Massey Ferguson E4340.03 – EEM4 (Electronic Engine Management 4): DEF Suction Supply Pipe Heater Resistance Is High

The DEF suction line contains an integrated heating element designed to thaw frozen DEF in cold climates. This code triggers when the controller detects that the resistance in this heater circuit is abnormally high, or that the control circuit is shorted to battery voltage (High Source).

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• MF 4707
• MF 4708
• MF 4709
• MF 4710
• MF 5608
• MF 5609
• MF 5610
• MF 5611
• MF 5612
• MF 5613
• MF 5710 SL
• MF 5711 SL
• MF 5712 SL
• MF 5713 SL
• MF 7614
• MF 7615
• MF 7616
• MF 7618
• MF 7619
• MF 7620
• MF 7622
• MF 7624
• MF 7626
• MF 7714
• MF 7715
• MF 7716
• MF 7718
• MF 7719
• MF 7720
• MF 7722
• MF 7724
• MF 7726

1. 1

   Turn the ignition OFF for at least 60 seconds to allow the EEM4 ECU to power down completely and save data.

2. 2

   Locate and inspect the DEF suction line heater electrical connector (X579) for corrosion, moisture, or pushed-out terminals.

3. 3

   Measure the resistance across the heater element pins on the line side using a multimeter (an 'OL' reading indicates a burned-out heating element).

4. 4

   Check the engine harness side of the connector for a short to battery voltage (High Source) on the control circuit.

5. 5

   Test the DEF line heater relay to ensure it is not stuck closed, which would send constant power to the line and cause it to overheat.

1. 1

   Ensure the machine is turned off and the battery isolator is engaged.

   Ensure the machine is turned off and the battery isolator is engaged.

2. 2

   If the diagnostic tests reveal a damaged wiring harness or a short to power, repair the affected section of the harness.

   If the diagnostic tests reveal a damaged wiring harness or a short to power, repair the affected section of the harness.

3. 3

   If the heater element itself has failed, replace the entire DEF Suction Line assembly.

   If the heater element itself has failed (which is the most common cause of high resistance), the entire DEF Suction Line assembly must be replaced, as the heater is integrated into the pipe.

4. 4

   Clean the area around the DEF tank and the DEF supply module to prevent dirt ingress.

   Clean the area around the DEF tank and the DEF supply module to prevent dirt ingress.

5. 5

   Disconnect the fluid fittings at the DEF tank and the DEF supply module.

   Disconnect the fluid fittings (typically Voss-style quick connectors) at the DEF tank and the DEF supply module. Have a clean catch pan ready for spilled DEF.

6. 6

   Remove the retention screws/housing and carefully route the new DEF suction line.

   Remove the retention screws/housing and carefully route the new DEF suction line. Ensure it is secured with zip ties or factory clips so it does not chafe against the chassis.

7. 7

   Reconnect the fluid lines and the electrical connector (X579).

   Reconnect the fluid lines and the electrical connector (X579).

8. 8

   Turn the ignition on and use a diagnostic service tool to clear the fault code.

   Turn the ignition on and use a diagnostic service tool to clear the fault code. Alternatively, perform a system reset by turning the ignition off for 60 seconds, then back on.

9. 9

   Run the engine and verify that the DEF system builds pressure and the E4340.03 code does not return.

   Run the engine and verify that the DEF system builds pressure and the E4340.03 code does not return.