Central Control Unit (CCU) Diagnostic Codes

Symptom Problem Solution

CODE CCU 1

Fuel level input open circuit or shorted

Have your John Deere Dealer repair at earliest convenience

CODE CCU 4

Fuel flow signal missing (Warning)

Fill fuel tank (See Fuels, Lubricants and Coolant Section)

Have your John Deere Dealer check injection system as soon as possible

CODE CCU 5

Engine oil pressure input sensor is out of range low.

Have your John Deere Dealer repair at earliest convenience

CODE CCU 6

No communication from Engine Control Unit (ECU)

Have your John Deere Dealer repair at earliest convenience

CODE CCU 7

ECU does not match tractor model

Have your John Deere Dealer repair as soon as possible

CODE CCU 9

Seat switch stuck closed

Have your John Deere Dealer repair at earliest convenience

CODE CCU 10

Coolant temperature high (Warning)

Check coolant level, fan belt, and radiator and hoses for leaks

Clean grille, side shields, radiator and oil cooler

Reduce load or shift to lower gear

CODE CCU 11

Coolant temperature high (STOP ENGINE)

Check coolant level, fan belt, and radiator and hoses for leaks

Clean grille, side shields, radiator and oil cooler

Reduce load or shift to lower gear

CODE CCU 12, 13

Coolant temperature input open circuit or shorted

Have your John Deere Dealer repair at earliest convenience

CODE CCU 15

Hydraulic oil temperature high (Warning)

Check oil level and filter

Clean grille, side shields, radiator and oil cooler

AG,RX15494,374 -19-22MAR99-1/5


Symptom Problem Solution

CODE CCU 16

Hydraulic oil temperature high (STOP ENGINE)

Check oil level and filter

Clean grille, side shields, radiator and oil cooler

CODE CCU 17, 18

Hydraulic oil temperature input open circuit or shorted

Have your John Deere Dealer repair as soon as possible

CODE CCU 19

Hydraulic oil temperature low (throttle speed limited)

Run tractor at idle speed until oil warms up or warm transmission/hydraulic oil (See Transmission-Hydraulic System Warm-Up in Operating the Tractor Section)

CODE CCU 20

Engine oil pressure low (STOP ENGINE)

Check oil level

Incorrect type of oil

Drain, fill crankcase with correct oil (See Engine Oil in Fuels, Lubricants and Coolant Section)

CODE CCU 23

Engine speed signal missing

Have your John Deere Dealer repair at earliest convenience

CODE CCU 24

Hydraulic oil reservoir level switch open circuit

Have your John Deere Dealer repair as soon as possible

CODE CCU 25

Transmission oil pressure switch open circuit

Have your John Deere Dealer repair at earliest convenience.

CODE CCU 26

Transmission oil pressure low (STOP ENGINE)

Check transmission oil level and filter

CODE CCU 29

Axle lube pressure switch open circuit

Have your John Deere Dealer repair at earliest convenience

CODE CCU 30

Engine air filter restricted (Warning)

Clean or replace filter (See Service Air Cleaner in Service/As Required Section)

AG,RX15494,374 -19-22MAR99-2/5


Symptom Problem Solution

CODE CCU 45, 46

Low voltage or excessive electrical load (Warning)

Check battery (See Service Batteries in Service/250 Hours Section)

Check belt tensioner (See Check Belt Tensioner in Service/1500 Hours Section)

Reduce electrical load

Have your John Deere Dealer check charging system

CODE CCU 47

High voltage (Warning)

Replace voltage regulator

Have your John Deere Dealer check charging system

CODE CCU 49

High voltage (STOP ENGINE)

Replace voltage regulator

Have your John Deere Dealer check charging system as soon as possible

CODE CCU 50

Hydraulic oil filter restricted (Warning)

Change transmission/hydraulic oil filter

CODE CCU 51

Transmission oil filter restricted (Warning)

Change transmission oil filter

CODE CCU 52

PST front axle filter restricted (Warning)

Change axle oil filter

CODE CCU 53

Transmission Hi-Lo solenoid circuit-24-Speed (Warning)

If operating Hi-Lo in Lo, bump shift to Hi

CODE CCU 61

Hydraulic oil reservoir level low (STOP ENGINE)

Add transmission/hydraulic oil (See Check Transmission/Hydraulic Oil Level in Service/Daily or Every 10 Hours Section)

CODE CCU 64

Axle lube pressure low (STOP ENGINE)

Add transmission/hydraulic oil (See Check Axle Oil Level in Service/Daily or Every 10 Hours Section)

AG,RX15494,374 -19-22MAR99-3/5


Symptom Problem Solution

CODE CCU 65

Axle lube pressure low (Warning)

Add transmission/hydraulic oil (See Check Axle Oil Level in Service/Daily or Every 10 Hours Section)

Run engine with transmission in Park/Neutral at 2100 rpm at least 5 minutes to warm oil

CODE CCU 67

Electrical sensor or circuit

Check fuse F14 (See Load Center Fuses in Service/As Required Section)

Have your John Deere Dealer repair as soon as possible

CODE CCU 70

Operator out of seat with PTO engaged (Warning)

If not stationary PTO use, return to seat or turn off PTO before leaving cab (See Operator Presence Sensor in Operator Station Section)

CODE CCU 80

Differential lock on at start-up

Operate switch (See Using Differential Lock in Operating the Tractor Section)

Have your John Deere Dealer repair at earliest convenience, if light remains on

CODE CCU 81

Differential lock disabled, circuit failure

Have your John Deere Dealer repair at earliest convenience

CODE CCU 88

PST oil temperature high (Warning)

Check oil level and filter

CODE CCU 89

PST oil temperature high (STOP ENGINE)

Check oil level and filter

CODE CCU 90, 91

PST oil temperature sensor open circuit or shorted

Have your John Deere Dealer repair as soon as possible

CODE CCU 95

Hand throttle command missing (Warning)

Check fuse F3

Have your John Deere Dealer repair as soon as possible

AG,RX15494,374 -19-22MAR99-4/5


Symptom Problem Solution

CODE CCU 101

Axle lube pressure switch failed closed

Have your John Deere Dealer repair at earliest convenience

CODE CCU 120, 121, 122, 125

Controller fault

Have your John Deere Dealer repair as soon as possible

AG,RX15494,374 -19-22MAR99-5/5