Diagnostic Test Mode Codes (With Machine OFF)

The diagnostic test mode is used to check the integrity of the switches, sensors, wiring, and hardware of the control module. Diagnostic information is generated in the control module and displayed through a flashing code on the diagnostic indicator light.

Before entering the Diagnostic Test Mode, place all switches and controls in the following positions:

• Key switch - RUN
• PTO switch - OFF
• Park brake - DISENGAGED
• Operator seat - NOT OCCUPIED
• Motion control levers - NEUTRAL
• Deck lift switch - RELEASED
• PTO STOP thumb switch - DEPRESSED

Enter the diagnostic test mode by quickly cycling the key switch from OFF to RUN three times. On the third cycle leave the key in the RUN mode.

NOTE: Do not rotate the key past RUN to START mode during these three cycles.

In the test mode, the control module will not permit engine and PTO operation. The control module will automatically exit the test mode if no activity occurs for ten minutes.

Upon entering the Diagnostic Test Mode, the control module will perform an automatic diagnostic check. If there are no problems detected, the display will flash a 1-1 Code.

If a problem is detected, the display will flash one or more codes to indicate which circuit is affected. See the chart below for instructions on how to remove the fault codes detected and achieve a 1-1 code display.

Diagnostic Test Mode Code	Fault Code Description	Action Needed to Remove Unwanted Codes:
3 - 1	Battery Voltage High	Inspect electrical harness for loose connections, specifically the battery positive and negative, the starter, and frame ground (on engine block).
3 - 2	Battery Voltage Low	• Check battery, starter, and ground connections. • Check charging system connections.
1 - 2	Key Switch in START Position	Place key switch in RUN position.
1 - 3	PTO Switch ON	Turn PTO switch OFF.
1 - 4	Brake Switch ON	Release brake.
1 - 5	Seat Switch DEPRESSED	De-activate seat switch (operator not in seat).
1 - 6	Motion Levers Not in NEUTRAL	Place both levers in NEUTRAL position.
1 - 8	Deck Lift Switch ON	Release the left lever arm button (black) switch.
1 - 9	PTO Stop Switch RELEASED	Depress the right lever arm button (yellow) switch.
2 - 2	Over Temp Switch ON	See the Technical Manual or your John Deere Dealer for additional information.
1 - 1	All is Well	See the chart below for addition diagnostic instructions.

Once the 1-1 Code has been achieved, the following steps should be performed (in any order) to verify the electrical function of each individual switch in the control module system.

• Release the PTO STOP yellow button on the right lever arm. The 1-9 code should flash. Depress the PTO STOP button.
• Turn the key switch to the START position. The 1-2 Code should flash. Return to RUN position.
• Pull the knob to activate the PTO switch. The 1-3 code should flash. Return PTO to OFF position.
• Depress the brake pedal. The 1-4 code should flash. Release the pedal.
• Sit on seat to activate the seat switch. The 1-5 code should flash. Get out of the seat.
• Individually move each motion control lever from the neutral position. The 1-6 code should flash for each lever. Place both levers in the NEUTRAL position.
• Push the black button on the left lever arm to activate the deck lift switch. The 1-8 Code should flash. Release the deck lift button.

If any of the Diagnostic Test Mode Codes are not displayed in the steps listed above, inspect the applicable wiring harness connections and switch, or contact your John Deere Dealer for further assistance or part replacement.