Case IH 3156 (F-729-05) – Engine Control Unit (ECU) A-095: Intake air heater actuator has an open load error

The Engine Control Unit (ECU) monitors the intake air heater relay (designated as relay K-023) control circuit for an open load condition. If an open circuit or no-load condition is detected in the wiring or the relay itself, this fault code is triggered.

• VESTRUM CVX
• 240 Series Combines (7240, 8240, 9240)
• 5140 Combine
• 5150 Combine
• 6088 Combine
• 7088 Combine
• Magnum Series Tractors (180, 200, 220, 235-340, MX210, MX230, MX255, MX285)
• Puma Series Tractors (125, 150, 185, 210)
• Steiger/Quadtrac Series Tractors
• Farmall Series Tractors (40-45-50)
• Patriot Series Sprayers (2250, 3230, 3240)
• Case 580 Super N Backhoes

1. 1

   Check that the tractor battery power supply has not been connected to an external power supply (like a jump starter). If connected, disconnect it and test for normal operation.

2. 2

   Visually inspect the relevant harnesses and connectors for the K-023 Grid Heater Relay for damage, bent or dislocated pins, corroded terminals, or broken wires.

3. 3

   Verify that the connectors are fully seated and perform a harness flex test to reveal any intermittent breaks or shorts in the wiring between the ECU A-095 and the K-023 relay.

4. 4

   Test the wiring circuit for continuity to ground and to the ECU to identify a broken/disconnected wire or a defective relay.

5. 5

   If wiring and relay test fine, check the ECU A-095 for the appropriate software version and re-flash if necessary.

1. 1

   Turn off the machine and disconnect the negative battery cable to prevent electrical shorts.

2. 2

   Locate the intake air heater relay (Grid Heater Relay K-023).

   Its location varies by model but is typically found on the engine frame bracket or near the main engine fuse/relay block.

3. 3

   Disconnect the grid heater relay electrical connector (Connector X-215 or X-330A/B).

4. 4

   Detach the grid heater relay from its mounting bracket.

5. 5

   If the wiring harness connector is damaged or corroded, splice in a new replacement connector.

6. 6

   Install the new grid heater relay and secure it to the bracket.

7. 7

   Reconnect the electrical connector, ensuring the locking tab clicks into place.

8. 8

   Reconnect the battery, turn the key to the ON position, and clear the fault codes using your diagnostic tool.

9. 9

   Cycle the key and verify that the code does not return during the cold-start grid heater cycle.