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John Deere 3120, 3320, 3520, 3720 - Troubleshooting and Error Codes

JD 3120, 3320, 3520, 3720 Engine

1) Engine Will Not Crank - PowrReverser: Transmission gear shift lever not in neutral position. PTO engaged. Battery low on charge. Blown fuse. Electrical problem.

2) Engine Will Not Start - Wrong engine oil viscosity. Engine hand throttle lever not pushed forward. Cold start system not being used, or malfunctioning. Stale fuel / improper fuel / fuel level. Plugged fuel filter. Dirty or faulty fuel injectors. Failed fuel solenoid.

3) Engine Runs Rough Or Stalls - Engine hand throttle lever not pushed forward. Plugged fuel filter. Plugged air intake system. Fuel cap vent dirty. Faulty seat switch. Stale or improper fuel / fuel level / water in fuel. Dirty or faulty fuel injectors. Low coolant temperature. Fuel pump not functioning properly.

4) Engine Knocks - Engine oil level low. Low coolant temperature. Engine overheating. Idle speed too slow. Faulty cold advance device.

5) John Deere 3120, 3320, 3520, 3720 Engine Overheats - Low coolant level. Cooling system needs flushing. Defective radiator cap. Defective thermostat. Defective water temperature indicator or sender. Low oil level. Loose or defective alternator belt. Do not operate at slow idle, operate at fast idle. Dirty grille, radiator screen, or radiator cooling fins. Operating at too fast ground speed for conditions.

6) Engine Lacks Power - Brakes dragging. Misadjusted rockshaft feedback linkage. Improper type of fuel. Plugged air intake system. Plugged fuel filter. Engine overheating. Operating at too fast ground speed for conditions. Engine oil viscosity too high. Low coolant temperature. Dirty or faulty fuel injectors. Dirty intercooler fins. Implement improperly adjusted. See implement operator’s manual. Improper ballast - adjust load. Rockshaft stop valve closed. Turbo housing hose leaks.

7) Low Oil Pressure - Engine oil level low. Plugged oil filter. Improper type of oil. Faulty pressure regulating valve.

8) Engine Uses Too Much Oil - Find and correct oil leaks. Incorrect engine oil. Plugged air intake filter.

9) Engine Emits White Smoke - Improper type of fuel. Low engine temperature. Defective thermostat. Faulty cold advance device.

10) Engine Emits Black Or Gray Exhaust Smoke - Improper type of fuel. Plugged air intake system. Operating at too fast ground speed for conditions. Dirty or faulty fuel injectors. Dirty intercooler fins.

11) High Fuel Consumption - Improper type of fuel. Plugged air intake system. Operating at too fast ground speed for conditions. Dirty or faulty fuel injectors. Implement improperly adjusted, causing drag on machine. See implement operator’s manual. Plugged crankcase vent tube or baffle. Brakes dragging.

John Deere 3120, 3320, 3520, 3720 Electrical System

1) Battery Will Not Charge - Loose or corroded connections. Defective battery. Dead cell in battery. Loose or defective alternator belt. Defective alternator. Check 3 pin connector on alternator is plugged in properly.

2) Battery Discharge Indicator Stays On With Engine Running - Low engine speed. Defective battery. Defective alternator. Loose or defective alternator belt. Check 3 pin connector on alternator is plugged in properly.

3) Starter Will Not Work - Loose or corroded battery connections. Blown fuse. Starter solenoid connector pulled off or corroded. Low battery power. Neutral start switch faulty. Key switch or starter faulty. PowrReverser: Transmission gear shift lever not in proper position. PTO engaged or faulty switch. Neutral start switch jumper defective (eHydro only).

4) Starter Turns Slowly - Low battery power - charge battery. Engine oil viscosity too heavy. Loose or corroded battery connections.

5) Cab Window wiper(s) and washer will not run - Blown fuse. Faulty wiring or loose connections. Defective switch(es). Defective motor(s). Cab Work lights do not work - Blown fuse. Faulty wiring or loose connections. Defective bulb or switch. Replace bulb.

6) Cab Dome light does not work - Blown fuse. Faulty wiring or loose connections. Defective bulb or switch. Replace bulb. Defective door switch(es).

John Deere 3120, 3320, 3520, 3720 Heater and Air Conditioning System

1) All cab electrical switches do not work - Loose, defective or blown fusible link.

2) Blower malfunctioning - Blown fuses. Blower does not work.

3) Blower operates only in high position - One of two fuses blown. Blown blower resistance assembly.

4) Heater does not work - Low coolant level. Check coolant level; add if necessary. Faulty thermostat. Heater control valve not functioning properly. Heater core or hoses clogged or damaged. Flush cooling system. Replace heater core or hoses.

5) Air conditioning does not work - Blown fuse. Faulty wiring or loose connections. Fan belt loose or slipping. Defective switch. Defective compressor clutch.

6) Drafts - Poor air distribution. Adjust directional air louvers. Set blower switch to medium or low positions.

7) Inadequate air flow - Clogged air filters. Evaporator core air flow restricted. Faulty blower fan motors. Defective blower switch. Faulty wiring or loose connections.

8) Water leaking or dripping from evaporator core compartment - Loose hose clamp. Evaporator condenser pan dirty. A/C drain tubes plugged.

9) Strange odors inside operator’s cab - Dirty air filters. Evaporator condenser pan dirty. A/C drain tubes plugged. Tobacco smoke and tar on evaporator exterior.

