SSU Control Unit – The SSU (Steering System Control Unit) is responsible for controlling the AutoTrac automatic steering system.
John Deere SSU fault codes / John Deere SSU diagnostic trouble codes
NOTE:This page only indicates the meaning of the fault codes. For complete troubleshooting information, see the technical manuals.
SSU 000084.09 (SSU 84.09)— Incorrect CAN BUS Message, Travel Speed from BCU
This diagnostic trouble code is generated if no signal from the travel speed sending unit can be detected on the CAN BUS.
SSU 000162.09 (SSU 162.09)— Incorrect CAN BUS Message, Transmission Type from EPC or TCU
If the information on transmission type (entry in address SSU 036) is not recognized on the CAN BUS after four attempts, this diagnostic trouble code is generated. This indicates a problem with the CAN BUS.
SSU 000168.03 (SSU 168.03)— Supply Voltage Too High
If battery voltage rises above 16 volts for longer than 320 ms, this diagnostic trouble code is triggered.
SSU 000168.04 (SSU 168.04)— Supply Voltage Too Low
If battery voltage drops below 9 volts for longer than 320 ms, this diagnostic trouble code is triggered.
SSU 000177.09 (SSU 177.09)— Incorrect CAN BUS Message, Hydraulic Oil Temperature from EPC or TCU
As AutoTrac can only function when transmission oil temperature is above 0°C, the information on transmission oil temperature is read out constantly on the CAN BUS. If, at the fourth attempt, the value can still not be recognized on the CAN BUS, this diagnostic trouble code is generated.
SSU 000237.02 (SSU 237.02)— Incorrect CAN BUS Message, Vehicle Identification Number (VIN) from BCU
This diagnostic trouble code is generated when a data transfer problem occurs between the BCU and SSU. Reception of the CAN message concerning the vehicle identification number (VIN) is intermittent or nonexistent (intermittent reception could be due to a loose wire).
SSU 000517.09 (SSU 517.09)— Incorrect CAN BUS Message, Travel Speed from StarFire ITC Receiver
This diagnostic trouble code is generated if the travel speed placed on the ISOBUS by the StarFire ITC receiver cannot be read.
SSU 000524.09 (SSU 524.09)— Incorrect CAN BUS Message, Gear Selection from EPC
This diagnostic trouble code is generated if the information on gear selection (from the EPC) is not recognized on the CAN BUS.
SSU 000628.02 (SSU 628.02)— Control Unit Internal Fault
If a fault occurs when the internal module (EEPROM) intervenes, this diagnostic trouble code is triggered.
SSU 000628.12 (SSU 628.12)— SSU Programming
Code caused by: Steering System Control Unit (SSU) detects that it is in the process of updating software.
Control Unit Response: No function available until programming is complete. Programming codes occur only during process of updating or loading new software. It is not an error and no diagnosis is required.
SSU 000629.12 (SSU 629.12)— Control Unit Internal Fault
This diagnostic trouble code is triggered if the SSU control unit detects that too much time has elapsed (watchdog).
SSU 000630.13 (SSU 630.13)— Control Unit Not Calibrated
This diagnostic trouble code is saved if the previous calibration was not saved or the new SSU control unit has not been calibrated yet.
SSU 000639.12 (SSU 639.12)— Vehicle CAN BUS, High Error Rate
The diagnostic trouble code is generated when the control unit receives too many incorrect CAN BUS messages or when it detects a general problem in the connection to the vehicle CAN BUS.
SSU 000639.13 (SSU 639.13)— Vehicle CAN BUS, Very High Error Rate
The diagnostic trouble code is generated when the control unit receives too many incorrect CAN BUS messages or when it detects a general problem in the connection to the vehicle CAN BUS.
SSU 000639.14 (SSU 639.14)— Vehicle CAN BUS, Incorrect Message
The diagnostic trouble code is generated when the control unit receives too many incorrect CAN BUS messages or when it detects a general problem in the connection to the vehicle CAN BUS.
