maf sensor it is using an actual airflow based input.
When using a Speed density program instead, it is using Ve, rpm, IAT, tps, map, and a few other things to show what it is taking in for airflow.

Sometimes, you can multiply your fueling tables and ve tables DOWN by a percentage to bring the values back in line. There are other ways as well, but that is the most simple solution.

When you max out those other values, and set the temp enablers and other things to not hit, then it should go away, or the simple thing is just turn off the code. X.