JCB P3414-87 – Aftertreatment system ECU: Erroneous Signal for Engine Boost Pressure

The Aftertreatment system ECU has detected an abnormal or irrational signal from the engine's boost pressure sensor. This indicates that the data related to the engine's boost pressure is incorrect or out of the expected range, pointing to a problem with the component responsible for generating or transmitting this signal rather than a completely missing message.

• Machines equipped with EcoMAX Tier 4 engines
• Tracked Excavators
• Wheeled Excavators

1. 1

   Visually inspect the wiring harness and connectors associated with the boost pressure sensor for any signs of damage, corrosion, loose connections, rubbing, or excessive heat

2. 2

   Disconnect and inspect the pins and terminals of the boost pressure sensor and the corresponding ECU connector for debris, water ingress, or poor sealing (often a consequence of pressure washing)

3. 3

   Check for any damaged or loose machine earth connections, as this can affect sensor readings

4. 4

   Perform a general check of the CAN bus network integrity, as the Aftertreatment ECU communicates via the CAN bus

1. 1

   Safety preparation

   Stop the engine and allow it to cool completely before commencing any work.

2. 2

   Access the sensor

   Locate the engine boost pressure sensor. On many diesel engines, this sensor is mounted on the intake manifold.

3. 3

   Repair harness and connectors

   Thoroughly inspect the wiring and connectors between the boost pressure sensor and the Aftertreatment ECU. Repair any chafed or broken wires and clean any corroded connectors. Ensure a secure connection upon reassembly.

4. 4

   Test the sensor

   If equipped with a typical 3-wire boost pressure sensor, test it with the key on and engine off. You should measure a 5-volt reference and a good ground at the connector. The signal voltage should vary with pressure.

5. 5

   Replace the component

   If the wiring and connectors are in good condition and the sensor fails testing or is suspected to be faulty, replace the boost pressure sensor.

6. 6

   Clear fault codes

   After the repair, use a suitable diagnostic tool, such as JCB ServiceMaster, to clear the fault codes.

7. 7

   Verify repair

   Start the engine and check if the fault code reappears to confirm the fix.