Case IH 46 – Transmission ECM: FUSE ERROR

The module detects that the keyed 12-volt supply at ECM connector 2, pin 1 is low, while the voltage at connector 2, pin 10 is high. The transmission is severely limited, neutralizing forward movement, and only the Synchronizer Shuttle (Reverse) Solenoid remains available.

• MX Maxxum
• Case IH JX series
• Maxxum
• TN75A

1. 1

   Check the transmission ECM fuses. Code 46 specifically points to a blown 5-amp fuse (usually Fuse 15) that protects the ECM connector 2, pin 1 circuit.

2. 2

   With the tractor turned on, test for keyed 12 volts at ECM connector 2, pin 1.

3. 3

   Check for faulty wiring or an open circuit between the battery and the key switch, or between the key switch and the fuse panel.

4. 4

   If diagnosing a true Reverse Solenoid short (Code 66): Check for a short to ground or open circuit between ECM connector 1, pin 17 and the Synchronizer Shuttle (Reverse) Solenoid Coil terminal. Test the resistance across the solenoid coil terminals to ensure it is not shorted out (reading 0 ohms).

1. 1

   Power Down

   Turn off the tractor, engage the parking brake, and ensure the Power Shuttle FNR Lever is in neutral.

2. 2

   Locate and Replace the Fuse

   Access the main fuse panel and locate the 5-amp transmission ECM fuse (Fuse 15). If blown, replace it with a new 5-amp fuse.

3. 3

   Trace Shorts

   If the new fuse blows immediately upon turning the key switch, trace the wiring harness from the key switch to the ECM (connector 2, pin 1) to locate and repair the short to ground.

4. 4

   Inspect the Solenoid

   Locate the Power Shuttle Control Valve on the bottom of the transmission. The Synchronizer Shuttle (Reverse) Solenoid is the coil positioned toward the rear of the tractor (the forward solenoid is toward the front).

5. 5

   Replace Solenoid Coil

   Disconnect the wiring harness from the reverse solenoid. Remove the retaining fastener and slide the faulty coil off the valve stem. Install the new coil and reconnect the harness.

6. 6

   Clear Codes

   The transmission can be re-enabled and codes cleared by cycling the Power Shuttle FNR (Forward/Neutral/Reverse) Lever or the Clutch Pedal.