Richie Fazio

Hi All. Hoping folks can provide some insight. I have a 2015 m7 Z stock with 35k miles. No issues at all until yesterday. I was driving in the highway at 60mph and I downshifted to 2nd to get off and exit to drive into my town and the car all of a sudden went into limp mode and reduced power check engine came on. It was very scary and I somehow managed to drive it slowly into 1st gear into a nearby parking lot. I opened the front hood and there was no engine smoke or anything. I tried re starting a couple of times but car remains limp and there is a rough idle. I also received a check rear axle light. I ended up having the car towed to a nearby Chevy dealer and they should look at it this week. I haven’t driven the car much this summer, and I recently had the oil changed. Also have new breaks, struts, pads and tires on the car. I also drove for about 45min on the highway in eco mode (not sure if that matters…)

I’ve seen a few diff threads on subjects similar to this but I wanted to share my specific story for any help or guidance. It was pretty scary to have this happen getting off an exit with cars behind me. Anyone have any ideas what happened and how to fix it? Thank you!

need-for-speed

Could be a rear wheel sensor not connected properly when the recent work was done.

Richie Fazio

interesting. So that could cause reduced engine power etc? Thanks!

Bill Dearborn

A wheel speed sensor would cause the ABS, TC, and Stability Control to fail and light their lights on the IP. CELs are mostly caused by engine problems that affect emissions and are never caused by wheel speed sensor errors. A rear axle error message would also be displayed if there was an engine code set that prevented proper control of engine torque.

Without knowing the codes the first thing to look at when something like this happens is loose plug wires, low battery, and dirty/corroded battery connections at the battery and frame. If you can get the codes read that will provide more detailed things to look at. There are diagnostic test procedures/steps associated with each DTC that help a person figure out where a fault is located.

Bill

Harbgrogan

I just dealt with a reduced power situation very similar sounding to yours. Car went into limp mode on the freeway and shut down. When started it was rough and could barely move so I had to tow it back to my house. The codes will really help you narrow it down, I had the P2101 and P1516 and actually was logging when it happened and saw nothing bad aside from the TPS pegged at 32%.
After checking the battery and all my wiring for shorts or open circuits I did a static resistance test on the TB motor and it was bad. Replaced it and everything is perfect again. So there is a chance it is a small fix for you as well, good luck. At first I thought I blew the engine!

Richie Fazio

thanks. I sure hope so. I wasn’t going fast at all but who knows. It’s at the dealer so hopefully they will know what to look for and do in response to these codes. That limp
mode is really scary. I’m sure there is a reason it happens but it’s dangerous especially when on the highway

Bill Dearborn

When something fails on a modern car the first thing to do is to check the codes. That goes for an engine problem, a braking problem, an AC problem, headlight problems, or even a seat problem. A significant number of the codes won't register on an OBD II reader since they are only meant to display standardized Emissions related failures.

Bill

Maxpowers

As mentioned it could be a bunch of things and Id start with codes. Mine was the gas pedal sensor due to a loose wire. Felt like an idiot driving so slow on the highway for a brief period.

Dale06

Interesting. Probably not comparable, but my Silverado ( not my Z06) did exactly the same thing two months ago. Had it towed to dealer. Code said a broken wire between transmission and motor. Simple fix and back on the road.