Case IH 3169 – Engine Control Unit (ECU A-095): Fuel filter heater ECU driver has an over temperature error

The ECU monitors the signal circuit of the fuel filter heater relay (K-024). If the ECU detects an over-temperature condition, an excessive current draw, or a short-to-battery in this circuit for a period greater than 200 milliseconds, it will log this fault to protect the ECU's internal driver from burning out.

• Steiger T4B
• Case IH 240 Series Axial-Flow Combines (e.g., 7240, 8240, 9240)
• Case IH Magnum Series (235 - 340, Series 4)
• Case IH Puma Series (e.g., 140, 165, 180, 195, 210, 225 CVX)
• Case IH A8800 Series Sugar Cane Harvesters

1. 1

   Verify Active Status: Use the Electronic Service Tool (EST) to check if the fault is currently active or stored as an intermittent historical code.

2. 2

   Relay Circuit Test: Locate the fuel filter heater relay (K-024). Test the relay coil for an internal short circuit that could be drawing excessive amperage.

3. 3

   Wiring Harness Inspection: Inspect the wiring harness between ECU A-095 and relay K-024. Look for chafed wires causing a short-to-battery or short-to-ground.

4. 4

   Heater Element Test: Check the fuel filter heater element itself. A failing heater element can pull too much current, causing the relay and subsequently the ECU driver circuit to overheat.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to prevent further damage to the Engine ECU.

2. 2

   Inspect and Replace Relay K-024

   Locate the power distribution box or relay panel. Remove the fuel filter heater relay (K-024). Test the resistance across the coil pins. If the coil is burnt out, reads out of specification, or shows a dead short, replace the relay.

3. 3

   Check the Harness

   Using a multimeter, check the continuity of the signal wire from the relay block back to the Engine ECU (A-095) harness connector. Repair any damaged wiring.

4. 4

   Inspect the Fuel Filter Heater

   Examine the fuel filter housing and the heater element plug. If the connector is melted or the heater element is shorted internally, replace the fuel filter heater assembly.

5. 5

   Clear Codes and Test

   Reconnect the battery. Use the EST to clear the fault codes. Turn the key to the ON position (which primes the fuel system and activates the heater) and monitor the EST to see if code 3169 returns.

6. 6

   ECU Replacement (Worst Case)

   If the wiring, relay, and heater element are all in perfect working order but the code immediately returns as active, the internal driver inside ECU A-095 has likely failed permanently due to the over-temperature event. The ECU will need to be replaced and reprogrammed by a dealer.