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Dan, Technician
Category: GMC
Satisfied Customers: 24212
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Databases
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GMC Yukon XL 1500 SLE: Bought a 2004 Yukon xl last year and

Customer Question

Bought a 2004 Yukon xl last year and have been having problems with reduce engine power. Very Dangerous had it to the shop six times still having problems
Submitted: 2 years ago.
Category: GMC
Expert:  Dan replied 2 years ago.
Hello, my name is***** you know what diagnostic codes your getting? Thanks.
Customer: replied 2 years ago.

There have been several type over the last year. The last 5 have been for throttle body. I had it replaced (second time, first was last October) yesterday, drove it five miles and "check engine" "TC" and reduce power and came on. What was different yesterday, I was pulling into a stop sign when it happened and it stalled the engine. Usually it just reduces power to the engine. I let the truck sit at the intersection for a minute and restarted the engine and regained full power to the engine an was able to get home.

Expert:  Dan replied 2 years ago.
There are a few different things that can set this warning so we will need the codes. The most common problems are wiring, throttle body, and accelerator pedal assembly. Let me know when your able to get codes checked, thanks.
Customer: replied 2 years ago.

the code it keeps throwing is a p2135. put a new throttle body on it (did not work) Mechanic says I'm losing voltage thru one of the sensors. It throws the code every time I drive right about the time the vehicle reaches normal operation temperature.

Expert:  Dan replied 2 years ago.
Locate the grounds at the rear of both cylinder, G103, G104. Remove clean and replace grounds G103 and G104. I'd also consider replacing the throttle body connector, they are common to have problems causing this code. Let me know how it goes or if you have more questions, thanks.
Customer: replied 2 years ago.

Mechanic found a lose ground. cleaned and tightened. he was not happy that there was still differences in the sensor(s) data. But while test driving despite the data not matching up the engine has not gone into reduced power mode. Put about 100 miles on it so far so good.