Case IH F-3509-0 - CGR – Engine Control Unit (ECU): Receiver Supply Voltage

Failure related to power supply 1 for the 5-volt sensor of the ECU, which may include overvoltage, short circuit, undervoltage, or excessive temperature.

• MAGNUM AFS Connect
• STEIGER AFS Connect
• Austoft 9900

1. 1

   Connect a standardized diagnostic scan tool to the machine to pull all active and stored error codes from the controller.

2. 2

   Verify the receiver/sensor supply voltage at the module pins using a multimeter. You should expect to see a steady +5 V supply voltage and a 0 V reference ground.

3. 3

   Check the wiring harness for continuity to ground to rule out a short circuit on the high-side output driver.

1. 1

   Retrieve Data

   Use a scan tool to read the exact F-3509 sub-code (e.g., -03, -04, -05) to determine if the circuit is experiencing overvoltage, undervoltage, or a short to ground.

2. 2

   Isolate the Circuit

   Disconnect the affected 5-volt receiver/sensor from the wiring harness.

3. 3

   Test the Harness

   Measure the voltage at the connector coming from the ECU. If the voltage is outside the 5V specification, inspect the entire length of the harness for chafing, pinched wires, or melted insulation that could cause a short to ground or cross-voltage.

4. 4

   Inspect Connectors

   Check the ECU and receiver connectors for bent pins, corrosion, or water intrusion. Clean or replace connector pins as necessary.

5. 5

   Test the ECU Driver

   If the wiring harness tests perfectly but the supply voltage is still incorrect (or the ECU is logging an excessive temperature failure on the output driver), the internal ECU power supply driver has failed.

6. 6

   Replace/Reprogram

   Replace the damaged wiring, the shorted receiver/sensor, or the ECU itself. Clear the fault codes with the scan tool and cycle the key to verify the repair.