Diagnostic Trouble Code (DTC) Information ECM-999D

Condition 

Fig 1: Identifying Internal Atmospheric Pressure Sensor

Courtesy of VOLVO CARS CORPORATION

The engine control module (ECM) continuously checks the internal reset functionality in the engine control module (ECM). The diagnostic trouble code (DTC) is stored in the event of a fault in the reset function.

The diagnostic trouble code (DTC) is diagnosed when the ignition is on.

Substitute Value 

The engine control module (ECM) tries to reset the engine control module (ECM).

Possible Source 

• Faulty software in the engine control module (ECM)
• Damaged engine control module (ECM).

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit
• The malfunction indicator lamp (MIL) flashes
• The engine cuts out
• The starter motor turns but the engine does not start.