Service 4 wheel drive light is on

The light for service 4 wheel drive e keeps coming on and off

My car has 155340 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi there. A faulty solenoid or motor on the transfer case, an inoperative front differential actuator, or simply a bad switch could all cause the 4WD light to illuminate on your dash. It’s a good idea to have an inspection of the four wheel drive system by a professional mobile mechanic at your location to determine the source of the problem and recommend a solution.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

When the 4WD light appears, it is letting you know that there is an issue with the 4WD system and it must be handled promptly. Another reason why this light may occur is an incomplete shift in gears. This is confusing and damaging to the engine and could result in your 4WD service light flashing continuously.
To reset the Change Oil light turn the ignition on but do not start and then push the gas pedal 3 times. The Service 4WD light is most likely the 4WD switch on the dashboard. If the lights are acting funny then the switch needs to be replaced.
“Also known as four-wheel drive, 4WD is a system distributing power equally to all four wheels, and is most appropriate for off-road conditions.”
The 4WD transfer case encoder motor position sensor or the selector switch may fail causing the service 4WD message to be displayed. Fault code(s) stored in the transfer case control module will be of assistance in determining the exact fault causing the message to be displayed.
If the AWD light isblinking rapidly, your powertrain oil temperature is much higher than it should be. Pull over in a safe location, as soon as possible, and idle in park to let your engine cool down. You can drive again once the oil cools down, but you should still get to a service center as soon as possible.
You should get in the habit of having regular maintenance checks before and after every off-road trip — as exposure to mud, water, dust and dirt causes parts to wear out faster. Preventative maintenance and routing inspections are the key component to avoiding breakdowns out on the trail.
Know how to engage and disengage your 4WD

However, most 4WD systems can now be shifted into or out of 4WD on the fly at the push of a button. The most sophisticated 4WD systems are fully automatic. They shift into and out of 4WD automatically as the system detects the need for more traction.

In some cases, no more than 30-36,000 miles. And in some cases it may be as frequently as every 15,000 miles. Also look for any kinds of leaks when you`re under it.
A flashing indicator light is typically caused by wiring or an electrical component like the controller, a faulty motor or fork, a speed sensor, or a position switch. Many 4WD units have an actuator located on the front axle to lock and engage the front axle for 4WD.
Transfer Case Control Module (TCCM) is the brain behind the electronically shifted 4WD systems. The TCCM processes the shift request from the dash mounted mode selector buttons, executes the shift, and verifies the shift was completed. Replace your current failing or faulty item with this direct replacement.
All-Wheel Drive: For vehicles equipped with AWD, a blinking indicator light means that the system has overheated or malfunctioned and requires immediate service. A steady light means the system is engaged.
Know how to engage and disengage your 4WD

However, most 4WD systems can now be shifted into or out of 4WD on the fly at the push of a button. The most sophisticated 4WD systems are fully automatic. They shift into and out of 4WD automatically as the system detects the need for more traction.

All-Wheel Drive: For vehicles equipped with AWD, a blinking indicator light means that the system has overheated or malfunctioned and requires immediate service. A steady light means the system is engaged.
Know how to engage and disengage your 4WD

However, most 4WD systems can now be shifted into or out of 4WD on the fly at the push of a button. The most sophisticated 4WD systems are fully automatic. They shift into and out of 4WD automatically as the system detects the need for more traction.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Can front wheel drive car engine power rear wheel drive
ANSWER : Anything is possible with enough engineering. The changes you are looking at would take major structural changes and would definitely not be an easy job. You could possibly consult a manufacturing engineer to get more details on how this could actually be carried out and whether it would be feasible.

The service 4 wheel drive light comes on in my 05 Chevy Silverado 1500 HD
ANSWER : It is not likely that damage will occur or is occurring. Generally, it’s only if the check engine light is actually flashing that you can reasonably expect damage. As far as whether what you are describing is a "known issue" or not, there are many GM Technical Service Bulletins for your year, make and model that refer to the Service 4WD indicator. A brief list of these TSB’s appears below. If you desire that a certified Mechanic inspect your vehicle and determine if any of the below TSB’s are applicable or, if not applicable, simply pinpoint the problem, please request a warning light diagnostic.

GM Manufacturer Communication Number: 05-04-21-003 (TSB)
SERVICE 4WD LIGHT ILLUMINATED, DIAGNOSTIC TROUBLE CODE (DTC) C0374 SET. INSPECT WIRING HARNESS TO TRANSFER CASE SPEED SENSORS, REPLACE WIRING HARNESS.

