Case IH 3414 – Engine Control Unit (ECU) / Glow Plug Control Unit (GCU): Short circuit in cylinder 1 glow plug

The engine control system has detected that the electrical circuit for the glow plug (heater plug) on cylinder #1 is shorted, which can prevent proper pre-heating of the cylinder and lead to hard starting or excessive smoke during cold starts.

• Farmall
• skid steer
• SR250
• TR270
• Farmall 65A
• Farmall 75A
• Farmall 85A
• Farmall 95A
• Farmall 105A
• Farmall 115A
• JX series
• Quantum series
• W-Series loaders

1. 1

   Visually inspect the relevant harnesses and connectors for damage, bent, or dislocated pins at the cylinder 1 glow plug and the GCU

2. 2

   Verify that the wiring and connectors are free of damage, specifically checking the wire running from the GCU to the Cylinder 1 glow plug for a short to ground or a short to battery

3. 3

   Disconnect the cylinder 1 glow plug and test its resistance with a multimeter (a reading of 0 ohms or continuity to the engine block indicates an internal short in the glow plug)

4. 4

   If the wiring is intact and the glow plug tests good, check the ECU power stages (the ECU may need to be re-initialized using the EST or replaced)

1. 1

   Power Down

   Turn the key to the OFF position and disconnect the negative battery cable to prevent electrical arcing.

2. 2

   Locate Cylinder 1

   Locate the glow plug for cylinder 1 on the engine cylinder head.

3. 3

   Disconnect

   Carefully remove the electrical connector/wire nut from the top of the cylinder 1 glow plug.

4. 4

   Inspect & Repair Wiring

   Inspect the wire for melted insulation or chafing against the engine block. Repair any damaged wiring sections.

5. 5

   Remove Faulty Plug

   If the wiring is good, use a deep socket to carefully unthread the shorted glow plug from the cylinder head.

6. 6

   Install New Plug

   Thread the new OEM glow plug into the cylinder head by hand to prevent cross-threading, then torque to the manufacturer's specification.

7. 7

   Reconnect

   Reattach the electrical connector to the glow plug.

8. 8

   Clear Codes

   Reconnect the battery. Turn the Key ON (Engine OFF) and use the EST service tool to clear fault code 3414. Cycle the key and verify the code does not return.