2003 Tahoe 4x4 5.3 flex fuel. Bought it about 5 months ago and the PO had replaced the throttle body with an AC Delco one because of a reduced power mode. I see a new pigtail on it as well. It apparently fixed it. I bought it (maybe foolishly!!) and drive it for 2 months with it running perfect. But then it went into reduced power mode several times over the course of a couple weeks with codes P1516 and P2135. I noticed the TAC had a Dorman sticker on it so I replaced it with a factory one from the junkyard. It seemed to fix the problem and I drove it for another 2 months with zero problems. I thought I was in the clear. But tonight the reduced power came back with a pending P2135 code. Not sure where to go from here. The accelerator pedal doesn't look nearly as worn as the brake pedal and I'm wondering if the PO replaced that as well, but I'm not sure. Any help is greatly appreciated!
P2135 - please help!
- Thread starter 9C1C
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The link below will take you to the CHARM site for the diagnostic procedure for that code. Verify the vehicle, though, and navigate to yours if needed.
P2135 — 2003 Chevrolet K Tahoe 4WD V8-5.3L VIN Z Flex Fuel Service Manual | Operation CHARM
Detailed repair manual for the 2003 Chevrolet K Tahoe 4WD V8-5.3L VIN Z Flex Fuel.
charm.li
Thanks, I don't have a scanner but will run through what I can. Curiously, there's no solution at the bottom that recommends the accelerator pedal sensor to be replaced. Is that out of scope for this code?
Wish it wasn't hard to convert drive by wire to drive by cable, as I'd do that in a heartbeat!
Wish it wasn't hard to convert drive by wire to drive by cable, as I'd do that in a heartbeat!
Really need a scanner to watch the values.
I've never dealt with this issue, but I would very carefully inspect each wire from the throttle body connection, as well as the connections and wires at the TAC. As a SWAG I'd also pull both PCM connectors and inspect for water intrusion and connection issues.
I know that @rockola1971 has commented about these issues in the past, maybe he has a suggestion or two.
I've never dealt with this issue, but I would very carefully inspect each wire from the throttle body connection, as well as the connections and wires at the TAC. As a SWAG I'd also pull both PCM connectors and inspect for water intrusion and connection issues.
I know that @rockola1971 has commented about these issues in the past, maybe he has a suggestion or two.
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When u replaced the parts, did u disconnect the battery and or do a relearn? Sounds like the sensors are out of correlation. Specs are real tight. Also when u clean the yard replacement throttle body, u CANNOT push the throttle blade wide open by hand. U can close it but not push it wide open.
I didn't disconnect or do a relearn after putting in the used/oem TAC. Everything ran perfect for a couple months so I thought I was good. I'll try disconnecting the battery.
rockola1971
Full Access Member
So the most common failures are listed in order of most common:
1: Broken wire(s) in Throttle Body TPS Harness. Usually a broken wire approximately 6" away from plug. The insulation is NOT broken.
2: Worn TPS. Has a dead spot where you typical hang out (speed) the most. City 30MPH or Highway 55MPH or so.
3: Wire Harness at TAC Module. Wire will break right at the plug. The insulation will NOT be broken.
4: Bad Tac Module
5: Bad Accelerator Pot assembly at the throttle
Very high mileage vehicles then it could be any one of the above.
When replacing wire harness cut back as much of the old harness by as much of the new pigtail will allow since most failures happen around the 6"+ from the plug in the case of the TPS.
Many of the above failures are very hard to diagnose since you have to be in gear and moving to catch which makes it very difficult to check for missing voltages in a flash of a second or so.
rockola1971
Full Access Member
#5 is throttle pedal assembly (it is all sold as a unit).
#2 is the TPS and is bolted on to the throttle body. Factory original is riveted on and you must drill out rivets to replace.
Honestly I would replace the TPS before I would consider the throttle pot, especially if the TPS is riveted on which means it is original. The TPS is alot cheaper too.
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Idle air?
Update: checked everything that I could. I still had the codes. I replaced the pedal and sensor with a good one from the junkyard, and got a used OEM throttle body as well. Ran great for a month, now P2135 is back. How can I tell if the wires at the TAC plug are not broken (insulation is good)? Any tips on how to check the wiring? I'm at my wit's end.
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If I walked up to u and ur truck and put my scanner on and asked the truck to do a idle reset or a throttle relearn, which if I remember should happen while the key is on and engine off. It'll ask u to put throttle to floor and hold and or release. Around them lines. In the fuel data on a scanner with it running u should see throttle percentage. Take a deep breath. You will get it.
