John Deere 1518 – Header Control Unit (HCU) / E01: Header Not Connected or Invalid Connection

The Header Control Unit (HCU) has detected that the header is either not connected or the connection is invalid. This fault is triggered when the system cannot properly identify the type of header attached to the combine, which relies on a specific set of electrical circuits (436, 487, 488, and 489) known as the header select lines or front end select circuits.

• CTS
• 90-series corn heads
• 9000 series
• 9450
• 9550
• 9560
• 9650
• 9660
• 9750
• 9760
• 9860 STS

1. 1

   Visually inspect the main 31-pin electrical connector (X901) between the combine's feeder house and the header for corrosion, dirt, moisture, or damaged/pushed-out pins

2. 2

   Check the wiring harness along the feeder house for visible damage, cuts, abrasions, or rodent damage

3. 3

   Verify 12V power supply at Pin 4 (Circuit 021/016) on the combine-side connector using a multimeter

4. 4

   Check continuity and integrity of the header identification circuits at the 31-pin connector: Pin 16 (Circuit 436, Front End Select 8), Pin 17 (Circuit 488, Front End Select 2), Pin 18 (Circuit 489, Front End Select 1), and Pin 28 (Circuit 457, Front End Select)

5. 5

   Ensure a solid ground connection at Pin 12 (Circuit 10) on the 31-pin connector

6. 6

   Attempt to recalibrate the header through the combine's display to rule out a lost or incorrect calibration

1. 1

   Disconnect and clean connector

   Disconnect the large 31-pin electrical connector between the combine and the header. Clean both the male and female ends using an appropriate electrical contact cleaner to remove any dirt, debris, or corrosion.

2. 2

   Inspect and repair connector pins

   Carefully inspect each of the 31 pins on both sides of the connector. Straighten or replace any damaged or bent pins. If the entire connector housing is damaged, replace it.

3. 3

   Test header select jumper

   Check the header's internal jumper connections to the 12V source. If using a non-John Deere header, install a jumper wire in the header's harness to allow the combine to recognize it. For OEM headers, repair any faults found in this internal jumpering.

4. 4

   Test wiring harness continuity

   Test the continuity of the header select circuits (436, 487, 488, 489) and the main power and ground circuits between the Header Control Unit and the 31-pin connector. Consult the machine's electrical schematic and repair any open or shorted wires.

5. 5

   Check and replace HCU

   Ensure the Header Control Unit (HCU) connectors are secure and free of corrosion. If all wiring and connectors are confirmed to be in good condition and the fault persists, replace the HCU.