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brunson67 · 07-12-2022, 05:22 PM

Hi all,

As I got ready for our River trip for my wife's 50th bday, I pulled the RV out from the side of the house and it immediately went into a limp mode/reduced engine power mode. My neighbor came over with his scanner and it showed a P2138 code, Throttle/Pedal Position Sensor/Switch "D" circuit, and P2138 code, Throttle/Pedal Position Sensor/Switch "D"/"E" Voltage correlation. He ran a diagnostic and it showed the actual throttle pedal was working, showing I believe ohms? from 0-100%. As we were messing with it, it suddenly cleared itself. Luckily we got to our destination and home without an issue. But it now has done it a few times just when I start it periodically to let the engine warm up and cycle. I can do a ECM reset and it clears the reduced power code, but he check engine light stays on. My Mechanic said its typically the throttle body on the 8.1. As of just a few months back I did new plugs, air filter, plug wires, cleaned the throttle body, and cleaned the MAF. It does have an Ultra RV reprogrammed ECM, its been installed for about 1 1/2 years. Any thoughts?

HarryStone · 07-12-2022, 06:01 PM

2138 is a code that indicates a mismatch between the throttle pedal and the throttle position sensor on the throttle body. If the pedal sensor is indicating right, then it's gotta be the throttle position sensor, or wiring between.

brunson67 · 07-13-2022, 09:00 AM

Thanks HarryStone! Should I just start be replacing the throttle position sensor to see if that fixes it? Is it an easy replacement?

rollinj · 07-24-2022, 12:12 AM

Get a Delco throttle body from autozone or Amazon! I just did mine. You will need to really smash on it to fit it in at just the perfect angle. Coolant line in the way. The stud needs to bend a bit to get er in.

Get a new sintered metal gasket & have a razor ready to clean up intake side.

Cheap & easy. Keep in mind the pigtails & wires known to fail on gm of this vintage. Do a wiggle test while running at throttle body first.

I did throttle body, pedal & the computer that controls it all. Blew $1000 for peace of mind. I've git little kids & broke down in front yard day I got home from 1500 mile roadtrip!

Your foot also kicks the wiring to the computer mounted to steering column & connector sucks. Gives similar codes if not PERFECTLY tight.

12679526 is the 2003 w22 part number.

brunson67 · 07-25-2022, 09:02 AM

Thanks rollinj, all great tips and advice! And yes, I have kids, so dad cant let the family down, need to get us there and home! LOL

rollinj · 08-19-2022, 10:22 PM

My advice wasn't that great! I'm now broken down in the boonies.

Codes p0220 p2135 p1516.

I've got a new throttle computer, new gas pedal & new Delco throttle body.

600 miles since replaced and now it's left me stranded again!

Hope I have info to share on repairs soon.