Case IH 17 – Transmission ECM: RANGE (G1) GEAR SHIFT SWITCH SIGNAL VOLTAGE SHORT TO GROUND OR OPEN CIRCUIT

The Transmission ECM logs this code when the voltage at ECM connector 2, pin 28 drops below 0.7 volts while the tractor is being driven or in neutral. Symptoms include clutch packs at maximum pressure with no movement, flashing Transmission Status Lamp, disabled transmission, and inability to detect the neutral position of the Range (G1) Gear Shift.

• JXC
• Magnum MX210
• Magnum MX230
• Magnum MX255
• Magnum MX285
• TN Series

1. 1

   Probe ECM connector 2, pin 28 to verify if the voltage is dropping below 0.7 volts (indicating an open circuit or short to ground)

2. 2

   Check for a faulty circuit shorted to 12 volts between ECM connector 2, pin 20 and the Range (G1) Gear Shift Switch

3. 3

   Look for a short to 5 volts between the switch terminals, or a 5V/12V short between the switch and ECM connector 2, pin 28

4. 4

   Inspect the common 5-volt sensor supply wire coming from the ECM

5. 5

   Check test H9, Channel 17 to see if the value is abnormally high (above 860 counts)

6. 6

   Check test H5 to see if it fails to display the transition between d0 and d34

1. 1

   Access the ECM and Switch

   Locate the Transmission ECM and the Range (G1) Gear Shift Switch on the transmission housing/linkage.

2. 2

   Inspect and Repair Wiring

   Repair any damaged, chafed, or broken wires between ECM connector 2 and the gear shift switch. Pay special attention to pins 20 and 28.

3. 3

   Test the Switch

   If the wiring harness is fully intact and provides the correct 5V reference and continuity, the fault lies within the switch itself.

4. 4

   Replace the Switch

   Remove the faulty Range (G1) Gear Shift Switch and install a new OEM replacement.

5. 5

   ECM Verification

   If both the wiring and the switch test perfectly fine, replace the Transmission ECM as the last possible cause.

6. 6

   Clear Codes and Test

   Clear the fault codes and test drive the tractor to ensure the Transmission Status Lamp stops flashing and normal gear engagement is restored.