Diagnostic Trouble Code (DTC) Information ECM-24CD

Condition 

Fig 1: Front Heated Oxygen Sensor

Courtesy of VOLVO CARS CORPORATION

The engine control module (ECM) monitors the operation of the heated oxygen sensor (HO2S) by checking its signal. The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers any of the following.

• The engine control module (ECM) compares the front and rear heated oxygen sensor (HO2S) adaptation values. The diagnostic trouble code (DTC) is stored when the values deviate by more than 3%.
  NOTE:

  The fault may be in the front or rear heated oxygen sensor (HO2S) circuit.

• The signal from the front heated oxygen sensor (HO2S) indicates a lean fuel/air mixture. The signal from the rear heated oxygen sensor (HO2S) indicates a rich fuel/air mixture
• The signal from the front heated oxygen sensor (HO2S) indicates a rich fuel/air mixture. The signal from the rear heated oxygen sensor (HO2S) indicates a lean fuel/air mixture
• The signal from the heated oxygen sensor (HO2S) indicates an incorrectly rich/lean fuel/air mixture compared to what is expected by the engine control module (ECM).

Substitute Value 

• The heated oxygen sensor (HO2S) control is disabled
• Three-way catalytic converter (TWC) diagnostics are disabled.

Possible Source 

• Leakage in the exhaust system
• Heated oxygen sensor (HO2S) indicates an incorrectly rich fuel/air mixture
• Damaged heated oxygen sensor (HO2S).

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.