Troubleshooting

Using Troubleshooting Chart

If you are experiencing a problem that is not listed in this chart, see your authorized dealer for service.

When you have checked all the possible causes listed and you are still experiencing the problem, see your authorized dealer.

Engine


If	Check
Engine Will Not Start Or Is Hard To Start	• Park brake unlocked or not adjusted correctly. • Key switch not in proper position. • Stale or improper fuel / fuel level • Plugged fuel filter. • Plugged air intake filter. • Spark plug wire is loose or disconnected. • Spark plug not gapped correctly. • Blown fuse. • Electrical problem - dead battery. • Choke adjusted incorrectly. See your John Deere dealer.
Engine Will Not Slow Idle	• Carburetion problems. See your John Deere dealer. • Bent or kinked throttle cable. • Bent governor control. • Incorrect governor idle control.
Engine Runs Rough or Stalls	• Plugged fuel filter. • Plugged air intake system. • Fuel cap vent dirty. • Stale or improper fuel / fuel level. • Spark plug not gapped correctly. • Replace spark plug. • Choke adjusted incorrectly. See your John Deere Dealer.
Engine Knocks	• Engine oil level low. • Reduce load. (Slower ground speed.) • Fuel is bad. Fill tank with fresh fuel, correct octane. • Idle speed too slow.
Engine Overheats	• Clean cooling fins. • Low oil level. • Do not operate at slow idle. Operate at fast idle. • Cooling air intake screen is dirty. • Plugged air intake filter. • Operating at too fast ground speed for conditions.
Engine Lacks Power	• Plugged air intake system. • Plugged fuel filter. • Improper type of fuel. Drain tank and fill with correct fuel. • Clean cooling fins to help prevent overheating. • Replace spark plug.
Engine Uses Too Much Oil	• Find and correct oil leaks. • Incorrect engine oil. • Plugged oil filter. • Plugged air intake filter.
Engine Backfires Through Muffler	• Throttle should be set at 1/2 throttle before turning off machine.
High Fuel Consumption	• Improper type of fuel. • Plugged air intake system. • Operating at too fast ground speed for conditions. • Improper valve clearance. See your John Deere Dealer. • Restricted air intake system.

Electrical System


If	Check
Starter Will Not Work	• Blown fuse. • Loose or corroded battery or ground connections. • Loose harness or ground connections to starter. • Park brake switch faulty or not adjusted properly. (See your John Deere Dealer) • Key switch or starter faulty. (See your John Deere Dealer) • Park brake pedal not in proper position. • Low battery power - charge battery.
Battery Will Not Charge	• Loose or corroded battery or ground connections. • Dead cell in battery.
PTO Switch Does Not Work	• Blown fuse • Bad switch. • Bad clutch. • Failed regulator/rectifier. • Loose PTO clutch or switch connections. • Loose harness or ground connections.
Starter Turns Slowly	• Loose or corroded battery or ground connections. • Low battery power - charge battery. • Engine oil viscosity too heavy. • Transmission linkage adjustment problem or failure.

Diagnostic Real-Time Codes

NOTE: For further assistance with all Diagnostic Codes, refer to the Technical Manual and/or consult your John Deere dealer.


