I had this happen last night.

It was -24'C, and I was coming out of work. I went to start the H3, and when I turned the key, nothing happened. I initially thought my battery was dead.

I turned the key to "off" and tried again. This time, it started, but immediately stalled after running rough. I started again, this time giving it some gas. After I let go of the pedal, it stalled. I tried again, and this time it stayed running, but very very rough, with RPMs ranging from next to 0 all the way to 1200. Several failures were reported, including:

- Reduced Power
- Stabilitrak Failure
- Service Engine

I called OnStar. They patched me into an expert because they said it was very serious. He said something about throttle body, accelerator sensor, and some others. He said I shouldn't drive it. He patched me into the dealer (who was closing in 10 minutes). The dealer said no point in bringing it in as they were closing, and recommended I try and drive it home. I started driving, but using the accelerator didn't do anything (all I got was a crazy up/down idle speed). He suggested I pull over, and shut it off, wait 30 seconds, and re-start it. I did that, and it seemed to start fine, but the errors were still reported.

We'll see what the dealer says. I've sent them an email this morning to get it booked in for service.

 

Had one of my chevys do the same thing last week. would start and die as if the fuel pump was failing and would run very rough up to about 2000rpm then smooth out and as soon as gas was released it would die. turned out it was the crank shaft positioning sensor. runs great now.

 

This happened on my H2 once. It turned out to be a bad throttle position sensor. The dealer fixed it very fast for me.

 

I didnt read anyones responses forgive me, but our 6L suburbans we use on missions here get it all the time. We usually get half power instantly when it flashes reduced engine power. Once was because a sensor for the engine temp was on the fritz another time it was something with the throttle position sensor and once was because the computer itself went bad. We get it all the time over here most of our suburbans dont even have 30k miles on them and they go through all this hell. Our master GM mechanic always has no problem hooking it up to the computer & diagnosing it. For most though it is a temp issue.

 

It started fine yesterday morning, and the engine lights went out. I called the dealer, and they suggested that it would be a waste of time to bring it in, because if the engine light isn't on anymore then the error codes have been cleared by a "self-diagnostic".

He said (which makes sense) that some moisture probably got into the throttle body and when it froze the other day, it stuck the throttle into a particular position. The computer was trying to open the throttle and it was frozen, and that's what made it run rough. Once the engine warmed up (and I shut it off to reset it), it ran fine, which (to him) indicated that the ice in the throttle had melted.

 

most computers hold the code untill someone clears the codes. i had codes come up regarding stabil track and other 4wl issues and they went out also the dealer told me that when they ran a check they found that some calibrations were needed and that they flashed the computer to clear any codes that may have been stored.

 

i had my reduced engine power displayed on my dash. has any came across this problem and if so whats the problem? what part needs to be replaced? can anybody being mechanically incline replace or is it a dealer problem? thanks for the help

 

Hi San ,

I had the same problem last night but fortunatly it ran up ok this morning.
Sometimes moisture can enter a speed sensor wich is pretty commom....so give it a go tomorrow and see what happens.
Good Luck

 

Today was the second time it HAPPEND to me first it was the gas pedal now the plug that connects to the throttle control had a split cable

 

Issue: Reduced Power.
Cause: HID Xenon headlights.

Removed the ballast/bulbs and issue solved. Seems the power surge from the ballasts coming on was causing the computer to reset.