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I tried searching on here for anyone that experienced limp mode. I was driving about 40 mph and used the paddle shifters then the engine light came on and the D was flashing and speed limited to first gear. I was close to my buddies shop. He said it's most probably limp mode. He disconnected the battery and ten minutes later everything was perfect. I'm confused on why this would happen by downshifting with the paddles. Any one?
Are you sure it limped into first? The RPM would have climbed to near redline because maximum speed in first is about 45 MPH at governed RPM. Typically the 8L90 will choose 4th as its safe limp mode gear if a problem occurs-usually due to a communications issue between the ECM and TCM.
Go ahead and have it scanned for a stored code. Agree with 383 that you don't want to just clear a DTC to turn of the CEL without recording the code because that throws away valuable diagnostic data.
I tried searching on here for anyone that experienced limp mode. I was driving about 40 mph and used the paddle shifters then the engine light came on and the D was flashing and speed limited to first gear. I was close to my buddies shop. He said it's most probably limp mode. He disconnected the battery and ten minutes later everything was perfect. I'm confused on why this would happen by downshifting with the paddles. Any one?
Happened to me on a 75 degree day, while in D (not paddle shifting). DIC said engine overheat / engine power reduced. Good times.
Last edited by Big Lebowski; Dec 31, 2017 at 03:08 PM.
Do an internet search for "OBD II code scanner" and you'll find a zillion places from eBay and Amazon, to just about every auto parts store, to Walmart, and Home Depot.
You'll find prices from less than $20 to several hundred $$$ at different places and for different features.
You want an OBD II CAN capable scanner. Most do not read ABS codes, but Harbor Freight has one for $140 that will read ABS diagnostic codes.
Here's what one looks like - I think I got that picture from a Walmart site. You can see it has a plug you connect to the OBD II port:
I bought my Innova scanner via Amazon about 4 years ago when I was doing some diagnostic work on my 2006 GMC Sierra diesel equipped pickup and I have been happy with it. As BEZ06 noted there are a lot of different scanners available including those that work with smartphone apps but I wanted a decent dedicated unit that handled CAN bus, could read the separate transmission controller codes for the Allison transmission in my pickup, and could display live data frames.
Remember how you never used to always keep a jack and a spare in the car with you? Well with runflat tires on most vehicles that isn't a concern anymore but whichever vehicle goes on a trip WILL have the Innova with it. In 2016 my Z06 threw its first Range anti-AFM module induced code while on vacation in the Smoky mountains and I was able to quickly identify the reason and erase the code using the code reader. It is one of those tools you won't need often but it is very valuable when it is needed.
Most auto parts stores can/will scan your codes. In my limited need I can't justify a $50 or more tool when a $15 tool will give me the system afftected & codes. But as others have said do not clear them until a professional has examined them. Just clearing the code will not eliminate the cause for the CEL/Code to be thrown.
Last edited by madrob2020; Dec 31, 2017 at 03:49 PM.
I think it's worth mentioning that an overheat limo mode doesn't speed restrict you to sub-60mph speeds. It simply limits RPM. It sounds like you had an issue other than limp mode.
i experienced it when the car had been sitting for a while. Barely started due to a low battery, was in limp mode as I put about three miles on it. Let it set for a bit started it and it ran fine after the battery charged
Update
Dealer went through it and stated that the code was gone since I unplugged the battery. They went through all the systems and have it a clean bill of health. I think i will buy a code reader on amazon. Like 40$. Just to have for the codes.
I wouldn't be without a scanner now but if you still have a current OnStar subscription they can pull most codes for you while you are driving so you can consider that as an alternative to the code scanner.
When my 2006 GMC pickup was almost new I was taking my 3 year old daughter camping in Colorado and was accelerating out of an Iowa rest stop when the CEL came on. The vehicle came up to speed and operated normally so I merged onto the interstate and had OnStar retrieve the code and it was a non-critical EGR flow issue. The CEL turned off after a few starts and I waited until my return to IL to have it repaired. A code reader would have been useful then but the oft maligned OnStar was worth its weight in gold knowing I didn't have to go searching for a repair shop in the middle of nowhere, Iowa on a Sunday morning.
I wouldn't be without a scanner now but if you still have a current OnStar subscription they can pull most codes for you while you are driving so you can consider that as an alternative to the code scanner.
When my 2006 GMC pickup was almost new I was taking my 3 year old daughter camping in Colorado and was accelerating out of an Iowa rest stop when the CEL came on. The vehicle came up to speed and operated normally so I merged onto the interstate and had OnStar retrieve the code and it was a non-critical EGR flow issue. The CEL turned off after a few starts and I waited until my return to IL to have it repaired. A code reader would have been useful then but the oft maligned OnStar was worth its wait in gold knowing I didn't have to go searching for a repair shop in the middle of nowhere, Iowa on a Sunday morning.
Oh wow. Thank you. I do have onstar. I thought onstar Is good for four years but that may just be for the basic features.
Limp Mode