Electrical System “Interlock” Violations
Real-Time Diagnostic Trouble Code Description	Diagnostic Code	Notes	Action Required to Remove Code:
Brake Not Locked	1 - 2	This code can occur under the following conditions: 1. When the engine is trying to be started without the brake pedal locked. NOTE: Machine will automatically shut down if the following occurs. 2. When the engine is running and operator gets out of seat without the brake locked.	• Verify the Park brake pedal is locked.
PTO/Mow Engaged	1 - 3	NOTE: This will cause the PTO to be disabled. • This code will occur only when getting out of the seat while operating the machine with the PTO engaged.	NOTE: For Safety, the PTO can not be engaged with the park brake locked or with the operator out of the seat. • Turn key switch to the OFF position.
Crank Time Exceeded (20 second limit)	2 - 4	This code will let the operator know the maximum cranking time of 20 seconds per crank has been exceeded.	• Return the key to the OFF or RUN position.
Starter Thermal Protect Mode, 60-second Cool-Down Needed	2 - 5	This code indicates that the module has started a 60-second cool-down period to prevent the starter from overheating.	• Turn the key switch to the OFF position and let the starter cool down for at least 60 seconds before making another attempt to start the engine.
Engine Over Temp, (PTO disabled). • 840A machines	2 - 6	This code indicates that the engine has exceeded the maximum operating temperature range. The engine will shut down and the PTO will be disabled.	• Turn key switch to OFF position and let the engine cool down before making another attempt to start the engine. • To ensure that the engine does not continue to overheat, determine the cause. Refer to Troubleshooting - Engine section.


Electrical System 'Fault' Violations
NOTE: For All “Fault” codes it is important to first check battery, starter, and ground connections. • Codes and instructions as follows.
Electrical System Diagnostic Trouble Code Description	Diagnostic Code	Notes	Action Required to Remove Code:
Over Voltage	3 - 1	This code indicates that the electronic control module has detected a voltage higher than normal in the electrical charging system.	• Inspect the electrical harness for loose connections, specifically the battery positive and negative, starter, and frame ground (on engine block).
Low Voltage	3 - 2	This code will let the operator know that the battery is being depleted.	• Check charging system connections.
Weak Battery OR Starter System Issue	3 - 3	This code indicates that the battery may have become too weak to turn the starter or that the electronic control module has detected an excessive current draw.	• Recharge the battery. • Check starter system connections and harness wiring.
Starter Output Short to Battery	3 - 4	This code indicates that there is a short in the starter circuit to the battery.	• Inspect electrical harness for pinched, chafed, or frayed wires.
PTO Output Over-Current	3 - 5	This code indicates that there is excessive current through the PTO circuit.	• Inspect electrical harness for pinched, chafed, or frayed wires.
PTO Output Shorted to Battery	3 - 6	This code indicates that there is an electrical short in the PTO circuit to the battery	• Inspect harness for pinched or chafed wires.
Output Fault Detected	3 - 7	This code indicates that the electronic control module has detected an electrical problem in the engine wiring harness and the control module’s internal re-settable fuse has tripped to protect the system.	• Inspect engine harness for pinched or chafed wires.

Diagnostic Test Mode Codes (With Machine OFF)

This 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 display module (next to the wrench icon).

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

Before entering the Diagnostic Test Mode, it is best to turn off all switch INPUTS (i.e., brake not locked, PTO switch not in the on position, operator not in seat, etc.). Once all the INPUTS are off, the operator can enter the Diagnostic Test Mode by cycling the key switch quickly from OFF to RUN exactly three times. On the third cycle leave the key in the RUN mode.

Upon entering the Diagnostic Test Mode, the control module will perform an automatic diagnostic check. If there are no system FAULTS and all the INPUTS are not detected, the display will flash a 1-1 Code.

See the chart below for instructions on how to remove the Fault/Input Codes in order to achieve a 1-1 Display.


Diagnostic Test Mode Code	Fault/Input Code Description	Action Needed to Remove Unwanted Codes:
3 - 7	Control Module’s INTERNAL Resettable Fuse Tripped	• Inspect battery, starter, and ground connections. • Inspect engine harness for pinched or chafed wires.
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 to START	Verify key switch is in RUN mode not START.
1 - 3	PTO (Knob) Switch Input ON	Turn OFF switch (knob in the down position).
1 - 4	Brake Switch Input ON	Unlock the brake pedal, check brake switch for engagement.
1 - 5	Seat Switch Input ON	De-activate seat switch (operator not in seat).
1 - 8	Deck Lift Switch Input ON	Release the left lever arm button (black) switch.
1 - 9	PTO Stop Switch ON	Release the right lever arm button (yellow) switch.

