AddisonD

2011 GS 6-spd manual:
I have had a few experiences in recent weeks of randomly getting the “Service Traction System” and “Reduced Power” messages, and the check engine light comes on. This has happened when I was driving slowly on my local residential streets. It is not connected to any type of maneuver or street conditions.

After getting the messages, I’ve then stopped and turned off the engine.
When I restarted, the warning messages are gone and the power is normal, but the CEL is still on.
However, when I start it the next day, the CEL is cleared and everything is normal.

I have owned this car since 2013, and this has never happened until the last month or so. It is currently at about 17k miles. It has new tires and battery within the last 2k miles.

What could be the cause of this, and is there any way a mostly non-mechanic person (me) can address it, or will this require a trip to a knowledgable shop?

Many thanks for input and guidance.

C5 Diag

There can be multiple issues which will cause this so unfortunately this won't be easy to diagnose here over the Internet...since the MIL (check engine light) is on the problem is going to be something related to engine emissions which will be a P or Powertrain code on a scan tool...it won't be something like a wheel speed sensor which would activate a "C" or chassis code in which the check engine light will NOT illuminate...I’m “thinking” maybe electronic throttle control related ???…if for instance the problem resolved itself and everything was OK the check engine light goes out after 3 ignition cycles...even something like a misfire will activate the STS light and check engine light...you will need at the minimum a scan tool to see what the code may be and then figure out the cause...your friendly auto parts store can read the code for you…I do have someone I can highly recommend in Pasadena,Texas...Azael (Oz) is a real sharp diagnostic Tech...you don't want a repair shop "wrench turner" or a dealership to diagnose this...they are usually clueless and will only guess which will be expensive for you…good luck and if you use Oz let us know what he finds !!

Patsgarage

Forget the mileage on the battery, how old is it ?

AgainstTheWind

this

some corvettes on this forum don’t see 2,000 miles in ten years. 🤔

your symptoms point to the battery

AddisonD

GEE - good input!

@C5 Diag I appreciate the insightful reply. I will definitely use the knowledge, and your tech person, Oz, sounds like a great person to know.
He is located a long way from me, but it is not impossible to get there.

Regarding the battery comments, thank you - you might have me on the right path there.
I need to check the actual records which I don't have available as I sit here to type right now.
I am thinking that the battery was replaced circa 36 months back, but I admit to being a little unclear about that.
The battery takes a charge and holds it quite well I think, but it might be falling below some critical output level that I am not even aware of.

.

I will report back once I have something further.

AddisonD

I put up with this situation until about a week ago. The "service suspension" light, always accompanied by a check engine light, had come on 2-3 times at random since I first posted this thread, and then it was all cleared the next day.

I finally had my long-time trusted local shop take a look and they were able to analyze that it had a intermittent problem with the accelerator position sensor. That was a relatively simple replacement, and it is all's well now.

What irritates me about all "modern" cars is the seemingly endless array of sensors that lead to such situations. I also have a 1998 vehicle that I have owned since new, and I love its relative simplicity. I am totally certain that it does NOT have any sensor to determine the position of the gas peddle.
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