Notices
GM Engine & Exhaust Performance EFI | GEN I/GEN II/GEN III/GEN IV Engines |Small Block | Big Block |
Sponsored by:
Sponsored by:

TPS codes (P0121?)

Thread Tools
 
Search this Thread
 
Old 06-29-2004, 07:10 AM
  #1  
MOOBIES Moderator
Thread Starter
iTrader: (6)
 
Scream's Avatar
 
Join Date: Apr 2002
Location: Jacksonville, FL
Posts: 4,924
Likes: 0
Received 1 Like on 1 Post
Default TPS codes (P0121?)

I have had a recurring problem ever since I put the cam in the 4.8, and it's carried over to the LS1 even though I changed throttlebodies AND TPS sensors.

I keep getting a TPS (I think is P0121), mainly at idle. Sometimes, it will go away. Other times, it will stay on forever. I've also gotten a MAP sensor code off and on as well.

Now, I haven't replaced the TPS with a BRAND NEW one--a buddy had an extra TB laying around so I snatched the sensor off of that. Should I try a brand new GM sensor first, or is there something else that could be causing the problem? Any ideas at all? Can this be tuned out w/ EDIT?

It doesn't seem to affect the performance of the truck, but damn it's getting on my nerves.
Old 06-29-2004, 12:22 PM
  #2  
MOOBIES Moderator
Thread Starter
iTrader: (6)
 
Scream's Avatar
 
Join Date: Apr 2002
Location: Jacksonville, FL
Posts: 4,924
Likes: 0
Received 1 Like on 1 Post
Default

Anyone?
Old 06-29-2004, 12:36 PM
  #3  
9 Second Club/LS1TECH Sponsor
iTrader: (14)
 
Speartech's Avatar
 
Join Date: Nov 2001
Location: Anderson, Indiana
Posts: 1,661
Likes: 0
Received 0 Likes on 0 Posts
Default

That code is actually looking at the relationship between the MAP sensor and the TPS. When the PCM sees a TPS angle that doesn't match an expected MAP range, the code sets.
I think the problem is not with the TPS, but with the MAP sensor. I would look at the wiring to the MAP sensor or maybe try another one. I think you ruled out the TPS when you tried another throttle body.

The problem has to exist for 15 seconds for the code to set, so if you could get a scan tool on there you might see where the problem is.

You can turn it off with Edit but I wouldn't advise it; I think you would be covering up a problem that way.
Old 06-29-2004, 12:43 PM
  #4  
MOOBIES Moderator
Thread Starter
iTrader: (6)
 
Scream's Avatar
 
Join Date: Apr 2002
Location: Jacksonville, FL
Posts: 4,924
Likes: 0
Received 1 Like on 1 Post
Default

Okay, I'll try that. Thanks John!

BTW--I didn't get any instructions w/ my 4L80E conversion harness. I saw that the wires are marked, but that doesn't mean much to me. Can you (or anyone) hook a brother up?
Old 06-29-2004, 01:01 PM
  #5  
9 Second Club/LS1TECH Sponsor
iTrader: (14)
 
Speartech's Avatar
 
Join Date: Nov 2001
Location: Anderson, Indiana
Posts: 1,661
Likes: 0
Received 0 Likes on 0 Posts
Default

Yeah, there aren't any instructions with it. Since the 4L80E adds the ISS (input speed sensor) you have to route those 2 wires up to the PCM.
Unhook the connectors from the PCM, pop the gray cover off of the back so that you can see the position numbers, pop the RED cover off by pushing in on the latches on each end, and insert the 2 terminated wires into the proper position (21 & 22). Reverse the procedure and you're ready to go.

The other part is just a direct plug in between the old 4L60E harness and the 4L80E transmission.
Old 06-29-2004, 01:26 PM
  #6  
MOOBIES Moderator
Thread Starter
iTrader: (6)
 
Scream's Avatar
 
Join Date: Apr 2002
Location: Jacksonville, FL
Posts: 4,924
Likes: 0
Received 1 Like on 1 Post
Default

thanks John! Are the slots on the PCM marked, or do I need a diagram?
Old 06-29-2004, 01:36 PM
  #7  
9 Second Club/LS1TECH Sponsor
iTrader: (14)
 
Speartech's Avatar
 
Join Date: Nov 2001
Location: Anderson, Indiana
Posts: 1,661
Likes: 0
Received 0 Likes on 0 Posts
Default

Once you pop the long gray cover off of the back, you can see all of the numbers above each terminal hole.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Pimpinpete
GM Engine & Exhaust Performance
43
12-22-2017 08:13 AM
00loudchevy
Tuning, Diagnostics, Electronics, and Wiring
3
12-03-2015 05:54 PM
Avalanche2002
Tuning, Diagnostics, Electronics, and Wiring
7
11-30-2015 07:31 AM
bearden86
GM Engine & Exhaust Performance
26
11-15-2015 03:58 PM
Pimpinpete
GM Engine & Exhaust Performance
3
09-08-2015 07:39 PM



Quick Reply: TPS codes (P0121?)



All times are GMT -5. The time now is 08:06 AM.