New Holland 3415 – ECU: Short Circuit in Cylinder 2 Glow Plug

The Engine Control Unit (ECU) has detected a short circuit in the electrical circuit of the glow plug for cylinder number 2. This condition indicates that electrical current is diverting from its intended path, likely to ground, before reaching the glow plug's heating element. This prevents the glow plug from heating correctly and affects the proper operation of the engine's ignition system for that specific cylinder, leading to hard starting, rough idling, and white smoke from the exhaust, especially in cold weather.

• T1510
• T1520
• T2210
• T2220
• T2310
• T2320
• T2330
• T2410
• T2420
• TC18
• TC21
• TC21D
• TC21DA
• TC25
• TC25D
• TC27D
• TC29
• TC29D
• TC29DA
• TC30
• TC31DA
• TC33
• TC33D
• TC34DA
• TC35
• TC35A
• TC35D
• TC35DA
• TC40
• TC40A
• TC40DA
• TC45
• TC45A
• TC45D
• TC45DA
• TC48DA
• TC55DA
• TZ18DA
• TZ24DA
• Boomer 20
• Boomer 24
• Boomer 25
• Boomer 30
• Boomer 35
• C175
• L125
• L140
• L150
• L160
• L170
• L175
• L255
• L465
• L565
• LS125
• LS140
• LS150
• LS160
• LS170
• LX465
• LX485
• LX565
• LX665
• 3415

1. 1

   Ensure the engine is cool and disconnect the negative battery terminal to prevent electrical shorts.

2. 2

   Visually inspect the cylinder 2 glow plug (second cylinder from the front of the engine) and its wiring harness/connector for melted insulation, chafed wires, or corrosion.

3. 3

   Perform a glow plug resistance test: Disconnect the connector and measure resistance between the glow plug terminal and engine ground. To ensure accuracy, touch the two meter leads together first, note their resistance, and subtract it from your measurement. A good plug reads 0.5 to 2.0 ohms; an infinite (OL) or significantly different reading indicates an internally shorted or open plug.

4. 4

   Perform a wiring harness continuity test: With the glow plug disconnected, inspect the harness connector for any burnt or melted areas. Test for continuity between the harness connector terminal and engine ground. If the multimeter beeps or shows continuity, there is a short to ground in the wiring harness between the ECU and the glow plug.

1. 1

   Prepare for removal

   Ensure the engine is cool and the negative battery cable is disconnected. Thoroughly clean the area around the cylinder 2 glow plug using compressed air to prevent debris from falling into the cylinder.

2. 2

   Remove faulty glow plug

   Disconnect the electrical wire/connector from the top of the glow plug. If there is a bus bar connecting all glow plugs, remove the nut holding the power wire to the bar and then the nuts securing the bar to each glow plug. Using a deep socket and wrench, carefully turn the glow plug counter-clockwise. If stuck, apply penetrating oil and let it soak to avoid breaking it.

3. 3

   Install new glow plug

   Clean the cylinder head threads with a thread chaser. Apply a small amount of anti-seize compound to the new glow plug threads. Thread it into the cylinder head by hand to avoid cross-threading, then torque to 12-15 ft-lbs (or specific model spec). Do not overtighten, as this can damage the plug or the cylinder head.

4. 4

   Repair wiring harness

   If diagnostic tests indicated a short to ground in the wiring harness rather than a faulty plug, repair or replace the damaged section of the harness.

5. 5

   Finalize and test

   Reconnect the electrical connector or bus bar to the glow plug. Reconnect the negative battery terminal. Start the engine to verify the repair and clear the fault code from the ECU using a diagnostic tool.