SSU 001079.03 (SSU 1079.03)— B139 Steering Angle Sensor, Voltage Too High
This diagnostic trouble code is triggered if the power supply for wheel angle sensor (WAS) is over 5.25 volts for longer than 320 ms.
SSU 001079.04 (SSU 1079.04)— B139 Steering Angle Sensor, Voltage Too Low
This diagnostic trouble code is triggered if the power supply for wheel angle sensor (WAS) is less than 4.75 volts for longer than 320 ms. This indicates that the circuit is open.
SSU 001504.07 (SSU 1504.07)— S40 Operator Presence Switch, Signal Invalid
This diagnostic trouble code is triggered if the seat switch reports “operator on seat” for longer than 25.5 hours without interruption.
SSU 001504.09 (SSU 1504.09)— S40 Operator Presence Switch, Signal Not Received
If the information on the seat switch is not accepted on the CAN BUS after four attempts, this diagnostic trouble code is triggered. This indicates a problem in the vehicle CAN BUS.
SSU 001504.14 (SSU 1504.14)— S40 Operator Presence Switch, Noone on Operator’s Seat While AutoSteer is Running
If the AutoSteer function is activated and there is no operator on the seat for longer than 7 seconds, this diagnostic trouble code is triggered.
SSU 001504.31 (SSU 1504.31)— S40 Operator Presence Switch, Noone on Operator’s Seat While AutoSteer is Running
If the AutoSteer function is activated and there is no operator on the seat for longer than 2 seconds, this diagnostic trouble code is triggered. If no operator can be recognized on the seat for longer than 7 seconds, the AutoSteer function is switched off.
SSU 001807.02 (SSU 1807.02)— B138 Steering Wheel Position Sensor, Calibration Error
This diagnostic trouble code is triggered if false signals are sent to the SSU control unit while steering input devices SID 1 or SID 2 are being calibrated.
SSU 001807.03 (SSU 1807.03)— B138 Steering Wheel Position Sensor, Supply Voltage in Channel 1 Too High
This diagnostic trouble code is triggered if the power supply for steering wheel position sensor SID 1 is over 5.25 volts for longer than 320 ms.
SSU 001807.04 (SSU 1807.04)— B138 Steering Wheel Position Sensor, Supply Voltage in Channel 1 Too Low
This diagnostic trouble code is triggered if the power supply for steering wheel position sensor SID 1 is less than 4.75 volts for longer than 320 ms. This indicates that the circuit is open.
SSU 001807.05 (SSU 1807.05)— B138 Steering Wheel Position Sensor, Current in Channel 1 Too Low
This diagnostic trouble code is generated if less than 4 mA flow to steering wheel position sensor SID 1 for longer than 320 ms. This indicates that the circuit is open.
SSU 001807.06 (SSU 1807.06)— B138 Steering Wheel Position Sensor, Current in Channel 1 Too High
This diagnostic trouble code is generated above 20 mA flow to steering wheel position sensor SID 1 for longer than 320 ms.
SSU 001807.10 (SSU 1807.10)— B138 Steering Wheel Position Sensor, Values in Channel 1 and Channel 2 Not in Correct Ratio
This diagnostic trouble code is triggered if the values read in by steering wheel position sensors SID 1 and SID 2 differ by more than 20. This indicates a problem in steering wheel position sensor SID 1.
SSU 001807.14 (SSU 1807.14)— B138 Steering Wheel Position Sensor, Fault in Channel 1
This diagnostic trouble code is triggered if the values received by the SSU control unit (signals from steering wheel position sensor SID 1) are faulty.
SSU 001865.09 (SSU 1865.09)— ELX Message Missing
Steering System Control Unit (SSU) detects that the Vehicle Load Center (VLC) ELX output 2 message is not available on the CAN Bus.
SSU 522273.00 — Y49 Steering Control Valve, Control Signal Out of Valid Range High
The steering control valve (Y49) receives a control signal from the SSU control unit, which can also request information on the position of the valve. If the control signal is out of range high (over 85 % of the system voltage), this diagnostic trouble code is triggered.
