Nowadays, it feels like modern vehicles have become more like driving computers than actual cars or trucks. They’re incredibly technologically advanced, with computers and sensors controlling just about every aspect of your driving experience.
While all of this aims to make it as safe, convenient, and easy as possible for you to drive, anything that upsets the balance maintained by each sensor and module could cause a fault in the drive system, and make any number of your error lights come on.
Some can be particularly unnerving, especially the reduced engine power light, which is what we’re going to be discussing in detail throughout this article.
An engine is meant to run a certain way. If it isn’t performing as it should be, it’ll probably be pretty obvious to you. Just in case it isn’t, though, the reduced engine power light lets you know when something isn’t right.
How Can I tell When My Vehicle Is Running On Reduced Engine Power?
You live with your car almost every day, so you’re most familiar with how it functions under normal circumstances.
For starters, your familiarity with it will probably be the best indicator if you’re running on reduced engine power, even if there aren’t any warning lights displayed in your gauge cluster at the time.
However, just in case you don’t pick up on a problem, your car will. After all, not everyone’s an expert that knows what they need to look out for.
The computers and sensors that make your vehicle run are programmed with a backup setting, sometimes called “limp mode” or “safe mode”, which will automatically decrease your vehicle’s power to try and prevent damage to the engine.
Depending on the vehicle, this reduced power backup system could shut down accessory components, limit your speed, and sometimes completely immobilize your vehicle.
In most cases, your vehicle will give you just enough power to get to a shop or back home in case you happen to be driving somewhere and a problem arises unexpectedly.
What Exactly Does the Reduced Engine Power Light Mean?
The reduced engine power light comes on when the vehicle’s computer detects a fault in any of the systems that allow the engine to run optimally, such as airflow sensors, throttle sensors and oxygen sensors.
This light isn’t found in all vehicles out there, nor is it always a light in the vehicles that do have this warning mechanism.
In some vehicles, it can be a warning displayed on the screen portion of your gauge cluster, if your vehicle has a screen.
General Motors vehicles often have this light. Other vehicles, especially luxury and performance vehicles, don’t have this warning light, but do have a “limp home” mode.
It should be fairly obvious if a vehicle enters “limp mode” as discussed above, especially if the check engine light is displayed and your vehicle is severely limited in power and capability.
What Should I Do If The Reduced Engine Power Light Comes On?
If you’re driving and the reduced engine power light comes on, the first thing you should always try to do is get the vehicle back home or to a shop immediately. If you’re already at home and the light comes on, don’t drive the vehicle.
After the light comes on, the first thing you need to do is have the vehicle scanned with and OBD II scan tool.
Because of all the computer modules in vehicles, error codes and faults that occur are stored within the systems of your car or truck, even if the scan occurs after the light goes off or before it turns on.
Back in the day, older vehicles didn’t have the computer systems that newer vehicles do now. As technology grew in the 1980’s and 90’s, scanning a vehicle was possible, but didn’t always produce specific and accurate results as to the error. It could also be extremely expensive to do.
In 1996, the EPA mandated that every vehicle needed to have OBD II compatible software rather than manufacturer specific or expensive scan tools. OBD stands for “onboard diagnostics”, and OBD II standardized all the information your vehicle stores.
If you don’t have an OBD II reader, you can usually go to an auto parts store and they will scan your vehicle for free. If you do have an OBD II reader, you can see the errors for yourself.
They usually range from about thirty dollars to thousands of dollars, depending on the scanner’s capabilities.
What Might Cause The Reduced Engine Power Light To Come On? And How Can I Fix It?
There are several different reasons the reduced engine power light might come on, and all of them should be cause for concern.
After scanning your vehicle, it should be fairly easy to pinpoint exactly where the issue is coming from, especially when using a high quality scan tool.
There’s a Loose Wire, Harness, or Clamp
Your vehicle is full of wires and connectors that power everything and make it run. A short in the electrical system, a loose ground wire or a loose clamp can all trigger a fault in your vehicle.
This is usually the easiest and most recognizable issue, should it occur. However, if nothing is loose, no wires are exposed or broken and everything is correctly hooked up, you’ll more than likely need to consult a professional mechanic.
What Should I Do to Fix This?
Whenever you’re dealing with a vehicle’s electric systems, be sure to disconnect the battery first before fiddling with any wires or sensors.
Make sure all connections are in place. Check for loose wires or grounds that have become unhooked. Look for exposed or damaged wiring.
Reconnecting anything that’s loose can usually be easily done, but any exposed or damage wiring will need to be replaced.