Case IH F-3509-1 - CGR – CGR: CGR: Receiver Supply Voltage

A critical undervoltage condition on the supply circuit powering the GPS/Guidance receiver, causing the guidance system, RTK, and auto-steer functions to drop offline or behave erratically.

• MAGNUM AFS Connect
• STEIGER AFS Connect
• Case IH AFS Connect Magnum Tractors (Models 180, 200, 220, 240, 250, 280, 310, 340, 380)

1. 1

   Verify the tractor's main battery voltage and alternator output (system voltage dropping below 11.5V can trigger this code).

2. 2

   Inspect the CGR serial interface cable running from the cab roof to the receiver for chafing, pinched wires, or weather damage.

3. 3

   Disconnect the CGR harness at the receiver and check for moisture intrusion, corrosion, or pushed-out pins.

4. 4

   Using a multimeter, probe the supply and ground pins at the CGR connector with the key ON to verify voltage.

1. 1

   Power Down

   Turn off the machine and disconnect the battery ground cable to prevent electrical spikes during repair.

2. 2

   Address Wiring

   If the diagnostic tests revealed low voltage at the connector, trace the CGR serial interface cable back to the cab bulkhead. Repair any damaged wire sections or replace the interface cable entirely. Clean any corroded pins with electrical contact cleaner and apply dielectric grease.

3. 3

   Replace the CGR

   If the wiring harness provides the correct voltage but the receiver still logs F-3509-1, the CGR unit is internally shorted/failed. Unbolt the receiver from the roof mounting bracket and disconnect the antenna/serial cables.

4. 4

   Install New Receiver

   Mount the replacement CGR GPS Antenna Receiver and securely fasten the connections.

5. 5

   Software Flash/Update

   Reconnect the battery. A new CGR module will likely require a software flash (e.g., to CGR software version 1.1.0.0 or 2.1.0.0) via the dealer diagnostic tool to communicate properly with the AFS Pro 1200 display.

6. 6

   Clear and Test

   Clear the F-3509-1 fault code. Move the tractor outside to a clear view of the sky and verify that the GNSS receiver acquires a signal and maintains stable voltage.