New Holland ENG 3772 – Engine Control Unit (ECU): Turbocharger: Over boost deviation at P2 too high in Pressure charger regulator.

The engine's control system is detecting that the actual turbocharger boost pressure (measured at the intake manifold/P2) is significantly higher than the target boost pressure commanded by the system. This overboost condition typically points to an inability to vent excess exhaust drive pressure, or a sensor that is falsely reporting high pressure.

• T6.120
• T6.140
• T6.150
• T6.160
• T6.175
• T7.170
• T7.200
• T7.210
• T8030
• TS110A
• TS125A
• TS135A
• CR920
• CR9060
• CR9090
• CX8080
• CX8090
• L-Series
• C-Series
• SR130
• SR160
• SR175
• SV185

1. 1

   Verify the fault code is currently active and not a stored historical code triggered by a temporary glitch.

2. 2

   Inspect the wiring harness and connectors going to the Boost Pressure Sensor (MAP sensor) and the Wastegate Actuator for chafed wires, corrosion, or loose pins.

3. 3

   Perform a sensor plausibility check using a diagnostic tool to read live boost pressure with the engine off (it should read atmospheric pressure; if it reads high, the sensor is faulty).

4. 4

   Inspect the turbocharger wastegate actuator linkage to ensure the rod is not seized, bent, or disconnected.

1. 1

   Clear and Test

   Clear the fault code and run the machine under load to see if the overboost condition returns.

2. 2

   Clean/Replace the Sensor

   If the wiring is intact but the sensor readings are erratic, remove the boost pressure sensor from the intake manifold. Check for severe soot buildup. If cleaning it with a specialized sensor cleaner does not restore accurate readings, replace the sensor.

3. 3

   Test the Actuator

   If the sensor is reading accurately (meaning the engine is genuinely overboosting), test the wastegate actuator. Apply regulated pneumatic pressure (or vacuum, depending on the specific turbo design) directly to the actuator diaphragm using a hand pump.

4. 4

   Free the Linkage or Replace

   If the actuator rod does not move, disconnect the rod from the wastegate lever. If the lever on the turbo is seized, the turbocharger exhaust housing must be cleaned, freed up, or the turbocharger replaced. If the lever moves freely but the actuator does not hold pressure/vacuum, the wastegate actuator has failed and must be replaced.

5. 5

   Reassemble and Verify

   Install the new components, clear the ECU codes, and operate the engine under a heavy load to verify that the P2 boost pressure now matches the commanded target pressure.