Gilbert Correa

Thanks for the direction to look in. I had started to tear out all of the carpet to follow the wiring harness to see if there were any abraded areas that might have caused the battery to drain, but found none. What a way to get me to clean the carpet... Everything looks clean (should have taken a picture of how clean and rust free the metal under the carpet is) and the wiring looks fine. I saw various connectors that went to the seat and aft to the rear window defogger, but everything is clean and dry. Connectors tight and wiring to the pins tight. I had put a charger on the battery over night and had the battery light come on when I was checking the codes (3500 was one that I didn't find out yet) but had nothing that would point me in the direction for finding the root of all these crazy problems. The battery light and message turned off the second time I started the truck up, and I haven't had a problem since. The gauge reads a steady 14 with minor fluctuations when reving the motor, and all other gauges are nominal. For the last few days I haven't had the problem, but I don't know if I solved it when I disturbed the wiring harness. I've put about a hundred miles so far since the last episode, and no re-occurrence. The only thing that shows occasionally is the front drivers abs sensor, but i think that's totally unrelated to the problem I have had with the Accelerator Pedal Sensor issue. I just think I need a new sensor for that wheel...
Oh yeah, I bought a code reader as I couldn't keep asking my buddy for his, so now I can read codes as they happen. I'm still getting use to using it as there are a lot of "front end programs" to choose from, and just finding the one that will give me the best performance and display is time consuming.

usp45

I have been having the same problem with my 03 4.8 silverado. I took it to the shop and they said they cleaned the t-body, and if it happened again I would need a new t-body. Its started happening again about 3 months later and Ive been dealing with it by pulling over. Im gonna stop and get my codes from autozone today. My truck has 226000 miles and runs awesome aside from this, but it does feel less powerful from 123000 when i got it.

suburbancrazy

I have a 2003 Chevy Suburban with 5.3L with adjustable accelerator pedals.
It has 220000 miles. At 200000 miles I started getting intermittent Reduced Engine Power message usually after recranking car about an hour after a long drive (30 minutes or more). Lately the Reduced Engine message is happening more frequently and is a nuisance. I took it to Autozone and their reader gave P2138 for Accelerator Pedal Position sensor. So I bought one and think I need to replace it.
Questions.
1. Can anyone tell me how they replaced it. I cannot access one the screws that hold it to the accelerator assembly. I read in this thread that there is a knee bolster that has to removed first. What is that? Can anyone tell me the correct way to remove the accelerator assembly. I cannot reach the upper bolt that connects it to the firewall.
2. DO you think the Throttle body needs cleaning instead?

Please provide any guidance. My truck runs great other than this problem!

suburbancrazy

What is the knee bolster? I am cannot figure out how to remove the accelerator assembly. The upper bolt that holds it to the firewall is completely inaccessible.
Any suggestions? I need to replace the accelerator pedal position sensor.

suburbancrazy

Gilbert,
How did you replace the accelerator sensor? I cannot access one of the sensor screws or the upper bolt to remove the accelerator assembly.
Did you ever fix the Reduced engine power errors?

nhien

Yes, my Captiva 2008 got same problem for 6 months ago. I had replaced new accelerator pedal but it just got fine for about 100km couple of days. then get trouble codes p2121 and p2138
Opening the high bolt is very hard. but now i can open easily by common curved wrench of 10 mm. do it likely blind person, you should do not try to see it. just use finger feeling...

nhien

I checked many things, cleaned t body, check ecm harness, pedal harness, every look good, I also measured voltages at pedal harness pin holes by common

electric multitest tool, they are right, but still could not found the bug. I can reprocedued the DTC p2121 and p2138 by turn on the key but not start, then press and depress pedal many time slowly and fast. After I install new pedal, I did likely that and no DTC comming, running very well after that. I thought bug gone, but now it come. So sad....

nhien

just cover a haft made sure water go to two side and dropped. This is second hand car so i dont know if its wire opened by repairing or not, so it may be get weak water ressistant

nhien

DTCs p2121 and p2138 still came after pedal replacement and clearing DTCs for about a week and 300km. ecm also report few more DTCs related throttle body as p2107, p2176 and even checkengine light but no DTC found, one time the alert sounds get very bigger but all of them gone after a night when I clear DTCs by ODBii tool.
I doubt again the electric system may be get water intrusion some where, but there is not rain here.
Then i double Airconditioner water might produce the water. I opened the engine room cover and see how water from AC hose dropped down to electric wire and harness below.
IT showed so much water randomly dropped down.
So finnally i did water treament for AC hose by common AC water treatment stuffs.

So happy , look like this works. the car get no DTC for over 500km in 3 weeks of run. The intermittent bug seemly was fixed, but i continue observe it and report later.

nhien

Finally i found 3 serious water intrusion sites in gutter design of captiva. Doing water treatment my self then all DTCs gone. the blue site made Throtte body and cylinder sensors fault voltage, red and green made accelerator and orther electric issue. I belive that is wrong design of gutter for Captiva. I check few Toyota cars and Chevy colorado gutters, all of them are good but Captiva.
Who search google and found this page, can contact me for detail of water intrusion treatment touch me email to nhien@nhien.net or thuatnhien@gmail.com