2005-2008 Honda ATV TRX500FA/FGA Fourtrax, Rubicon Factory Service Manual, Page 470Get this manual
SELECTABLE 4WD SYSTEM
BEFORE STARTING TROUBLESHOOTING
SELF-DIAGNOSTIC FUNCTION
The engine control module (ECM) that controls the Selectable 4WD system has self-diagnostic function to constantly monitor the systemThe ECM checks the condition of the Selectable 4WD system by detecting the signals from each sensor and device when the ignition switch is ON and during drivingWhen the ECM detects problem in the system, the ECM overrides the 4WD selector switch, puts the machine into 2WD, and 4WD cannot be used When the ECM detects problem, it indicates the problem by blinking the 4WD indicatorNote how many times the indicator blinks, determine the detection item (page 23-4) and perform the troubleshooting (page 23-5) Only one current problem code will be indicated even if two or more problems occur Once the ECM detects problem, it stores the problem code in the erasable memoryIt can be indicated as freeze code by retrieval of problem code (Retrieval and erasure procedure are the same as the Hondamatic ones, refer to page 249) The selectable 4WD function can be reset by turning the ignition switch OFF and ON, but the 4WD selector stops functioning when the ECM detects the problem again After performing troubleshooting, erase the problem code(s) and test-drive the vehicle to be sure that the problem(s) hashave been repaired4WD INDICATOR