If you own a car with part-time 4-wheel drive, then you’re likely aware of the switch that allows you to toggle between modes.
However, if you find that it isn’t working, it may be due to a problem with a component called the transfer case control module. Here’s what I found!
Transfer Case Control Module Symptoms
1. 4-Wheel Drive Isn’t Working
One of the most obvious indications of a faulty transfer case control module is that the 4-wheel drive mode isn’t working.
When this happens, pushing the switch panel to engage the 4WD sometimes has no effect.
Therefore, to establish if you need to alter this component or not, you must run a TCCM self-test.
As such, watch the transfer case shift control switch indicators as you turn the ignition since a working TCCM will flash each indicator before switching back to the onboard gear.
2. Grinding Sounds
In addition, one of the first signs of a faulty transfer case control module is grinding sounds.
Generally, the TCCM is made of several moving parts, so if you hear grinding noises after the module switches the mode your vehicle is in when you click the button to engage or disengage the four-wheel drive, there may be a problem.
As such, it still indicates that there is a problem with the module even if it functions; this can be damaged gear, road debris, or something else entirely.
3. Difficulty Shifting Gears
Aside from my points above, having trouble switching between the two gear ranges is a clear symptom of a damaged transfer case control module.
Although the issue may be brought on by a broken linkage or low fluid, it typically points to internal transfer case failure.
However, to operate the TCCM, be sure to adhere to all the instructions provided in the user handbook for the vehicle, otherwise, you risk giving an incorrect diagnosis.
In many circumstances, the automobile must be stopped and the transmission must be put in neutral before shifting into four-low.
4. Fluid Leaks
Fluid leaks around the transfer case area may also be indicative of a faulty transfer case control module.
In this scenario, the only explanation for the fluid pooling directly under the transfer case region is that there is a leak.
As such, if you jack up your car and check under the hood, you may see if the leak is most likely originating from the transfer case.
Additionally, the leak at the back of the transmission or transaxle assembly should be clear to notice.
5. Engine Hesitation
In addition to the points above, a faulty TCCM is one of several things that might make an engine stutter.
Typically, driving while the engine stutters excessively could indicate a problem with the transfer case control module.
Moreover, the transfer case control module may be sending incorrect signals to your car’s transmission, resulting in your engine stuttering while you drive.
As a last resort, you’ll have to replace the transfer case control module to resolve this problem.
6. Wrong 4WD Indicator Light Displayed
Another symptom of a bad transfer case control module is the wrong 4WD indicator lit up on your dashboard.
Generally, when you engage or disengage 4WD on your car, a sign will light up on your dashboard to let you know what you selected.
However, if you change gears and it doesn’t reflect the correct setting on your dashboard, this may be due to a transfer case control module error.
As such, this should be checked right away as it can be dangerous to drive with an incorrect drive setting.
7. Check 4WD Light on Dashboard
In addition, a service warning light for the 4WD may be a sign of a faulty transfer case control module.
Generally, when the system isn’t working properly, some car models will have a “service-four-wheel-drive” notice that flashes on the dashboard.
However, other cars simply leave the 4WD light on until the issue is resolved.
As a result, the problem is likely to be due to a faulty transfer case control module.
8. Excessive Front Tire Wear
While not a direct result, extreme wear on your car’s front tires may be a symptom of a bad transfer case control module.
Generally, the transfer case control module is responsible for the transfer case, which determines when your car shifts from 2WD to 4WD.
As such, if the TCCM isn’t working, then this may result in your car not disengaging the 4-wheel drive setting.
Further, this may result in the front tires wearing faster than the rear because the front tires do most of the braking and steering in 4WD cars.
9. Poor Fuel Economy
Moreover, poor fuel economy may also be a sign that you have a faulty transfer case control module.
As I mentioned above, a transfer case control module error may cause your car to not disengage 4WD.
However, since a 4WD system requires more working components than a 2WD system, driving in 4WD consumes more petrol than driving in 2WD.
As such, more moving parts require more fuel to power the drivetrain which means bad gas mileage.
To know more, you can also read our posts on why electric cars are safer, why Jettas are so cheap, and why your gears are slipping.
There are several factors to consider if you suspect problems with your car’s transfer case control module, including the 4WD not working.
Additionally, noises and oil leaks can be serious problems that indicate something is wrong with the TCCM.
Therefore, the best course of action is to have your transfer case control module’s codes checked so you can determine how to correct it.