Massey Ferguson 000102.12 – ECU: Intake Boost Pressure Sensor Signal Erratic

The Engine Control Unit (ECU) has detected an irregular, unstable, or intermittent signal from the intake boost pressure sensor (often a Manifold Absolute Pressure or MAP sensor). This sensor measures the air pressure in the intake manifold after the turbocharger. An erratic signal means the data sent to the ECU is outside the expected range or pattern, which can lead to incorrect fuel calculations, poor engine performance, and activation of the check engine light. Symptoms can include loss of power, black smoke from the exhaust, rough idling, and the engine entering a derated 'limp mode'.

• 3630 Xtra
• 3640 Xtra
• 3650 Xtra
• 3660 Xtra
• 4607 M
• 4608
• 4609
• 4609 M
• 4610
• 4610 M
• 4707
• 4708
• 4709
• 4710
• 5460
• 5465
• 5470
• 5475
• 5480
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 5710
• 5711
• 5712
• 5713
• 6711R
• 6712R
• 6713R
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7720S
• 7722S
• 7724S
• 7726S
• 8727 S
• 8730 S
• 8735 S
• 8737 S
• 8740 S

1. 1

   Visually inspect the wiring harness and connector going to the intake boost pressure sensor for chafing, corrosion on the pins, loose connections, or breaks in the wires.

2. 2

   Inspect all air intake piping between the turbocharger, the intercooler, and the intake manifold for split hoses, loose clamps, or cracks that could cause pressure to fluctuate.

3. 3

   Check the air filter for severe clogs that could restrict airflow and cause erratic boost pressure readings.

4. 4

   Perform a sensor voltage test by back-probing the connector (ignition on, engine off) to verify a 5-volt reference supply from the ECU, a solid ground, and a signal voltage corresponding to atmospheric pressure (typically 0.5 to 1.5 volts).

5. 5

   Monitor live data with a diagnostic scan tool and compare the sensor's reported pressure with a known-good mechanical boost gauge connected to the intake manifold to verify accuracy under load.

1. 1

   Record and Clear Fault Codes

   Use a diagnostic tool to record any active and stored fault codes, then clear them.

2. 2

   Perform Diagnostic Checks

   Follow the diagnostic checks outlined in the section above.

3. 3

   Address Wiring and Connection Issues

   If any issues are found with the wiring or connector, repair or replace the damaged sections. Ensure the connector is clean and makes a secure connection.

4. 4

   Test Drive

   After any repairs, perform a test drive under various load conditions to see if the fault code returns.

5. 5

   Sensor Replacement (If Necessary)

   If the diagnostic checks point conclusively to a failed sensor, it should be replaced. Disconnect the negative battery terminal, locate the sensor, disconnect the electrical connector, remove the bolt(s) securing the sensor and remove it from the intake manifold. Ensure the mounting surface is clean. Install the new sensor and tighten the retaining bolt(s) to the manufacturer's specified torque. Reconnect the electrical connector and negative battery terminal.

6. 6

   Final Verification

   Clear any remaining fault codes and perform another test drive to confirm the repair has resolved the issue.