Case IH 62 – Transmission ECM: HI_LO_SYNCRO_SW_LO_DIS_ERR (17 CP/SL Dis)

Voltage from Synchronizer Hi-Lo (Forward) Position Switch (S) Short to Ground or Open Circuit. When this fault is triggered, the Transmission Status Lamp will flash in an alternating manner and the transmission will be disabled as a safety precaution.

• JXC
• Farmall series
• JX series
• CX series
• TN Series (TN55, TN65, TN70, TN75)
• TNA Series
• TL series

1. 1

   Locate the Synchronizer Hi-Lo (Forward) Position Switch on the left side of the transmission, between the Power Shuttle Control Valve and the Service Control Valve (forward-most switch).

2. 2

   Check ECM Voltage: While the Power Shuttle FNR Lever is in the Reverse or Neutral position, check if the voltage at ECM connector 2, pin 23 is above 4.2 volts.

3. 3

   Inspect Wiring: Check for a short to ground, an open circuit, or a short to 12 volts between ECM connector 2, pin 20 and the Synchronizer Hi-Lo (Forward) Position Switch.

4. 4

   Check the 5-Volt Reference: Verify that the common 5-volt sensor supply wire from ECM connector 2, pin 20 is not shorted to ground or open between the switch and any other 5-volt sensor.

5. 5

   Test the Switch: Test the switch itself for internal shorts or open continuity.

6. 6

   Check EST/CDU Data: If using an Electronic Service Tool (EST) or CDU, check if H9, channel 5 is above 860 counts, or if HD displays 'unkn'.

1. 1

   Preparation

   Park the tractor on a level surface, engage the parking brake, and turn off the engine. Disconnect the negative battery cable to protect the Transmission ECM.

2. 2

   Access the Switch

   Locate the Synchronizer Hi-Lo (Forward) Position Switch on the left side of the transmission housing (forward-most switch of the two located near the Power Shuttle Control Valve).

3. 3

   Disconnect and Inspect

   Unplug the electrical harness connector from the switch. Inspect the pins for corrosion, pushed-back terminals, or water ingress. Clean with contact cleaner if necessary.

4. 4

   Repair Wiring (If Applicable)

   If the diagnostic tests revealed a short or open circuit in the harness between the switch and ECM connector 2, repair the damaged wire or replace the harness section.

5. 5

   Replace the Switch (If Faulty)

   If the wiring is intact but the switch failed the continuity test, unscrew the faulty switch from the transmission housing. Install the new switch (apply appropriate thread sealant if specified by the OEM) and tighten to spec.

6. 6

   Reassembly

   Reconnect the electrical harness to the switch and reconnect the battery.

7. 7

   Clear Codes

   The cause must be resolved and the error must be cleared from the Transmission ECM using the CDU (Control Display Unit) or EST (Electronic Service Tool) via the HF Menu.