TPS Fault codes and cams [Archive]

GMPX

January 19th, 2005, 04:15 PM

WOW, the first how to and the winner is a simple DTC fix.

O.K, so anyone who has fitted a cam knows the dredded TPS fault code that comes up (usually P0121 at idle with the A/C going).

Instead of simply turning off the fault code in the DTC enabler section, all that needs doing is to 'expand' the range the PCM thinks is a valid Throttle Position.

Look at table - C3907
It's pretty simple how it works.

For a given RPM the PCM expects the TPS to be above a certain percentage. Looking at the attached screen shot...

At 400 RPM, the PCM expects the TPS to be at 0%.
At 800 RPM, the PCM expects the TPS to be at 1% or higher.
At 1200RPM, the PCM expects the TPS to be at 5.3% or higher and so on.

Now, throw a camshaft in that needs to idle at 850, 950RPM and the PCM is still going to expect the TPS to be at 1% or higher.....not the case with your new cammed motor.
So, just simply identify your idle speed range, and change the values to 0 so the PCM will now accept the throttle is allowed to be closed at 950RPM.

http://www.efilive.com/upload/public/GMPX/TPS.png

bink

January 20th, 2005, 01:00 AM

GMPX Hi!
I was curious why mine never set. Checked my orig file - 0121 is turned off from ht e factory. Starndard for ETC??
Cheers,
joel

GMPX

January 20th, 2005, 01:21 AM

GMPX Hi!
I was curious why mine never set. Checked my orig file - 0121 is turned off from ht e factory. Starndard for ETC??
Cheers,
joel

What year is your car?
I just checked some 2000 and 2001 C5 files and they both have that DTC test enabled. Maybe Chevy knew what was going to happen to your car.

Cheers,
Ross

jfpilla

January 20th, 2005, 04:35 AM

GMPX Hi!
I was curious why mine never set. Checked my orig file - 0121 is turned off from ht e factory. Starndard for ETC??
Cheers,
joel

What year is your car?
I just checked some 2000 and 2001 C5 files and they both have that DTC test enabled. Maybe Chevy knew what was going to happen to your car.

Cheers,
Ross

Mines an 03' and it's also off?

bink

January 20th, 2005, 07:25 AM

What year is your car?
I just checked some 2000 and 2001 C5 files and they both have that DTC test enabled. Maybe Chevy knew what was going to happen to your car.

Cheers,
Ross

My car is a 2001. I think it's special.

What do you mean maybe Chevy knew what was going to happen to my car?!!

Where is the "Face hurts laughing " emoticon??

bink

January 20th, 2005, 08:09 AM

What year is your car?
I just checked some 2000 and 2001 C5 files and they both have that DTC test enabled. Maybe Chevy knew what was going to happen to your car.

Cheers,
Ross

My car is a 2001. I think it's special.

What do you mean maybe Chevy knew what was going to happen to my car?!!

Where is the "Face hurts laughing " emoticon??

GMPX

January 20th, 2005, 09:21 AM

Do all you guys have Z06's?, I just looked at a stock Z06 file and it is turned off.

Bink, I just meant, you would be messing with the car at some stage so Chevy saved you the trouble.

Cheers,
Ross

bink

January 20th, 2005, 10:17 AM

Mine's a Z06.

Bink, I just meant, you would be messing with the car at some stage so Chevy saved you the trouble.

Yeah, I knew..... just a retort. Your comment was why I was looking for the "Face Hurting Laughing" emoticon.

jfpilla

January 20th, 2005, 11:12 AM

Mine's a Z06.

Bink, I just meant, you would be messing with the car at some stage so Chevy saved you the trouble.

Yeah, I knew..... just a retort. Your comment was why I was looking for the "Face Hurting Laughing" emoticon.

Joel,
Did you get my mail?
Your just too subtle. :lol: