Diagnostic Trouble Code (DTC) Information ECM-985C

Condition 

Fig 1: Identifying Internal Atmospheric Pressure Sensor

Courtesy of VOLVO CARS CORPORATION

The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers an internal fault indicating that the internal monitoring functions in the engine control module (ECM) have registered a fault in the analog / digital converter function.

The diagnostic trouble code (DTC) can be diagnosed at ignition on or with the engine running.

Substitute Value 

Engine speed (RPM) and torque are limited to a calculated normal operating range.

Possible Source 

• Damaged engine control module (ECM).

Fault symptom[s] 

• Maximum engine speed (RPM) too low
• Cruise control does not work at all
• Uneven idle
• Malfunction indicator lamp (MIL) lit.