John Deere ECU001209.04 – ECU: Exhaust Pressure Sensor Voltage Low

The Engine Control Unit (ECU) has detected that the voltage from the exhaust pressure sensor is below the expected range, indicating the exhaust manifold pressure signal is out of range low. This fault causes the engine power to be limited and disables the active exhaust filter cleaning function. Continued operation with this active fault may result in a complete loss of machine availability.

• 2032R
• 2038R
• 3032E
• 3033R
• 3035D
• 3038E
• 3039R
• 3043D
• 3046R
• 4044M
• 4044R
• 4052M
• 4052R
• 4066M
• 4066R
• 50G
• 60G
• 75G
• 85G
• 317G
• 325G
• 331G
• 333E
• 333G
• 312GR
• 314G
• 316GR
• 318E
• 318G
• 319E
• 320E
• 320G
• 323E
• 324E
• 324G
• 326E
• 328E
• 329E
• 330G
• 332E
• 332G
• 204L
• 244K
• 244K-II
• 304L
• 324K
• 1570
• 1575
• 1580
• 1585
• 1600 TURBO SERIES III
• 7400A
• 7500A
• 7700A
• 8000A
• 8700A
• 8800A
• 8900A
• 9009A
• Z997R

1. 1

   Visually inspect the exhaust pressure sensor and its electrical connector for any signs of damage, corrosion, or loose connections.

2. 2

   Examine the wiring harness leading to the sensor for any visible damage, such as chafing, breaks, or shorts.

3. 3

   Check the tubes or hoses that connect the exhaust manifold to the pressure sensor for any blockages, kinks, or leaks.

4. 4

   With the key on and engine off, use a multimeter to check the voltages at the sensor's connector (verify the 5-volt supply from the ECU, the sensor ground, and the signal wire). A baseline voltage reading is typically 5V or less.

5. 5

   Use a diagnostic tool like John Deere Service Advisor to read live data from the sensor with the key on and engine off to check for inaccurate baseline readings.

1. 1

   Verify wiring and hoses

   Perform all diagnostic checks to rule out wiring, connection, or hose issues before replacing the sensor.

2. 2

   Replace the exhaust pressure sensor

   If wiring and voltages are correct but the sensor reading is faulty, disconnect the electrical connector and hoses/lines. Unbolt and remove the old sensor from its mounting location on the rocker arm cover. Install the new sensor securely, then reconnect the hoses and connector.

3. 3

   Clear fault codes

   Use a diagnostic tool to clear the ECU001209.04 fault code from the system.

4. 4

   Verify the repair

   Start the engine and let it run to confirm the fault code does not reappear and engine power is restored. Perform a parked exhaust filter cleaning if necessary to ensure full system functionality.