John Deere 2659.04 – Engine Control Unit (ECU): EGR Flow Signal Out of Range Low

The EGR flow signal has fallen below the acceptable lower limit, which typically suggests a short to ground in the sensor circuit. Because of this fault, the controller receives falsely low EGR flow readings, disrupting the emissions system, causing a derate, and making active exhaust filter cleaning (regeneration) unavailable.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5090M
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8225R
• 8235R
• 8245R
• 8260R
• 8270R
• 9470RT
• 9520RT
• 9570RT
• S690
• 7760
• 8R Series
• 9RT Series
• S-Series
• 6E Series
• 6M Series
• 6R Series

1. 1

   Connect John Deere Service Advisor (or a compatible scanner) to verify that 2659.04 is active (key on, engine off).

2. 2

   Inspect the EGR Delta Pressure Sensor and its wiring harness for physical damage, corrosion, or obvious shorts to ground. Ensure the connector is seated properly and test each pin for integrity.

3. 3

   Using a multimeter or a John Deere Engine Test Box, probe the power and ground wires at the sensor connector to verify a solid 5-volt reference.

4. 4

   Apply a slight load to the circuit to simulate real-world usage and perform a wiggle test on the harness. The voltage should hold steady; if it drops out, there is a wiring harness issue.

5. 5

   Probe the signal wire. A healthy circuit within spec should read approximately 2.5 volts.

6. 6

   If power, ground, and signal wiring all check out perfectly but the sensor's voltage readings remain unstable or out of range, conclude that the EGR Delta Pressure Sensor has failed internally.

1. 1

   Turn off the engine and remove the key from the ignition.

2. 2

   Locate the EGR Delta Pressure Sensor on the engine.

   Typically mounted near the EGR cooler/valve assembly.

3. 3

   Carefully disconnect the wiring harness connector from the sensor.

4. 4

   Unbolt and remove the faulty sensor from its mounting bracket/ports.

5. 5

   Install the new EGR Delta Pressure Sensor and tighten the mounting hardware to OEM torque specs.

6. 6

   Reconnect the wiring harness, ensuring the connector clicks securely into place.

7. 7

   Connect John Deere Service Advisor (or your diagnostic tool) and clear the ECU fault codes.

8. 8

   Start the engine and perform a system check/test run.

   Ensure the code does not return and that the EGR flow readings are now registering within the normal range.