Once the 1-1 Code has been achieved, the following steps should be performed to complete the Diagnostic Test Mode INPUT CHECKS in order to verify electrical functionality for code.


Actions Required to Verify Electrical Functionality Note: INPUT actions can be performed in any order.	INPUT Description	Diagnostic Test Mode Code
Turn the KEYSWITCH to the START position. The 1-2 Code should flash. Return to RUN position.	Key switch to START	1 - 2
Pull the knob to activate the PTO switch. The 1-3 code should flash. Return PTO to OFF position.	PTO (Knob) Switch Input ON	1 - 3
Activate the BRAKE pedal. The 1-4 code should flash. De-activate the pedal.	Brake Switch Input ON	1 - 4
Sit on seat to activate the SEAT switch. The 1-5 code will should flash. Get out of the seat.	Seat Switch Input ON	1 - 5
Push the black button on the left lever arm to activate the DECK LIFT switch. The 1-8 Code should flash. Release the button.	Deck Lift Switch Input ON	1 - 8
Push the yellow button on the right lever arm to activate the PTO STOP switch	PTO Stop Switch ON	1 - 9

If the Diagnostic Test Mode Codes cannot be achieved when applying the INPUT Actions listed above, inspect the applicable wiring harness connections and switch, or contact your local John Deere Dealer for further assistance or part replacement.

Machine


If	Check
Excessive Machine Vibration	• Engine speed too slow.
Machine Will Not Move With Engine Running	• Park brake locked. • Transmission hydraulic oil level low. • Transmission oil cold - allow engine to warm. • Drive belt slipping or broken. • Bypass pump release valves open. • Traction drive belt damaged or worn. • Transmission problems. See your John Deere Dealer.
Machine Creeps With Engine Running and Motion Control Levers in a Neutral Position	• Check and adjust neutral creep.

Brakes


If	Check
Machine levers are adequately locked in neutral when the park brake is engaged, but the machine creeps.	Check and adjust neutral creep. See Park Brake Adjustment. Check and secure cables and hardware.
Machine levers have excessive fore-aft movement with the park brake engaged.	Check and align motion control levers. Check control levers for loose hardware or excessive wear.
Machine levers are adequately locked in neutral, and no creep exists, but the brake pedal will not fully release due to binding in the system.	Back out neutral interlock adjustment set screws 1 flat and re-check system for binding. Add grease to neutral interlock cam. Check and align motion control levers.
Control levers rub/contact slots in the frame when moved to “out” position.	Check and align motion control levers.
Brake pedal difficult to engage.	Check and align motion control levers. Add grease to neutral interlock cam.
Brake switch not engaging/disengaging	Check and align motion control levers.

Steering


If	Check
Steering Not Working	• Bypass pump release valves partially open. • Improper tire Inflation. • Hydrostatic transmission oil low.

Mower


If	Check
Discharge Chute Plugged	• Grass is wet - ground speed may need to be adjusted. • Raise cutting height. • Run engine at fast idle. • Ground speed too fast for conditions. • Correct installation of deck drive belt.
Mower Deck Vibrates	• Run engine at fast throttle. • Loose hardware. • Check/replace deck drive belt. • Blade bolts are loose. • Blades are bent or worn. • Sharpen and balance blades. • Remove belt shields and clean debris from sheaves. • Check sheaves for proper alignment or damage. See a John Deere dealer.
Mower Blades Do Not Engage	• Deck drive belt slipping or broken, check and adjust belt tension. • Deck belt tension spring not installed or broken. • PTO switch failure. • Fuse is blown. • Loose electrical connections.
Mower Mows Unevenly	• Mower deck not properly leveled. • Ground speed too fast for conditions. • Run engine at fast throttle. • Reduce ground speed when making turns. • Sharpen or replace blades. • Change mowing pattern. • Check air pressure in all traction unit tires.
Poor Quality Cut	• Clean debris build-up from underside of deck. • Check blades for sharpness and damage. • Check discharge chute for damage. • Change blades. • Run engine at fast throttle.