New Holland ENG 3698 – ENGINE controller: Failure in glow plug cylinder 4

The engine control system has detected an electrical fault (such as an open circuit, short circuit, or failure to draw the correct current) in the glow plug specifically located in cylinder number 4.

• 200 series
• 300 series
• L218
• L220
• L225
• C227
• C232
• C337
• SR175
• T4
• T5
• TL
• TN
• TD

1. 1

   Check the glow plug relays and fuses, as relays are a common failure point on New Holland skid steers.

2. 2

   Inspect the wiring harness and electrical connector going to the cylinder 4 glow plug for corrosion, chafing, or a loose connection.

3. 3

   Test for voltage by disconnecting the wire from the cylinder 4 glow plug, turning the key to the 'ON' position to trigger the pre-heat cycle, and verifying that a full 12V is reaching the connector.

4. 4

   Measure the resistance (ohms) of the cylinder 4 glow plug. If it reads infinite resistance (open circuit) or zero resistance (shorted), the glow plug has failed internally.

1. 1

   Disconnect Power

   Disconnect the negative battery cable to prevent accidental shorts while working on the electrical system.

2. 2

   Locate the Component

   Locate the cylinder 4 glow plug on the engine cylinder head (typically the cylinder closest to the flywheel/rear of the engine, but verify orientation for your specific FPT engine).

3. 3

   Remove the Connector

   Carefully remove the electrical spade connector or retaining nut securing the wire to the top of the glow plug.

4. 4

   Extract the Glow Plug

   Apply penetrating oil to the base of the glow plug if there is heavy soot or rust. Using a deep socket, carefully unscrew the glow plug from the cylinder head. Caution: Do not force it if it binds, as breaking a glow plug off in the cylinder head will require major engine disassembly.

5. 5

   Install the New Part

   Thread the new glow plug in by hand to prevent cross-threading, then tighten it to the manufacturer's specified torque.

6. 6

   Reconnect

   Reattach the electrical wire to the glow plug terminal and reconnect the battery.

7. 7

   Clear Codes

   Use a compatible diagnostic tool or CAN-bus DTC eraser to clear the ENG 3698 code from the Engine ECU. Start the engine to verify the code does not return.