John Deere 1498 – ACU: Missing Header Engage CAN Message

The system has detected a communication breakdown on the CAN bus where the message confirming the header engagement status from the Armrest Control Unit (ACU) is missing. When this message is not detected by other control modules, normal header functions may be inhibited. Variants of this code indicate specific electrical circuit faults, such as an open, short, over voltage, or over temperature condition in the header engage output transistor or the electric clutch circuit.

• 9470STS
• 9560STS
• 9570STS
• 9650STS
• 9660STS
• 9670STS
• 9750STS
• 9760STS
• 9770STS
• 9860STS
• 9870STS
• 9880STS
• S540
• S550
• S560
• S650
• S660
• S670
• S670H
• S680
• S680H
• S685
• S685H
• S690
• S690H
• S760
• S770
• S780
• S785
• S790
• T550
• T560
• T660
• T670
• W540
• W550
• W650
• W660
• 9400
• 9410
• 9450
• 9500
• 9501
• 9510
• 9540
• 9550
• 9560
• 9580
• 9600
• 9610
• 9640
• 9660
• 9660WTS
• 9670
• 9680
• 9780
• C670
• CTS
• CTS II

1. 1

   Check for other active CAN bus codes that might indicate a wider network problem, such as a faulty terminating resistor.

2. 2

   Visually inspect the wiring harness and connectors between the Armrest Control Unit and the header's electromagnetic clutch for corrosion, pinched/frayed wires, or loose connections (including checking for rodent damage to ground wires).

3. 3

   With the engine off and the header engage switch on, check voltage at the electric clutch hot terminals (should be a minimum of 11 volts).

4. 4

   Test the continuity of the electric clutch coil to identify any open circuits or damage.

5. 5

   Inspect the seat switch to ensure it is functioning correctly, as a faulty switch can prevent header engagement.

6. 6

   Check fuses and relays related to the Armrest Control Unit, the header engagement circuit, and the clutch relay.

1. 1

   Prepare machine for service

   Shut off the engine, set the parking brake, and remove the key before beginning any repairs.

2. 2

   Clean and tighten connections

   Check and tighten all electrical connections for the header clutch. Clean any corroded connectors found during the visual inspection.

3. 3

   Replace electromagnetic header clutch

   If diagnostic checks reveal low voltage or an open circuit at the electric clutch, and the wiring is intact, replace the electromagnetic header clutch.

4. 4

   Replace Armrest Control Unit (ACU)

   If the clutch and wiring are in good condition but the fault persists (especially if code C00 1498 11 is present, indicating a faulty output transistor), replace the Armrest Control Unit.

5. 5

   Clear codes and retest

   After replacing any components, clear the diagnostic trouble codes and operate the machine to ensure the fault does not return.