P0159
DTC P0159
CIRCUIT DESCRIPTION
The heated oxygen sensor (HO2S) produces a voltage that varies between 100-900 mV under normal operating conditions. The engine control module (ECM) produces a bias voltage on the HO2S signal circuit of 420-480 mV. The reference ground for the sensor is provided through the ECM. The ECM monitors the signal voltage to determine if the exhaust is lean or rich. The oxygen sensor voltage is high when the exhaust is rich, and low when the exhaust is lean. The ECM constantly monitors the HO2S signal during the Closed Loop operation. If the ECM detects that the decel fuel cut-off rich-to-lean transition time is too long, DTC P0139 will set for bank 1 sensor 2, or DTC P0159 will set for bank 2 sensor 2.
DTC DESCRIPTORS
This diagnostic procedure supports the following DTCs:
- DTC P0139 HO2S Slow Response Bank 1 Sensor 2
- DTC P0159 HO2S Slow Response Bank 2 Sensor 2
CONDITIONS FOR RUNNING THE DTC
- DTCs P0021, P0024, P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0135, P0137, P0138, P0139, P0140, P0141, P0151, P0152, P0155, P0157, P0158, P0159, P0160, P0161, P0201-P0208, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0279, P0280, P0282, P0283, P0300, P0301-P0308, P0335, P0336, P0340, P0341, P0345, P0346, P0351-P0358, P0365, P0366, P0390, P0391, P0442, P0443, P0446, P0449, P0453, P0454, P0455, P0458, P0459, and P0496 are not set.
- The ECT Sensor parameter is more than 66°C (151°F).
- The Vehicle Speed Sensor parameter is between 5-180 km/h (3-112 mph).
- The calculated catalytic converter temperature is more than 520°C (968°F).
- DTC P0139 or P0159 runs continuously once the above conditions are met.
CONDITIONS FOR SETTING THE DTC
The ECM detects that the decel fuel cut-off and rich-to-lean transition time has exceeded 1 second.
ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.
TEST
