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Reduced Engine Power Message

firefighteremt3100

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Eljefe8669 New Member

Eljefe8669

Posted
Posted

I buy around 100 chevy trucks a year so I am very familiar with this issue.

 

99% of the time the reduced engine power is due to the gas pedal. I always replace that first.

 

Second is wiring going to the TB itself. Dorman makes a kit with a new harness and TB motor. I have never seen the motor fail but I have found two bad harness connections.

The third is the TAC Module on the firewall driver side. I have only seen a TACs Module fail once.

 

Replace the gas pedal and im sure all will be fine.

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Eljefe8669 New Member

Eljefe8669

Posted
Posted

I have replaced the throttle body and none of the wires appear to be loose but I do have a new harness. So the next step could be the gas pedal sensor correct?

  • 1 year later...
Jason Knorr New Member

Jason Knorr

Posted
Posted

My 2007 Silverado went into Reduced Engine Power a couple weeks ago. It threw several codes relating to the TPS, throttle body and APP sensor. I've replaced the engine ground strap (as I've read this might be the cause), the TPS and wire connectors, cleaned the TPS ground connection on the engine block and replaced the throttle body. None of these have fixed it yet. I'm putting a new APP sensor on tonight. I'm hoping that works otherwise I have no idea what it could be. GM has a technical bulletin that says it can be caused by leaking water getting the APP sensor wires wet or by aftermarket equipment being wired in. I don't have any aftermarket equipment or a leak that I know of, but I'm going to check the APP wire connections too.

After replacing parts, the check engine light would not be on. I found that by tapping the accelerator pedal three times, the check engine light and the Reduced Engine Power message will come back on. So you might want to try that to verify it's fixed after replacing parts. Otherwise I've heard that this issue is intermittent and sometimes goes months before it occurs again.

  • 2 weeks later...
Jason Knorr New Member

Jason Knorr

Posted
Posted
On 10/25/2017 at 2:33 PM, Jason Knorr said:

My 2007 Silverado went into Reduced Engine Power a couple weeks ago. It threw several codes relating to the TPS, throttle body and APP sensor. I've replaced the engine ground strap (as I've read this might be the cause), the TPS and wire connectors, cleaned the TPS ground connection on the engine block and replaced the throttle body. None of these have fixed it yet. I'm putting a new APP sensor on tonight. I'm hoping that works otherwise I have no idea what it could be. GM has a technical bulletin that says it can be caused by leaking water getting the APP sensor wires wet or by aftermarket equipment being wired in. I don't have any aftermarket equipment or a leak that I know of, but I'm going to check the APP wire connections too.

After replacing parts, the check engine light would not be on. I found that by tapping the accelerator pedal three times, the check engine light and the Reduced Engine Power message will come back on. So you might want to try that to verify it's fixed after replacing parts. Otherwise I've heard that this issue is intermittent and sometimes goes months before it occurs again.

I replaced the APP sensor and that seemed to have fixed it. Drove 900 miles and reduced engine power message or check engine light have not come back on.

carnau Enthusiast

carnau

Posted
Posted

 

On 5/19/2006 at 9:30 PM, firefighteremt3100 said:

Systematic Testing Code P2135

Replace Failed TBI Unit & Reprogram PCM

 

 

Again, I'm not a mechanic so I don't really have any idea what this is. Any help would be greatly appreciated :chevy: Have a great weekend!

I didn't want to take the time to read all of the posts. I read the first page and once I got to the dealership telling you it was an accessory I was aggravated enough knowing how many of these vehicles come in with this kind of problem (I work at a dealership and this is a once a month occurrence). A 2135 code is a correlation code between the throttle position sensor 1 and throttle position sensor 2.

 

Going to try to explain this so you can fix it without being technical since electrical is my specialty.

- First you need to the throttle body while the vehicle is running and at the connector start manipulation the harness to try to get the engine to go into reduced engine power mode. Look for white spots in the wires at the connector itself where the wire bends. Take each wire and pull in at the connector. Don't Heman the wire but give it enough of a tug that if the wire was broken or the terminal was loose it would come out of the connector or break.

- If while manipulating the wiring harness the engine goes into REP mode you know you got faulty wires and the make a harness repair kit for that. What I like to do personally is replace the 6 circuits all the way back to the control module itself (I know that sounds like a lot but it really isn't) You will need to buy the terminals though. You can just butt connect it if it makes you feel more comfortable. They come with the repair harness. The circuits in question are 416/485/452/1688/486/1704 

 

Here is the harness. http://amzn.to/2hAyR6v

If you decide to run it all the way back to the module you will need these terminals. http://amzn.to/2AfQhgm

And this terminal tool - http://amzn.to/2xWLBdH

 

Let me know what you find!

 

 

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  • 2 months later...
MB Divis New Member

MB Divis

Posted
Posted
On 7/21/2016 at 11:44 AM, SpartanAutoworx said:

I buy around 100 chevy trucks a year so I am very familiar with this issue.

 

99% of the time the reduced engine power is due to the gas pedal. I always replace that first.

 

Second is wiring going to the TB itself. Dorman makes a kit with a new harness and TB motor. I have never seen the motor fail but I have found two bad harness connections.

The third is the TAC Module on the firewall driver side. I have only seen a TACs Module fail once.

 

Replace the gas pedal and im sure all will be fine.

 

  • 5 months later...
BabyJayne Enthusiast

BabyJayne

Posted
Posted

Hi All,

I have an 03 Yukon that was getting worse with the reduce power. We were throwing parts at it for awhile but nothing helped. Then one day we noticed that the display to show what gear you were in wasn't working right. Some days it wouldn't show what gear or it would show neutral not drive. Well finally it stopped working altogether. So hubby replaced the Neutral Safety Switch. Not sure if it's the right part we replaced but it has been a month now and no problem at all. Before he replaced it it would go in limp mode within 50 feet of starting to drive and then keep doing it at least 5 times in a half hour drive. I hope this helps someone.

  • 3 months later...
2006chevy2500hd New Member

2006chevy2500hd

Posted
Posted

I have changed tps, pic tail harness, pedal, throttle body and tps. Truck still goes in the to rdp. Brought to dealer said it was wiring harness behind the pic tail harness to the fuse box. Now $650.00 at the dealer truck still goes in to rdp. 2006 chevy 2500 hd 6.0

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