Case IH 21 – Power Shuttle ECM: CH_HARN_ERR 1 Fixed [Link] / Chassis Harness Error

Indicates an open circuit between the Power Shuttle ECM Harness and the Power Shuttle Transmission Side Harness, which hinders communication. The transmission is disabled but can be temporarily re-enabled by cycling the Power Shuttle FNR Lever. Inching the tractor with the clutch pedal becomes impossible.

• JXC
• JX
• Farmall
• TN
• TNA
• TND
• TNS

1. 1

   Check the Power Shuttle ECM to PS ECM Harness connections at connectors CN1 and CN2 under the instrument panel.

2. 2

   Check the PS ECM Harness to PS Transmission Side Harness connection at CN 9 A-D or CN 9 (24 pins), located under the hood on the engine side of the firewall.

3. 3

   Check the PS Transmission Side Harness to the Dump Solenoid and F/R Synchronizer Position Sensors, located on the left side of the transmission by the Power Shuttle Control Valve.

1. 1

   Turn the starter key to the OFF position.

2. 2

   Inspect the wiring harness at the firewall (CN 9) for loose pins, corrosion, or a disconnected plug.

   Reconnect or clean as necessary.

3. 3

   Inspect the connectors at the Dump Solenoid and the F/R Synchronizer Position Sensors on the left side of the transmission.

   Ensure they are securely plugged in and the wires are not chafed or broken.

4. 4

   Inspect the CN1 and CN2 connectors at the Power Shuttle ECM under the dash.

5. 5

   Repair any broken wires or replace the damaged section of the chassis/transmission harness.

6. 6

   Clear the error using the tractor's CDU (Customer Display Unit) or the EST (Electronic Service Tool) via the HF Menu.

   Once the physical wiring issue is resolved, the error will not clear itself and must be cleared manually.