HD Fault codes

[Guns]

I get asked regularly, how to find out what an engine diagnostic code is and how to find them so here is some info straight from the horses mouth so to speak:

DIAGNOSTIC MODE
The diagnostic mode is entered by turning the ignition from OFF to ON while holding the reset switch in.
The normal power-up sequence will occur before entering the diagnostic mode.
Diagnostic codes set during this power-up sequence will be stored as well.

IMPORTANT NOTE
Be sure no diagnostic codes are indicated before reset is held in for more than 5 seconds or diagnostic information will be lost.
When in the diagnostic mode the odometer will display the first diagnostic code.
When the trip switch is pressed again the next code will be shown.
If the trip switch is pressed for more than 5 seconds at any time while in the diagnostic mode, all of the diagnostic codes will be erased whether they have been displayed or not.
See table below.

There are 7 different diagnostic codes available.
When in the diagnostic mode, all codes are displayed in sequence from d01 to d10.
As a code appears in the display (for instance d02), it will read "d02SEt" if set or "d02CLr" if clear.
The diagnostic mode is exited either by turning ignition from ON to OFF to ON again without depressing the reset switch or if a speed signal greater than 5 MPH is detected.

Diagnostics cannot be performed if system voltage is less than 9 VDC or greater than 16VDC. The only exception is d08 which is set when system voltage is greater than 16VDC.
After all the diagnostic codes are displayed, the speedometer's pulses per unit setting is displayed. This number will vary depending on speedometer part number.

SPEEDOMETER TROUBLE CODES

CODE - TROUBLE - WIRE COLOR
d01 - speed sensor power output shorted low - red
d02 - speed sensor power output shorted high - red
d03 - not used
d04 - not used
d05 - speed sensor return shorted high - white
d06 - speed sensor return shorted low - white
d07 - not used
d08 - speedometer power overvoltage - orange/white
d09 - speed output shorted high - white/green
d10 - speed output shorted low or open - white/green
5 digit number - speedometer pulses per unit

Hope this helps

Guns