Traction failed -- Service Stab Sys -- Reduced Power

[lfootmatt]

Son got this on his 08 H2 Alpha today while parked, in park after driving approx 3 miles form a cold start. 8 degrees F outside.

Here's where this departs from the norm. In park idling, engine starts revving up and down, feels like it is shifting and starts "grunting" like it is trying to get unstuck. Happened a couple more times today while he was driving, and dropped into reduced power mode and would barely go. Cycled through several cold start cycles and it went away.

I've been researching on here, but the revving/shifting/grunting thing seems unique,

Any ideas????

Thanks!

Matt

 

[mjferencak]

My H3 got the service stability control after I cut the wheel speed sensor on the front hub. See if the wires are intact. Reduced power might be a case of a dirty throttle body and/or MAF sensor. Clean both and see if that helps. That was my issue when I lost all acceleration going down the interstate a few years back.


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[alrock]

After what he said, get the battery checked too, and check the terminals to make sure they have a good connection. Low voltage can cause weird idling/driveability issues.

 

[Mr_Rich]

This is the symptom of TPS failure on the throttle body. It's been several years since it happened on my truck which is also a 3.7L but same malfunction otherwise. There may be a transient code that you can catch with a scanner. When it happened on mine I'd pull the battery cable and reconnect, then use the scanner to verify TPS functions. It would be okay for a while but I eventually replaced the throttle body since the TPS sensor is integral to the unit and it hasn't happened again.

 

[lfootmatt]

This is the symptom of TPS failure on the throttle body. It's been several years since it happened on my truck which is also a 3.7L but same malfunction otherwise. There may be a transient code that you can catch with a scanner. When it happened on mine I'd pull the battery cable and reconnect, then use the scanner to verify TPS functions. It would be okay for a while but I eventually replaced the throttle body since the TPS sensor is integral to the unit and it hasn't happened again.

Did you have the revving on its own symptom? That's the one thing I couldn't find elsewhere on the site.

Thanks,

Matt

 

[Mr_Rich]

Did you have the revving on its own symptom? That's the one thing I couldn't find elsewhere on the site.

Thanks,

Matt

Not sure what you're asking on that last question. I did post on this subject four or five years ago when mine failed. I did catch a hard code before it disappeared and the shop manual said, "Replace throttle body."

 

[Mr_Rich]

I remember the first time mine failed. I was making countless trips between the family home in eastern LA county I inherited and my home on the Central Coast. I usually would gas up in Ventura off Seaward Ave. and as I'm slowing down at the end of the off ramp is when I got the "reduced power/ stab sys" in the message center and the truck started chugging at that point. I essentially "power cycled" the truck to clear the problem and I was able to get home the next hundred miles after that. It happened a couple more times before I replaced the throttle body.