10) Partial frosting and sweating of lines combined with poor cooling - Fan belt slipping. Loss of refrigerant. Restricted or clogged liquid line. Expansion valve malfunctioning.

11) Ice flecks blowing from evaporator - Control dial set too low. Adjust temperature control to a warmer position.

12) Failure to cool - Insufficient blower speed. Dirty air filters. Debris on front grille. Lint or dirt on condenser fins. Refrigerant is lost or extremely low. Loose fan belt. Compressor clutch not engaging. Expansion valve not functioning. Restriction in refrigerant system. Faulty wiring or loose connections. Defective temperature control switch. Outside temperature too low, below 21gets warmer. Condenser is overheating. Clean condenser screens, cores and fins of condenser and radiator. Severe restriction in high side. Burned out clutch field or faulty field. Short circuit in control circuit or failure of a switch in circuit.

13) Hissing noise at expansion valve - Loss of refrigerant. Restriction in refrigerant system. Check receiver-dryer for uniformity of temperature.

JD 3120, 3320, 3520, 3720 Machine

1) Operation Sluggish, Slow - Suction side filter may need replacement.

2) Poor Hydraulic Performance - Suction side filter may need replacement. Water in oil.

3) Excessive Machine Vibration - Engine speed too slow. Throttle linkage out of adjustment.

4) Machine Will Not Move With Engine Running - Electrical problems. Operator pushing down both travel pedals at same time. Park brake locked. Transmission oil level low. Transmission oil cold - allow engine to warm. Transmission range shift lever in neutral position. Suction side filter may need replacement. Operator not in seat.

5) 3-point Hitch Fails To Lift - Low oil level. Worn hydraulic pump. Rate of drop valve closed. Excessive load on hitch. Hydraulic oil too cold. Hydraulic oil suction filter plugged.

6) 3-point Hitch Lifts Slowly - Suction side filter may need replacement. Worn hydraulic pump.

7) 3-point Hitch Drops Slowly Or Does Not Drop - Rate-of-drop valve closed. Rate-of-drop valve set too slowly.

8) 3-point Hitch Drops Too Fast - Rate-of-drop set too fast. Load too heavy.

Steering and Brakes

1) Rear Wheel Brakes Not Working - Brakes out of adjustment. Worn or damaged brake linkage.

2) Steering Not Working - Hydraulic suction filter plugged. Improper tire inflation. Steering linkage needs lubrication. Excessive play in steering.

JD 3120, 3320, 3520, 3720 Error Codes

Err 01 - Forward and reverse pedals. Both pedals are depressed. Machine does not drive. Release both pedals and depress one at a time.

Err 02 - Forward Pedal. Voltage signal out-of-range or not calibrated. Machine does not drive.

Err 03 - Reverse Pedal. Voltage signal out-of-range or not calibrated. Machine does not drive.

Err 04 - Engine Speed. No signal at Engine Speed input. No anti-stall or cruise functions; Loss of performance.

Err 05 - Brake and Cruise Set/Decel Switch. Cruise control Set/Decel switch depressed while brake is engaged. No cruise function. Release brake pedal.

Err 06 - MFWD Speed. No signal at MFWD speed input. No cruise function; Loss of performance.

Err 07 - Cruise Set/Decel Switch. Cruise Set/Decel switch is held or stuck on. No cruise function.

Err 08 - Throttle Sensor. Voltage signal out-of-range or not calibrated. No anti-stall function; Loss of performance.

Err 09 - Cruise On/Off and Set Max Speed switches. Cruise and Max Speed inputs are both active. No cruise function.

Err 11 - Cruise Set/Decel and Cruise Res/Accel switches. Set/Decel and Resume/Accel switches are both active. No cruise function.

Err 12 - Sensor Supply voltage. Voltage is out-of-range. Machine does not drive.

Err 14 - Pump Current. Coil resistance too high (open) or too low (short). Machine does not drive.

Err 15 - Operator Present. Operator not in the seat. Machine does not drive. Return back to the seat.

Err 57 - HST Timeout. No response from HST controller. Loss of features.

Err 60 - Right Red Lamp ON. Output from the Display is short circuit. No right turn signal on the ROPS. Check the right red lamp.

Err 61 - Right Red Lamp OFF. Output from the Display is open. No right turn signal on the ROPS. Check the right red lamp.

Err 62 - Left Red Lamp ON. Output from the Display is short circuit. No left turn signal on the ROPS. Check the left red lamp.

Err 63 - Left Red Lamp OFF. Output from the Display is open. No left turn signal on the ROPS. Check the left red lamp.

Err 64 - Right Amber Lamp ON. Output from the Display is short circuit. No right hazard signal on the ROPS.

Err 65 - Right Amber Lamp OFF. Output from the Display is open. No right hazard signal on the ROPS. Check the right amber lamp.

Err 66 - Left Amber Lamp ON. Output from the Display is short circuit. No left hazard signal on the ROPS. Check the left amber lamp.

Err 67 - Left Amber Lamp OFF. Output from the Display is open. No left hazard signal on the ROPS. Check the left amber lamp.

Err 68 - Hold-in Relay ON. Output from the Display is short circuit. No fuel to the engine.

Err 69 - Hold-in Relay OFF. Output from the Display is open. No fuel to the engine.

Err 70 - Starter Relay ON. Output from the Display is short circuit. Can not crank the engine.

Err 71 - Starter Relay OFF. Output from the Display is open. Can not crank the engine.

Err 72 - Display Mode Switch. The LCD Display Mode/Configuration input is stuck on. No other info selectable; No HST commands selectable.