SSU 522273.01 — Y49 Steering Control Valve, Control Signal Out of Valid Range Low
The steering control valve (Y49) receives a control signal from the SSU control unit, which can also request information on the position of the valve. If the control signal is out of range low (below 15% of the system voltage), this diagnostic trouble code is triggered.
SSU 522387.07 — Expected Steering Movement of Front Wheels is Not Detected
If, despite a steering movement being commanded, the SSU control unit fails to detect a signal from the wheel angle sensor (WAS), or the signal it does receive is too low, this diagnostic trouble code is triggered.
SSU 522394.09 — Incorrect CAN BUS Message, Information from Terrain Compensation Module (TCM)
This diagnostic trouble code is generated if the information on the TCM (Terrain Compensation Module) is not recognized on the CAN BUS after four attempts. This indicates a problem in the CAN BUS or loose connectors.
• The TCM (Terrain Compensation Module) is integrated in the StarFire ITC receiver.
SSU 522451.00 — B139 Steering Angle Sensor, Voltage in Channel 2 Too High
If the voltage at signal line 986 of channel 2 of the wheel angle sensor (WAS) is over 2.25 volts for longer than 320 ms, this diagnostic trouble code is triggered.
SSU 522451.01 — B139 Steering Angle Sensor, Voltage in Channel 2 Too Low
If the voltage at the signal line of channel 2 of the wheel angle sensor (WAS) is below 0.25 volts for longer than 320 ms, this diagnostic trouble code is triggered. This indicates that the circuit is open.
SSU 522451.14 — B139 Wheel Angle Sensor, Voltages in Channel 1 and Channel 2 Not in Correct Ratio
The wheel angle sensor (WAS) consists of two separate sensors. The signal voltage of sensor 2 is 1/2 of the signal voltage of sensor 1. The diagnostic trouble code is triggered if the difference is 0.4 volts or more.
SSU 523349.09 — AutoTrac Resume Switch Message Missing
Code caused by: Steering System Control Unit (SSU) detects that the transmission resume switch message is not available on the CAN Bus.
SSU 523651.02 — Control Unit Internal Fault
This diagnostic trouble code is triggered if an internal fault occurs in the SSU control unit.
SSU 523652.02 — Control Unit Connected to Wrong Wiring Harness Connector
This diagnostic trouble code is saved if the SSU control unit detects an erroneous signal in the circuit of the control unit identification.
SSU 523698.09 — Incorrect CAN BUS Message, Information from StarFire ITC Receiver
This diagnostic trouble code is generated if the information regarding the StarFire ITC receiver on the CAN BUS is incorrect, or if there is no information there at all.
SSU 523766.02 — Invalid Entry for System Activation
This diagnostic trouble code is triggered if the system has been deactivated at address SSU039.
SSU 523767.02 — S123/2 or S142 AutoTrac Resume Switch, Fault in the Engagement Signal
The switch that activates AutoTrac consists of a changeover contact, which allows the engagement signal to be checked. On tractors with CommandArm, switch S123/2 is installed, on tractors without CommandArm, switch S142 is installed. If a faulty engagement signal is detected, this diagnostic trouble code is triggered.
SSU 523767.14 — S123/2 or S142 AutoTrac Resume Switch, Engagement Signal Activated Too Long
This diagnostic trouble code is activated if the AutoTrac resume switch is actuated for more than 15 seconds. On tractors with ComandArm, switch S123/2 is installed, on tractors without ComandArm, switch S142 is installed. This diagnostic trouble code indicates a fault in the switch.
SSU 523768.02 — Axle Detection Invalid
Steering System Control Unit (SSU) detects that the front axle type is missing or invalid.
SSU 523768.09 — Axle Message Missing
Steering System Control Unit (SSU) detects that the front axle type message is not available on the CAN Bus.
SSU 523789.02 — No Wheel Angle Sensor Detected
Steering System Control Unit (SSU) detects that the wheel angle sensor (flow meter or axle) is not responding upon powering up.
