Diagnostic trouble code (DTC) information

Condition 

Fig 1: Identifying Engine Coolant Temperature (ECT) Sensor

Courtesy of VOLVO CARS OF NORTH AMERICA.

Diagnostic trouble code (DTC) ECM-A0 is stored if the control module detects rapid changes in the engine coolant temperature (ECT).

Substitute Value 

• No fuel trim
• Limited EVAP control
• No three-way catalytic converter (TWC) diagnostic.

Possible Source 

• Defective engine coolant temperature (ECT) sensor
• Contact resistance in the terminals.

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit
• High fuel consumption.