Diagnostic Trouble Code (DTC) Information ECM-640D

Condition 

The engine control module (ECM) checks the boost pressure. The diagnostic trouble code (DTC) is stored if the ratio between the measured boost pressure (measured value from the boost pressure sensor before the throttle) and the calculated boost pressure (calculated value after the throttle) is incorrect.

The diagnostic trouble code (DTC) can be diagnosed when the turbocharger (TC) control system is active.

Substitute Value 

• Reduced boost pressure.

Possible Source 

• Damaged boost pressure sensor
• Loose boost pressure sensor (the engine control module (ECM) measures the atmospheric pressure)
• Air leakage downstream of the turbocharger (TC) (between the turbocharger (TC) and the electronic throttle unit)
• Large air leak at the intake manifold (after the electronic throttle unit).

Fault symptom[s] 

• Poor performance.