SSU 523795.02 — Y49 Steering Control Valve, Fault during Calibration
If a left/right discrepancy is detected (signals not reflecting actual steering direction) during calibration, or if the signal from the wheel angle sensor is too low at right or left fulllock, this diagnostic trouble code is triggered. This diagnostic trouble code indicates that the hydraulic lines have been mixed up at the steering cylinder.
SSU 523795.11 — Electro-Hydraulic Steering Valve Deadband Inconsistent
Steering System Control Unit (SSU) detects that the electro-hydraulic steering valve left and right deadband values are different during calibration (greater than 4 counts difference between each check).
SSU 523795.12 — Y49 Steering Control Valve, Error Identification
The steering control valve (Y49) can send error information to the SSU control unit. This diagnostic trouble code can be triggered for a number of different reasons.
• Short in 5volt power supply to steering control valve (Y49).
• Open circuit.
SSU 523795.13 — Y49 Steering Control Valve, Calibration Error
If excessive freetravel is detected during calibration (play at the steering cylinder and/or valve), this diagnostic trouble code is triggered.
SSU 523810.00 — Control Unit, Current Too High
This diagnostic trouble code is triggered if the control unit measures too high an amperage at the connecting leads 4043/4061 for steering valve Y49. This indicates a short to ground in the circuit.
SSU 523810.01 — Control Unit, Current Too Low
This diagnostic trouble code is triggered if the control unit measures too low an amperage at the connecting leads 4043/4061 for steering valve Y49. This indicates that the circuit is open.
SSU 523821.02 — Vehicle Mismatch
Steering System Control Unit (SSU) detects that the vehicle model number or loopback wire does not match AutoTrac configuration.
SSU 523822.02 — SSU Calibration Fault / Wheel Angle Sensor-Flow Meter Direction Incorrect
Steering System Control Unit (SSU) detects that the wheel angle sensor-flow meter direction is incorrect after the manual steering portion of the SSU calibration procedure.
SSU 523822.05 — Wheel Angle Sensor-Flow Meter Current Low
Steering System Control Unit (SSU) detects that the wheel angle sensor-flow meter return current is open.
SSU 523822.06 — Wheel Angle Sensor-Flow Meter Current High
Steering System Control Unit (SSU) detects that the wheel angle sensor-flow meter return current is too high.
SSU 523822.07 — SSU Calibration Fault / Wheel Angle Sensor-Flow Meter Range Low
Steering System Control Unit (SSU) detects that the wheel angle sensor-flow meter value count is too low during the SSU calibration procedure.
SSU 523822.08 — Wheel Angle Sensor-Flow Meter Signal Fault
Steering System Control Unit (SSU) detects that the wheel angle sensor-flow meter signal is bad or there is a dead channel.
SSU 523822.10 — Wheel Angle Sensor-Flow Meter Fault / Steered Motion Detected Without Steering Wheel Motion
Steering System Control Unit (SSU) detects steering movement from the wheel angle sensor-flow meter with little or no steering wheel movement from the steering wheel position sensor 1 or 2 (SID).
SSU 523822.12 — Wheel Angle Sensor-Flow Meter Excessive Hysteresis
Steering System Control Unit (SSU) detects wheel angle sensor-flow meter is not detecting actual steering motion in the allotted time during calibration.
Attention: This fault tends to occur as additional hours accrue and the steering mechanics loosen.
SSU 523822.14 — Wheel Angle Sensor-Flow Meter Fault / Steering Wheel Motion Detected Without Steered Motion
Steering System Control Unit (SSU) detects that the steering wheel position sensor 1 or 2 (SID) shows movement (at least 90° rotation) with little or no movement from the wheel angle sensor-flow meter.
SSU 523824.03 — B138 Steering Wheel Position Sensor, Supply Voltage in Channel 2 Too High
This diagnostic trouble code is triggered if the power supply for steering input device SID 2 is over 5.25 volts for longer than 320 ms.
SSU 523824.04 — B138 Steering Wheel Position Sensor, Supply Voltage in Channel 2 Too Low
This diagnostic trouble code is triggered if the power supply (for SID 2) is less than 4.75 volts for longer than 320 ms. This indicates that the circuit is open.
