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2002 chevy trailblazer_ls
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Discussion Starter · #1 ·
i had this problem for about year,its sux,first it started with my first engine(swapped engines blew rod)got code p1271,put new engine in still same problem,changed fan clutch today with harness,still p1271.I noticed the REP comes on when i barely press the gas,if i press more then 20% on throttle,REP doesn't come on.What can i do to see about this problem?Two different engines with the same problem?i think its within my electrical system somewhere.Oh yea the codes i get is p1271,and some times p1270( Accelerator Pedal Position Sensor A/D Converter Error)p1275(Accelerator Pedal Position (APP) Sensor 1 Circuit) & p1280( Accelerator Pedal Position (APP) Sensor 2 Circuit)Plz if any one could help me out!!PLUS some times on a cold start the REP is already on with out me pressing the throttle and it won't accelerate,and YES i changed the pedel twice.PLZ any help
 

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2004 gmc
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Sure sounds like an intermittent open or short in the wiring between the PCM and the APP. Have you examined the wiring very carefully, especially in the area of the firewall grommet? Put a meter on the APP sensor wires to see what the voltage actually is that the PCM measures?

The APP depends on a good reference voltage and ground for each of the two redundant sensors, plus the position sensor output signals need to get back to the PCM to be measured. Interference anywhere along those paths could give you REP.

Same PCM on the new engine as the old?

Try pulling the fan clutch harness totally off, to prove that isn't it.

Any background on how the rod blew, or was it a mystery failure?
 

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Discussion Starter · #3 ·
Sorry for the delay i was in LA =).Yes it is the same PCM and i checked the fan clutch harness from the wiring and it looks fine i can post pics.As for the APP senser,that is located under the dash?the pedel right?And i need a DVM to test it right?A nd where would i test it?This problem is getting worse by the day,but i can't give up.THX FOR THE REPLYS
 

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Discussion Starter · #5 ·
Just in case anyone is interested,i found the prob.It is the harness connector connected to the Accelerator Pedal Position Sensor.I found this out by turning on the ignition and wiggling the purple wire,the REP light comes on WHILE engine is off,pulled the code,p1271,thats IT!!!Now gotta find that part,dealer doesn't carry that part,they sell the whole harness for $1200!!Any one got any ideas?
 

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2004 gmc
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The dealer should certainly have the connector housing, perhaps in the drawers of parts the techs have access to.

Anyway, I'm not certain of the EXACT connector, but in the shop manual it looks like this:



I find listings where you can buy the connector (with pins or pigtails I don't know) for $70 or so.

PT1558 88988944

Jackpot!

$60 with pigtails:
http://www.rmsautoparts.com/proddetail.php?prod=PT1558

D16 PT1558 - Accelerator Pedal Position Sensor Connector
INLINE-TO F/TNK HARN CONNECTOR
6-WAY FEMALE BLACK
Cross Reference for GM Part Number: 88988944
Supersedes GM Part Number 88953153

List Price: $103.18
Price: $59.00

 

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Discussion Starter · #7 ·
Thanx for the source,i could of sworn it had 8-10 connections(4 on each sidei think)ill check it out tomorrow,hope this helps others with the same problem.
 

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Discussion Starter · #9 ·
just an update*went to radio shack and bought some connector cleaner,sprayed some one on both connector/app sensor,and DAMN it rides sooo much better,i can press the gas again:hail:BUT as i was driving,i was play some tool(sober)with the bass all the way up and the light came back,maybe i need a stronger battery
 

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Discussion Starter · #10 ·
Hey roadie,you wouldn't happen to have more links about the Accelerator Pedal Position Sensor Connector would you?i need to fix this small problem :)
 

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Discussion Starter · #14 · (Edited)
Solved

thread revived....i fixed the problem awhile back,i forgot about this post but if there is anyone with the same problem maybe this would help....
i just went to GM and got the OEM pedal for $125.00 and the problem was fixed,a mechanic told me to buy the OEM pedal instead of going on rockauto.com and getting universal ones,so i followed his advise and he was rite,since oct. no problems,i hope this helps any one with this problem out there
 

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2003 gmc envoy_slt_xl
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Was the problem the connector?

I have been having the same problem with my 2003 envoy. I put in a new battery and after driving 2 miles the reduce power to engine light came onand the fuel gauge went out of wack and the power reduced to about 5-10 mph. The codes said p1275 and p1280. I put in a new app pedal but still the same issue. *Looks like i was going the same route image was. But correct me if I am wrong but was the issue the connector and not a new app pedal? *Was it fixed after you put it in and was the damage to the wire visible? thanks. This have been driving me crazy.*
 

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All your other symptoms sound like a bad APP or at least the connector/wiring
*except* for the fuel gauge going out of whack. It could be unrelated, but
you might want to check your ground connections.

One other thing to consider is that the APP shares the 5V reference with
the fan clutch. Check that harness for damage as well.

Just a thought....

Good Luck!

Chris
 

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Discussion Starter · #18 ·
All your other symptoms sound like a bad APP or at least the connector/wiring
*except* for the fuel gauge going out of whack. It could be unrelated, but
you might want to check your ground connections.

One other thing to consider is that the APP shares the 5V reference with
the fan clutch. Check that harness for damage as well.

Just a thought....

Good Luck!

Chris
i had heard about that connector having issues too,about the APP u got,i bought 2 of those before and the problem still didnt go away, check what Chris is talking about and/or get OEM APP. Best of luck
 

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How do you check that.

Thanks Chris I will check the fan. I put in a new app pedal I bought from dorman to same 80 bucks but am not certain on the part I m not certain if the oem part is the same or better. In regards to checking the ground. How do you do that? * Thanks for your help. I'm trying to avoid taking it in but we shall see.
 
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