Case IH 9023 – Engine Control Unit (ECU) / Electro-Hydraulic Controller / Navigation/Steering Controller (NAV Controller) / Hydraulic Drive Unit (HDU): 5V DC Supply 3 defect (High or Low) / Defect power supply at OPV and MUX

The auto-guidance system attempted to learn the electrical offset required to actuate the right-turn proportional steering valve, but the returned electrical value fell outside the acceptable programmed window. This is often caused by a failing 5V reference circuit, a faulty steering angle sensor, or erratic hydraulic pressure.

• STX Steiger
• Steiger
• Magnum
• Puma
• Patriot

1. 1

   Check the 5V Reference Circuit: Since code 9023 indicates a 5V DC Supply 3 defect, use a multimeter to verify the 5V reference voltage at the steering controller and steering angle sensor.

2. 2

   Check Sensor Voltage Range: Access the diagnostic screen on your AFS Pro display. Observe the steering sensor voltage range (Left – Center – Right). The normal voltage range should be exactly +/- 1.25 to 1.75 volts from the center value.

3. 3

   Check for Erratic Readings: Slowly turn the steering wheel and watch the voltage readings. If they jump erratically, check for air in the hydraulic steering lines.

4. 4

   Inspect Linkages: Ensure the steering angle sensor linkage is not bent, binding, or loose.

1. 1

   Clear the Fault

   On the AFS display, navigate to INFO > FAULTS, record the code, and select CLEAR FAULT.

2. 2

   Bleed the Hydraulics

   Bleed the hydraulic steering cylinder to remove any trapped air that could cause erratic valve response during calibration.

3. 3

   Adjust Sensor Linkage

   If the diagnostic voltage values are out of range, manually adjust the steering angle sensor linkage (located on the wheel end/axle) until the center voltage is within spec.

4. 4

   Recalibrate

   Park the machine on a flat, level surface with the wheels pointing straight forward. Initiate the automated Steering Valve Calibration via the AFS Pro / Viper display.

5. 5

   Address the 5V Short

   If the calibration fails immediately and Code 9023 returns, disconnect sensors on the 'Supply 3' 5V circuit one by one until the voltage returns to normal, identifying the shorted component.