DTC P0137, DTC P0138 & DTC P0140: Condition

DTC is set when Heated Oxygen Sensor (HO2S) No. 2 maximum output voltage is lower than predetermined or minimum output voltage is higher than predetermined while driving vehicle. DTC is also set when HO2S No. 2 output voltage is 4.5 volts or more with engine at normal operating temperature. HO2S No. 2 circuit is monitored once per drive cycle. MIL is illuminated when Engine Control Module (ECM) detects malfunction during 2 consecutive drive cycles. Possible causes are:

• Exhaust system leak.
• Open or short to ground in circuit between HO2S No. 2 and ECM.
• HO2S No. 2 malfunction.
• Fuel system malfunction.
• Low fuel level.