Q: Engine in limp mode-- transmission has been checked and found to be fine. 2002 GMC Yukon XL

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Our GMC Yukon Denali is stuck in limp mode, and we've been to 4-5 different mechanics including a transmission specialist with no word on why. Check engine light was on for a bit but we replaced a bad radiator and it went off. Now it just consistently says low coolant even with the reservoir filled.

Someone early on had said it was an electrical issue but we haven't had any luck with anyone finding exactly how and have been told we may need to spend a few thousand on a new computer part. Any suggestions on next steps or chime-ins would be appreciated-- it's a great car but it limits us greatly to not be able to use it!

My car has 115556 miles.
My car has an automatic transmission.

Hi there - the first task for a "limp mode" warning is to check for problem codes, even if they are intermittent, and whether the Check Engine light is on or not. Find out what is causing the Low Coolant issue, and correct it. Many conditions, like the Low Coolant warning, can cause a "soft error", that is - something that threatens operation of the vehicle, but may not be a "hard" failure of a component. Low coolant can cause overheating, so the engine/transmission management software reduces power to avoid potential damage. If a bad sensor condition sends a "soft error" warning, the system reacts as though the problem is real. I recommend a loss of power inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

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