Diagnostic trouble code (DTC) information

Condition 

Fig 1: Identifying Engine Control Module

Courtesy of VOLVO CARS OF NORTH AMERICA.

After a short delay after ignition has been switched on, a check is performed to check if the heated oxygen sensor (HO2S) guide circuit in the control module is active. Diagnostic trouble code (DTC) ECM-7120 is stored if the control signal in the control module does not vary.

Substitute Value 

Fuel trim is disabled after three restart attempts by the sensor guide circuit.

Possible Source 

Faulty signal: 

• defective sensor guide sensor.

Fault symptom[s] 

None.