PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

A little DTC help for a LS1 noob

Old Mar 15, 2011 | 11:10 PM
  #1  
s porter's Avatar
Thread Starter
Teching In
iTrader: (2)
 
Joined: Feb 2011
Posts: 3
Likes: 0
Default A little DTC help for a LS1 noob

First of all, lovin' this site...Although, all the information can be a little overwhelming at times Anyways, I'm in the midst of a 87' Buick T-Type LS swap. Have a 5.3 sitting in the car now with a modified 2000 truck harness and computer minus a few accessories along with the MAF. Fired the car for the first time the other night and it hit instantly. Ran it for about 15 mins at idle and couldn't of asked for anything more from it....My buddy that's been helping me some on the project, reached down and blipped the throttle and the car died. Have been unable to get the car to idle since. Turn the key, the car hits and immediately dies...Almost like a VATS issue, but I have that disabled in the HPTuner software. Here's 4 of the 5 codes that the scanner shows:

[PCM] P0122 - Throttle Position (TP) Sensor Circuit Low Voltage (Pending) (Immature)

[PCM] P0452 - Fuel Tank Pressure Sensor Circuit Low Voltage (Pending) (Old) (Current) (Immature)

PCM] P1122 - Throttle Position (TP) Sensor Circuit Intermittent Low Voltage (Pending) (History) (Immature)

[PCM] P1635 - 5 Volt Reference Circuit (Pending) (Current) (Immature)

[PCM] P1639 - 5 Volt Reference 2 Circuit (Pending) (Current) (Immature)

From what research I've done, I believe the Fuel Tank Pressure Sensor and TPS are both tied to the same 5V circuit. My question is, since I am not running a Fuel Tank Pressure Sensor, could this be causing the TPS and 5V reference issues I'm seeing??? If so, how do I go about correcting it? Any help appreciated as I'm new to the LS world. Trying to work out the bugs on this engine before I drop the built 6.0 in it. Thx Scott
Reply
Old Oct 26, 2011 | 04:37 PM
  #2  
maxgee's Avatar
TECH Fanatic
iTrader: (5)
 
Joined: Dec 2007
Posts: 1,458
Likes: 5
From: Canton, Ga
Default

You ever figure out the issue?
Reply
Old Jun 1, 2012 | 04:02 PM
  #3  
luigiandme's Avatar
Launching!
iTrader: (2)
 
Joined: Jun 2008
Posts: 288
Likes: 1
Default

Sorry to bump this thread after a years. This is only for people looking to figure out this issue. Try checking your wiring harness behind the ECM. A smaller group of wires in black conduit will be coming out of the firewall on the passenger side. Remove the ECU to gain access. There's a self tapping screw that this harness may have rubbed through. Open the conduit and repair wires if necessary and secure harness away from screw!
Reply
Old Jun 1, 2012 | 05:33 PM
  #4  
Old Geezer's Avatar
TECH Senior Member
iTrader: (3)
 
Joined: Jun 2004
Posts: 5,639
Likes: 71
From: GA, USA
Default

Huh?? This is a swap. What leads you to think the pcm is in a location that will cause what you are describing??
Reply


Thread Tools
Search this Thread

All times are GMT -5. The time now is 01:49 PM.

story-0
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-1
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-2
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-3
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-4
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-5
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-6
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-7
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE
story-8
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0

The world was a better place when it was still around.

By Brett Foote | 2026-01-23 09:20:37


VIEW MORE
story-9
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever

Slideshow: The 7.0-liter LS7 was designed for absolute cutting-edge performance.

By Verdad Gallardo | 2026-01-07 18:36:00


VIEW MORE