New Holland ENG 3342 – Engine Control Unit (ECU): Power Stage Air Heater 2 Actuator - No Signal

The engine control system has detected an open load or a complete loss of signal in the control circuit for the intake air heater (grid heater) relay. The controller is trying to monitor or command the second stage of the grid heater to warm the intake air for cold starting, but it cannot detect the actuator/relay in the circuit.

• T7.165S
• T7.175
• T7.190
• T7.210
• T7.225
• T8.380
• CR9090
• CX8080 Elevation
• CX8090 Elevation

1. 1

   Check battery voltage and perform a load test, as low voltage can cause the ECU to drop communication with high-draw relays

2. 2

   Inspect the high-current grid heater fuse (typically a 200A Mega fuse) to see if it has blown

3. 3

   Inspect the grid heater relay wiring harness for chafing, breaks, or disconnected plugs

4. 4

   Test the Grid Heater Power Relay for internal open faults and verify it receives the command signal from the ECU when the key is ON in cold temperatures

1. 1

   Disconnect Power

   Always disconnect the negative battery terminal before working on the high-current grid heater circuit.

2. 2

   Inspect and Replace Fuses

   Locate the grid heater fuse block. If the 200A fuse is blown, replace it. (Note: A blown fuse usually indicates a short, so inspect the heater element before powering back up).

3. 3

   Harness Replacement

   If the diagnostic checks reveal a broken wire in the relay harness (a known issue on T7 models), disconnect the harness from the ECU and the relay, and install a replacement Grid Heater Relay Wiring Harness.

4. 4

   Relay Replacement

   If the wiring is intact but the relay has an open internal coil (failing the continuity test), unbolt the heavy-gauge battery and heater cables from the Grid Heater Power Relay. Unplug the signal connector, unbolt the relay from the chassis, and install the new relay.

5. 5

   Reassembly and Clearing Codes

   Reconnect all heavy-gauge cables and the signal harness. Reconnect the battery.

6. 6

   Verification

   Connect a diagnostic tool to clear the ENG 3342 code. Cycle the ignition key to the ON position and verify that the grid heater indicator light illuminates on the dash and the code does not return.