GM Manufacturer Communication Number: 3137
SERVICE 4WD LIGHT ON AND NO COMMUNICATION WITH TRANSFER CASE CONTROL MODULE.

GM Manufacturer Communication Number: 3134B
SERVICE 4WD INDICATOR ILLUMINATED WITH DIAGNOSTIC TROUBLE CODE CO327.

GM Manufacturer Communication Number: 3352
SERVICE 4WD LIGHT ON WITH EITHER A VARIETY OF DIAGNOSTIC TROUBLE CODES OR NO COMMUNICATION WITH THE TRANSFER CASE CONTROL MODULE.

GM Manufacturer Communication Number: 3526
INTERMITTENT SERVICE 4WD LIGHT COMES ON WITH DIAGNOSTIC TROUBLE CODE (DTC) C0306 OR C0308 STORED IN TCCM.

While driving on freeway truck goes into a limp mode, and the check engine light, abs light, parking break light, service brake
ANSWER : It is possible that you could be having an issue with your powertrain control module. This is somewhat of a common problem on many GM vehicles. I would recommend having your vehicle inspected by the dealership to determine if the powertrain control module is functioning properly. If not, a reflash of the powertrain control module may resolve the issue but often times it must be replaced.

Abs light, emergency brake light, steering wheel assist light, engine light, EPC light, traction control light
ANSWER : Hello, thank you for writing in. The vehicle does utilize a lot of the same sensors for these systems. Are there any other codes that are coming up when this code appears? If so you will want to take these into consideration when processing the repair and making a diagnosis. The module may be bad, and replacing it should fix the problem. The lights should turn off once the main computer recognizes the new module and the sensors sync up. If you believe the sensors need to be cleaned you may do so. Do as minimal as possible to make sure you are not damaging the sensor or disrupting the wiring inside. A bad connection would make the lights stay on. With so many lights that are effected by the module being illuminated, the module is likely bad or does not have a connection. Check the connection first and then resort to replacing the unit. For more help with these electrical tests, contact our service department.

Loud repetitive noise coming from front tire in 2 wheel drive, goes away when in 4 wheel drive.
ANSWER : Hello, thank you for writing in. Chances are there was an existing issue that was amplified by the tire rotation. There are several parts that will cause similar symptoms. You will want to consider the parts that are under load in 4wd, that are free when in 2wd. This would include the axle and sveral joints. There are a couple of tests that can be done. More damage was likely done driving on dry pavement in 4wd. It was a good step in diagnostics, but should be avoided. For more help with diagnosing the sounds, contact our service department to schedule an appointment.

Turn selector switch to 2 Wheel Dr. and it stays in four-wheel-drive and then yellow light comes on on the dash and says service
ANSWER : Hello, thank you for writing in. The vehicle is equipped with an electric transfer case, in which something has gone wrong. The fact your are stuck in 4WD, is because the computers programming demands the system shuts down during this time. You will want to have the vehicle scanned for diagnostic codes to find out what about the system is failing. The codes can be removed to try and temporarily switch back to 2WD. Be careful with this, as shutting down the system when there is a fault is a safety matter. For more help with diagnostics, contact our service department to schedule an appointment.

Why is my 4-wheel drive engaging while I’m driving?
ANSWER : Hey there. Driving with 4×4 on when it is not needed can be rough on the axles, transmission, and hubs. The 4×4 engaging on its own can be the result of a mechanical error or an electrical error.

Mechanically if there is a vacuum leak in the system that engages the 4×4, the hubs can engage automatically if the wheels are rolling. There are other standards that need to be met for this to happen, which is why it is happening under certain conditions. There are a set of vacuum lines that run next to the battery that may need to be replaced.

There are several electrical components that have an effect on the system as well. Any issues like that would likely show on a diagnostic code scan.

If you would like to have this resolved, a certified technician from YourMechanic can come to your car’s location to inspect the transmission and advice you any corrections needed.

4 wheel drive icon is staying on
ANSWER : If the switch for your four wheel drive has broken and your vehicle is now stuck in four wheel drive, it is very likely that the broken switch is the cause of your issue. I would recommend having this switch replaced to see if these symptoms go away. The reason the vehicle is harder to turn is due to the four wheel drive being engaged. This should also go away once the switch has been replaced. Consider YourMechanic for this switch replacement as it can be completed at your home or office.