Mercedes-Benz Low Range Issue

The Low Range function can put the transfer case into the lower gear range for more power/higher torque at the wheels. The maximum speed is limited to approximately 50 mph when Low Range is engaged. Low range is not meant for everyday use. While the top speed is limited, the torque to the wheels is increased. All-Wheel-Drive (4WD) system is always engaged on your Mercedes-Benz ML.

Low range increases the torque by switching to a higher gear ratio to allow the vehicle to tow heavy loads or drive on steep off-road terrain.

When should you use the Low Range Function?

Use the LOW RANGE mode under the following conditions.

• Off-road driving
• Going up on steep inclines
• Towing heavy loads
• Driving in mud
• Driving in water, such as crossing a river. Up to 20 inches / 0.5 meters of water maximum.

NOTE:

Do NOT engage in snow. The ETS/ BAS system will help you when it snows. More torque (LOW RANGE mode) will make it more challenging to drive in the snow.

DO NOT USE CRUISE CONTROL WHEN IN LOW-RANGE MODE

You should engage the low range several times a year to avoid problems.

How to put Mercedes-Benz SUV (example ML320) in LOW RANGE mode

To set your ML in LOW Range mode, you need to:

1. Stop the car
2. Make sure the engine RPMs are under 1500
3. Press the brake pedal and move the gear selector to the Neutral position.
4. Press the LOW RANGE switch on the dashboard for a couple of seconds.

You should see the LOW RANGE light flash on the instrument cluster three times.

When your Mercedes-Benz switches to LOW RANGE mode, the Low Range light will constantly stay ON.

To get the car out of LOW RANGE, follow the above procedures. When you press the low range, switch the LOW RANGE light to flash three times, then turn it off to indicate that you have completed the procedure.

Low Range Light Flashing

If the LOW RANGE indicator lamp flashes/blinks after you turn on the engine and start up the car. It will flash three times or about three seconds and then turn off. It means that the LOW RANGE function on your Mercedes-Benz is malfunctioning. The Low Range light will blink without the driver pressing the button to engage low range. It will also flash when you press the low-range switch. This could be due to several reasons:

• Transfer Case Motor Selenoid Stuck (Due to corrosion)
• Transfer Case Control Unit Defective

Mercedes-Benz even issued a service campaign for the transfer case control unit problems. Download the PDF file below to read the details of the campaign.

ML Control Module Campaign 1998060001 (Source: workshop-manuals.com)

What does it mean if the Low Range Light Blinks

If the Low Range Light flashes thrice and then goes off when you start the car, you can generally drive your Mercedes-Benz SUV (such as ML320 or ML350). It just means you can now engage the Low Range if you try to go off-road – on a steep incline.

Troubleshooting Tips

If the Low Range light is blinking / flashing and does not stay on, it means that there is a problem. The next step to diagnose the problem is to get an advanced OBD-II code reader to retrieve the fault codes from the ABS/ETS/ESP modules.

You will need a diagnostic scanner, such as YOUCANIC full system scanner. You can find scanners on Amazon at a very reasonable price. Using the scanner is very simple; follow the steps in the following video. In this video, you will see how to use the scanner to retrieve the fault codes from the Airbag module, but you will need to read the fault codes from the Traction Control module.

Possible Solution

The most common problem is the transfer case motor losing synchronization or getting stuck due to corrosion and the fact that it rarely gets used.

The first thing that you should try is to repeatedly engage the low range mode. Try several times, at leat 15 times to see if the low range will engage.  If the motor does not engage (syncronize) that means that the transfer case motor most likely is defective.

The transfer case motor can be easily replaced on your ML. Below is a picture of the transfer case motor.

Transfer Case Motor on an ML320 part number 163 540 09 88 

If your ML is stuck on the low range, you could replace the transfer case motor, or you may be able to fix the problem by replacing the transfer case motor gear.

Here is a helpful video: DIY Low Range Transfer Case Motor Removal and Replacement, if you decide to replace the Low Range Transfer Case Motor yourself.

If you can not get a hold of a replacement transfer case motor, you may want to try the trick mentioned by a Mercedes-Benz owner on MBWorld. 

 

What is the Best Scanner for my Mercedes-Benz?

The YOUCANIC full system diagnostic scanner is an essential tool for Mercedes-Benz owners and technicians looking to troubleshoot problems with their vehicles. This diagnostic scanner can help diagnose issues with the engine, transmission, brakes, airbag, ABS, steering systems, and more by reading and interpreting fault codes stored in the car’s computer system. With this information, you can make informed decisions about repairs and maintenance, saving time and money.

In addition to diagnosing problems, the YOUCANIC scanner can also reset maintenance reminders and service indicators, ensuring that your vehicle is maintained correctly and preventing potential issues from occurring in the future. This feature is handy for Mercedes-Benz owners who want to stay on their vehicle’s maintenance schedule without visiting a dealership or a mechanic. Overall, the YOUCANIC full system diagnostic scanner is a valuable tool that can help you keep your Mercedes-Benz running smoothly and reliably for years.