Rick's Free Auto Repair Advice

Service 4WD Light on Dodge Ram

Service 4WD Light on Dodge Ram

Chrysler has issued a service bulletin #21-005-12 to address a service 4WD light on Dodge Ram on the vehicles listed below. In addition to the service 4WD light on service 4WD Dodge RamDodge Ram, owners may also have a C2201 -FDCM/DTCM Internal diagnostic trouble code.

This bulletin applies to the following vehicles:


2011 – 2012 RAM 1500 Pickup

2012 RAM 3500 Pickup

2012 RAM 3500 Cab Chassis

2012 RAM 2500 Pickup

2012 RAM 4500/5500 Cab Chassis

2011 – 2012 RAM Regular Cab Chassis (Mexico)


The bulletin applies ONLY to vehicles with an electronic transfer case (sales code DH8, DH9 or DK3) built before January 6, 2012 (MDH 0106XX).


When the Service 4WD light comes on, it also shuts down the 4WD capability for the remainder of the drive cycle. This is a software issue and can only be corrected by flashing the computer’s memory.


Re-flashing can be done at the dealer or at an independent repair shop equipped with reprogramming equipment. Reprogramming is NOT free. Plan of a service charge of around $200 to bring your software up to date.


©, 2015 Rick Muscoplat

Posted on by Rick Muscoplat

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