SSU 523824.05 — B138 Steering Wheel Position Sensor, Current in Channel 2 Too Low
This diagnostic trouble code is generated if less than 4 mA flow to steering input device SID 2 for longer than 320 ms.
SSU 523824.06 — B138 Steering Wheel Position Sensor, Current in Channel 2 Too High
This diagnostic trouble code is generated if more than 20 mA flow to steering input device SID 2 for longer than 320 ms.
SSU 523824.10 — B138 Steering Wheel Position Sensor, Voltage in Channel 1 and Channel 2 Not in Correct Ratio
This diagnostic trouble code is triggered if the values read in by steering wheel position sensors SID 1 and SID 2 differ by more than 20. This indicates a problem in steering input device SID2.
SSU 523824.14 — B138 Steering Wheel Position Sensor, Fault in Channel 2
This diagnostic trouble code is triggered if the values received by the SSU control unit (signals from steering wheel position sensor SID 2) are faulty.
SSU 523826.00 — B139 Steering Angle Sensor, Voltage in Channel 1 Too High
If the voltage at the signal line of channel 1 of the wheel angle sensor (WAS) is over 4.5 volts for longer than 320 ms, this diagnostic trouble code is triggered.
SSU 523826.01 — B139 Steering Angle Sensor, Voltage in Channel 1 Too Low
If the voltage at the signal lines of channel 1 of the wheel angle sensor (WAS) is below 0.5 volts for longer than 320 ms, this diagnostic trouble code is triggered. This indicates that the circuit is open.
SSU 523826.02 — B139 Steering Angle Sensor, Fault during Calibration
This diagnostic trouble code is triggered if the wheel angle sensor (WAS) sends false signals to the SSU control unit during calibration.
SSU 523826.07 — B139 Steering Angle Sensor, Control Unit Recognizes No Signals
If, during calibration, despite a steering movement being made, the SSU control unit fails to detect a signal from the wheel angle sensor (WAS), or the signal it does receive is too low, this diagnostic trouble code is triggered. From the right steering stop to the left steering stop, the signal from the wheel angle sensor (WAS) must be above 1.5 volts.
SSU 523826.10 — B139 Steering Angle Sensor, Signals from Steering Wheel Position Sensor (B138) Not Recognized
If a movement is detected by the wheel angle sensor (WAS) but not by the steering input device (SID), this diagnostic trouble code is triggered.
SSU 523826.12 — Excessive Hysteresis in AutoTrac Steering
Steering System Control Unit (SSU) detects wheel angle sensor-axle is not detecting actual steering motion in the allotted time during calibration.
Attention: This fault tends to occur as additional hours accrue and the steering mechanics loosen.
SSU 523826.13 — B139 Steering Angle Sensor Not Calibrated
This diagnostic trouble code is triggered if the wheel angle sensor (WAS) is found to have an invalid calibration, or is not yet calibrated.
SSU 523826.14 — B139 Steering Angle Sensor Recognizes No Movement
The diagnostic trouble code is generated when the wheel angle sensor (WAS) does not detect any steering movement even though the steering wheel position sensor (B138) transmits steering signals (movement of steering wheel) to the SSU.
SSU 524194.09 — Incorrect CAN BUS Message, Position of Reverse Drive Lever from EPC or UIC
This diagnostic trouble code is generated if the information on reverse drive lever position (from the EPC or UIC) is not recognized on the CAN BUS.
SSU 524221.09 — Incorrect CAN BUS Message, Fault in StarFire ITC Receiver
This diagnostic trouble code is generated if the yaw rate information is not identified on the CAN BUS within 200 ms. This information is issued by the StarFire ITC receiver.
SSU 600006.31 — Diagnostic Trouble Code Not Known
This diagnostic trouble code is triggered by the CommandCenter (DTI) when the DTI receives an SSU diagnostic trouble code via the CAN BUS that is not stored in the DTI memory. This “general” diagnostic trouble code enables the CommandCenter (DTI) to display information relating to this unknown SSU diagnostic trouble code.