Oxygen sensor circuit malfunction

P0130 - upstream of catalyst (front) / rear (RH) bank

P0136 - upstream of catalyst (middle) / rear (RH) bank

P0150 - upstream of catalyst (front) / front (LH) bank

Emissions Equipment Information

Three o² sensor system (KL engine with one catalytic converter) - A front sensor is positioned on the LH bank and a middle sensor is positioned on the RH bank upstream of the catalyst for closed loop fuel control.  A rear sensor is mounted downstream of the catalyst to monitor its efficiency.

Four o² sensor system (KJ / KL engine with three catalytic converters) - Front sensors are mounted upstream of the RH and LH warm-up three-way catalyst (WU-TWC) for closed loop fuel control.  Rear sensors are mounted downstream of the WU-TWCs to monitor their efficiency.

Detection Conditions

• The ECU monitors the inversion cycle period, lean-to-rich response time, and the rich-to-lean response time of the upstream oxygen sensors and calculates the average inversion cycle period and the average response time.  If any exceeds the preprogrammed threshold, the ECU determines that the oxygen sensor is malfunctioning under the following monitoring conditions:
  • DRIVE MODE 3

Diagnostic Support Notes

• This is an intermittent monitor (CATALYST)
• Check engine indicator illuminates if the ECU detects either of the above malfunction conditions in two consecutive drive cycle
• DIAGNOSTIC MONITORING TEST RESULTS available
• PENDING CODE is not available
• FREEZE FRAME DATA is available
• DTC is stored in ECU memory

Possible Causes

• Oxygen sensor deterioration
• Oxygen sensor heater circuit malfunction
• Fuel pressure regulator control (PRC) solenoid valve malfunction
• Fuel pressure regulator malfunction
• Fuel pump malfunction
• Fuel filter restriction
• Fuel leakage from fuel line, fuel distribution pipe, fuel pump
• Fuel return hose line restriction
• Exhaust system leak
• Purge solenoid valve malfunction
• Purge solenoid hoses misrouted
• Insufficient engine compression
• Engine malfunction

[P0130 / P0136 / P0150 - From 2002 Mazda Millenia factory service manual]