New Holland ENG 3773 – Engine Control Module (ECM / ECU): Turbocharger: Under boost detected in Pressure charger regulator

The engine control system has detected that the actual intake manifold boost pressure generated by the turbocharger is lower than the target pressure requested by the engine control unit.

• L220
• L223
• L225
• L230
• C232
• C238
• B90B
• B100B
• SR175
• T5.95
• T5.105
• T5.115
• T6
• T7
• T8
• T9
• CR9090
• CX8080
• CX8090 Elevation

1. 1

   Check for related fault codes: Look for code 3794 (Intake air pressure sensor: Plausibility check for air pressure at the upstream of intake valve sensor), which indicates a faulty boost pressure sensor rather than a failed turbocharger.

2. 2

   Inspect the intake system: Check for loose clamps, cracked hoses, or a damaged intercooler between the turbocharger compressor and the intake manifold that could cause boost pressure to leak.

3. 3

   Inspect the exhaust system: Look for exhaust leaks prior to the turbocharger that would prevent the turbine from spooling properly.

4. 4

   Check the EVGT Actuator / Wastegate: Verify that the electronic turbocharger actuator is receiving power and moving freely without mechanical binding.

5. 5

   Verify sensor wiring: Check the wiring harness and connectors for the intake air pressure sensor and the turbocharger actuator for shorts to ground, open circuits, or corrosion.

1. 1

   Connect an Electronic Service Tool (EST) to the machine's diagnostic port and record all active and stored fault codes, including the engine hours at the last occurrence.

2. 2

   Clear the fault codes and operate the machine under load to verify if code ENG 3773 returns.

3. 3

   If the code returns, perform a visual and smoke test of the intake and exhaust systems.

   Repair any leaks found in the charge-air cooler piping or exhaust manifold.

4. 4

   Test the intake air (boost) pressure sensor voltage.

   If the sensor is reading out of range or illogical values compared to atmospheric pressure when the engine is off, replace the boost pressure sensor.

5. 5

   If the sensors and piping are intact, inspect the turbocharger assembly.

   Check the compressor wheel for damage or excessive shaft play.

6. 6

   If the EVGT actuator has failed or the turbocharger is mechanically damaged, replace the turbocharger assembly.

   On many of these models, the electronic actuator and turbocharger are replaced as a single calibrated unit.

7. 7

   After replacing the turbocharger or sensors, clear the codes again and test run the machine to ensure target boost pressures are being met.