Let me start by saying that pretty much all modern-day cars come equipped with the OBD system. It’s an automatic On-Board Diagnostic mechanism that keeps track of the most important systems in the vehicle and takes measures when a critical issue is detected. Its main job is to prevent serious damage to the motor and the transmission. It’s a self-diagnosis device that also serves as a reporting and monitoring tool for mechanics and technicians.
When the Limp mode is activated, it limits the throttle response, max RPMs, “traps” the transmission in the lower gears, and, overall, reduces the power output. However, while it is, indeed, a great system, sometimes, it doesn’t switch itself off when you fix the issue. That’s why today, we’ll learn how to reset the Limp mode on a Dodge vehicle.
As mentioned, the Limp mode aims at protecting your vehicle and its most important (and expensive) systems. It locks the transmission to the 2nd gear and doesn’t let you gain speed, thus keeping the car safer. That’s more than enough power to reach a safe spot or to drive to the nearest auto shop for help. So, a dramatic loss of power is the most obvious side effect of the Emergency mode.
Keep your eye on the speedometer. If it’s jumping up and down and showing inconsistent performance, the problem is not with the Limp mode. However, if it’s stuck at 40 miles per hour and isn’t climbing any higher, then you’re dealing with the OBD system. The RPMs, by the way, will be limited to 2-3K revolutions per minute. Plus, you’ll feel a super slow response from the Dodge upon acceleration. Last, but not least, the Check Engine light might come up.
We just discussed a long list of Limp mode side effects. But what about the issues that actually cause it? Well, it’s usually the little things, like a dirty/malfunctioning MAF sensor. It sends the wrong signals to the onboard computer, forcing the OBD to activate the Emergency mode. In other gases, it can be a damaged or leaking gasket. Transmission failure is another common cause.
Yes, mostly, this has to do with the engine, gearbox, and the adjacent systems/gear. In my experience, spark plugs can also be an issue that triggers the Limp mode. When this happens, the Check Engine light will come up on the dashboard and stay there permanently or start flashing until you fix it. Engine misfire, poor performance, and clanking sounds are the result of faulty plugs or ignition coils.
Sometimes, the ODB mechanism is triggered by a faulty cold air intake system, header, catalytic converter, bad wires, and even a leaking battery. But, this happens very rarely and only when you’ve got aftermarket parts installed.
Most importantly, when your car enters the Limp/Emergency mode, don’t ignore it. Sadly, that’s what most drivers do, but it can lead to dire consequences, including engine failure. I always recommend reading the fault codes with an OBD-II scanner. You can get a decent device for 60-70 US dollars, and it will transcript the codes. Or, if you don’t know the first thing about trouble codes, ask a mechanic to help out.
A quick note: mostly, it’s the ECU (engine control unit) and the TCU (transmission control unit) that activate the Limp mode. Now, pretty much any OBD-II scanner can read the ECU fault codes. However, for the TCU codes, you’ll need a multi-system scanner. That will cost twice as much (up to $150).
Ok, we start the Dodge limp mode reset routine by restarting the motor. Park your Dodge vehicle in a safe place, away from traffic. Turn off the engine, let it stay idle for at least a minute or two, and restart the motor. If you’re lucky, that will fix the problem right up. You’ll instantly feel the difference in performance if the restart was a success. And if the Limp mode doesn’t go away, diagnose the car once again using the OBD-II scanner.
Keep your eyes on the dashboard: chances are, the engine will start to overheat. When that happens, give it some time to cool down to avoid any potential damage. As I mentioned earlier, engine failure is the biggest side effect of the Limp mode. It will only happen if you neglect it for too long, which is why it’s very important to fix it ASAP.
Another thing you can do is inspect the transmission fluid level. If the gearbox is running low on fluid, that can be the cause of the Limp mode. Park the car, but this time, keep the engine running to warm up the transmission “lube”. Grab the dipstick (you’ll find it where the gearbox meets the engine), clean it up, and put it back in. Next, take a good look at the markings: the fluid level should be very close to the “warm” mark.
If it’s much lower, that means only one thing: you need to add some of that fluid. And don’t forget to put the dipstick back where it belongs once you refill the fluid. This is important: refer to your manufacturer’s manual before doing anything with the transmission. I know I said to run the engine to warm up the fluid, but the manual might suggest otherwise.
So, you’ve tried resetting the engine and refilling the transmission fluid, but nothing seems to be helping. What you could do next is clear the fault codes using the OBD-II Scanner. That’s right: it’s capable of not only reading but also clearing certain codes. Again, it would be best to use a multi-system scanner to clear the codes both from the engine and transmission modules.
Statistically, code clearing is more effective when it’s done after restarting the engine, keeping the transmission lube full, and running a full scan of the system. Oh, and this won’t take much time or effort: you will only have to press one button, and the scanner will do the rest.
That’s pretty much all I have to say about the Limp mode, dear readers! Today, we learned about its most common symptoms slash side effects and causes. Plus, we discussed the most effective ways to reset the Limp/Emergency mode and bring things back to how they used to be before it was activated. For that, you’ll need a decent-quality OBD-II scanner.
It will tell you exactly what’s wrong with the Dodge and help to find a solution. Resetting the engine, filling up the transmission fluid, and clearing the codes – that’s what every driver can do to try and fix the issue. And if you still have some unanswered questions, don’t hesitate to hit me up in the comments. I’ll do my best to get back to you!