Well, do you know what to do if your 4WD goes into limp-home mode?
Words and Images by Gary Tischer
Picture this, you are at your favourite camping spot or in the middle of the Simpson Desert and your Check Engine light comes on … do you want to know what your next step is? Well it’s your OBD-II port, which may very well save you!
If you haven’t experienced limp mode, the vehicle basically puts itself into 2nd or 3rd gear and stays there (assuming it is an automatic). This isn’t just a hypothetical. This is exactly what happened to a Land Rover Discovery I saw in the Simpson Desert recently. That vehicle ended up on the back of the tray-back recovery vehicle out of Birdsville. It couldn’t climb the dunes by itself.
If you think it could only happen to a Land Rover, then talk to someone who owns a Toyota HiLux, Prado or Fortuner with the 2.8-litre turbo-diesel. It may go into limp mode if the mass airflow sensor (MAF) is contaminated by dust. Last time I was outback, there was a fair bit of dust about. On a recent road test, it happened four times to the HiLux test vehicle (read more about it here).
WHAT IS OBD-II OR OBD2?
Since the mid-1990s, most passenger cars and light trucks have had On Board Diagnostics (OBD) and in 1996, OBD-II (or OBD2) was created as an open standard so that emission standards could be maintained and vehicle manufacturers could keep their engines compliant. This had additional benefits for analysing other systems on the vehicle.
When you take your vehicle for a service, there is every chance that the mechanic will connect to your OBD2 port to check if everything is okay. When there is a problem, a code will be displayed on the mechanic’s equipment. The mechanic will check what the code means and fix the problem before clearing the code.
If the ECU senses a problem or malfunction, it will trigger a fault code and may turn on the Check Engine light. In turn, this may put it into limp mode. If you are in the Simpson Desert or the bottom of a steep hill you may be stuck, as limp mode will greatly reduce the power or gearing available.
The problem may be something serious or perhaps not. When you are bush, you can’t really duck into your local mechanic for them to check it out like you could if you were in the city. Or can you?
CONNECT TO YOUR OWN OBD2
This is where you can be the master of your domain. By using one of various devices and/or phone apps, you can connect to your OBD2 to see what the fault code is and get an indication of what triggered it. You can then contact your mechanic via phone or satellite phone to find out what the code means and potentially clear it.
If you can do this, you will be on your way again very quickly. It also could be something serious enough that you will need to be recovered. If this is the case, you will hope that your insurance will cover it.
OBD2 READERS AND APPS
There are quite a few OBD2 readers and phone apps on the market. I have both a Bluetooth OBD2 reader connected to an app on my phone and a ScanGauge II. Although the phone app has more detail and great graphics, it is sometimes difficult to connect. The main reason I don’t use the Bluetooth reader as my main OBD2 reader is that for fuel economy and some other functions, it needs to be on all the time and will stop recording if you are using another app, such as playing music.
The ScanGauge on the other hand is always connected and gives plenty of information while operating separately from anything else. The graphics are rudimentary but the information is solid. One of the reasons I purchased the ScanGauge was that it has great documentation, which walks you through the functions even if stuck in the middle of the desert without communications.
OTHER BENEFITS OF OBD2 READERS
As well as identifying and clearing fault codes, there is a wealth of information that the devices and particularly the ScanGauge can tap into. My FJ Cruiser doesn’t have much in the way of information available on the dash as standard, but I can see up-to-date info on how many kilometres I have until the tank is empty. This is particularly useful if you have added a long-range fuel tank.
The ScanGauge also has what is called X Gauge, which allows you to display information not normally available across different vehicles. In the FJ for example, I have been able to add the automatic gearbox oil temperature both in the pan and at the outlet. This is particularly useful when towing.
An OBD2 reader is a relatively cheap way of providing peace of mind when going remote, and also provides a wealth of accurate information that can be used to ensure a safe and happy trip. Obviously, if you are going to call your mechanic from the back of beyond, you’ll need a satellite phone, but that’s another story …