New Holland 103-02 – ECU: Terminal 15 Failure - Data Erratic, Intermittent or Incorrect

Terminal 15 is the switched power supply circuit that is activated when the ignition key is in the ON or RUN position. Fault code 103-02 is triggered when the Engine Control Unit (ECU) detects that the voltage or data on this circuit is unstable, intermittent, or incorrect. This disruption can cause the machine to fail to start, shut down intermittently, or experience various electrical system malfunctions.

• Boomer Series
• T Series
• TC Series
• TD Series
• TL Series
• TD60D
• TD70D
• TD75D
• TD80D
• TD90D
• TD95D
• TD5050
• TL80A
• TL90A
• TL100A
• TT55
• TT65
• TT75
• Loaders
• Skid Steers
• Forage Harvesters

1. 1

   Record any other active fault codes and observe machine behavior to identify when the fault occurs

2. 2

   Check battery voltage with the machine off (should be approximately 12.6V)

3. 3

   Test alternator output at the battery terminals with the engine running (should be 13.5V to 14.5V)

4. 4

   Inspect the main fuse panel for blown fuses or faulty relays related to the ignition circuit or ECU

5. 5

   Visually inspect the wiring harness between the ignition switch and the ECU for chafing, corrosion, or loose connections

1. 1

   Disconnect battery

   Disconnect the negative battery terminal before performing any electrical repairs to prevent short circuits.

2. 2

   Test ignition switch

   Access the back of the ignition switch. With the key in the ON position, use a multimeter to test for stable voltage at Terminal 15 (or IGN). Wiggle the key and harness to check for voltage drops indicating a faulty switch.

3. 3

   Check wiring continuity

   Using a multimeter, check for continuity on the wire from the ignition switch Terminal 15 output to the corresponding ECU input pin. Repair or replace the wire if an open circuit is found.

4. 4

   Inspect for shorts to ground

   Test for continuity between the Terminal 15 wire and the machine's chassis. There should be no continuity.

5. 5

   Check ECU power and ground

   Verify the ECU is receiving a stable power supply and has a solid, corrosion-free ground connection.

6. 6

   Replace faulty components

   Replace the ignition switch if it failed the voltage test, or repair/replace damaged wiring using OEM-grade connectors and terminals.