DTC P0159: 2/2 O2 Sensor Slow Response: Description

The 2/2 HO2S slow response is monitored when engine is running at idle. On first part of test, if limits are exceeded, test passes. If first test does not pass, second part of test is performed when engine is running at idle, Ambient/Battery Temperature Sensor (BTS) is more than 44°F (7°C), barometric pressure is more than 22.13 in. H2O, battery voltage is more than 10.5 volts, MAP sensor reading is 11.79-18.15 in. H2O, engine speed is 1350-2200 RPM and vehicle speed is 50-65 MPH. DTC P0159 may be stored in PCM if 2/2 HO2S signal voltage is switching from less than .39 volt to more than .58 volt and back fewer times than required.

Possible causes are:

• Intermittent Condition
• Exhaust Leak
• 2/2 HO2S Signal Circuit Voltage Drop
• 2/2 HO2S Ground Circuit Voltage Drop
• Faulty 2/2 HO2S