Diagnostic Trouble Code (DTC) Information ECM-985A

Condition 

Fig 1: Identifying Internal Atmospheric Pressure Sensor

Courtesy of VOLVO CARS OF NORTH AMERICA.

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 one or more present values that do not correspond with the compliment value. The diagnostic trouble code (DTC) is diagnosed at ignition on or with the engine running.

Substitute Value 

The 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.