Diagnostic Trouble Code (DTC) Information ECM-243C

Condition 

Fig 1: Identifying Preheating Circuit In Front Lambda Probe

Courtesy of VOLVO CARS CORPORATION

The engine control module (ECM) controls the resistance on the preheating circuit in the front lambda probe. The check is made by the control module measuring the current through the circuit and then converting the current to temperature. The diagnostic trouble code (DTC) is stored and it is interpreted as a fault if the control module detects that the resistance is unreasonably high, which results in a low temperature.

The diagnostic trouble code (DTC) can be diagnosed when driving.

Substitute Value 

• None.

Possible Source 

• Contact resistance and oxidation in the terminals.
• Damaged front heated oxygen sensor (HO2S).

Fault symptom[s] 

• Malfunction indicator light (MIL), on