P0161

DTC P0141 or P0161 (w/6.0L)

CIRCUIT DESCRIPTION
The heated oxygen sensor (HO2S) must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensor to reach operating temperature. Voltage is provided to the heater by the ignition 1 voltage circuit through a fuse. With the engine running, ground is provided to the heater by the HO2S heater low control circuit, through a low side driver within the powertrain control module (PCM). The PCM commands the heater ON or OFF to maintain a specific HO2S operating temperature range. The PCM determines the temperature by measuring the current flow through the heater. When the heater is in the ON state, the PCM will pulse the heater OFF for a duration of 50 ms, once per second. When the heater is in the OFF state, the PCM will pulse the heater ON for a duration of 50 ms, once per second. The PCM monitors the heater current with the engine running. This diagnostic will only run once per ignition cycle. If the PCM detects that the heater current is not within an expected range, DTC P0141 sets for HO2S bank 1 sensor 2, or DTC P0161 sets for HO2S bank 2 sensor 2.

DTC DESCRIPTORS
This diagnostic procedure supports the following DTCs:
- DTC P0141 HO2S Heater Performance Bank 1 Sensor 2
- DTC P0161 HO2S Heater Performance Bank 2 Sensor 2

CONDITIONS FOR RUNNING THE DTC
- DTCs P0054, P0060, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0169, P0178, P0179, P0200, P0220, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
- The ECT Sensor parameter is greater than 50°C (122°F).
- The Ignition 1 Signal parameter is between 10-18 volts.
- The Fuel Alcohol content parameter is less than 90 percent.
- The MAF Sensor parameter is between 3-40 g/s.
- The Engine Speed parameter is between 500-3,000 RPM.
- The Engine Run Time parameter is more than 300 seconds.
- The above conditions are met for 2 seconds.
- This diagnostic runs one time per drive cycle when the above conditions are met.

CONDITIONS FOR SETTING THE DTC
- The PCM detects that the affected HO2S Heater current parameter is greater than 1.375 amps or less than 0.25 amp.
- The above condition is met for 10 seconds.

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 DESCRIPTION

Step 1 - Step 7:

Step 8 - Step 20:

Step 21 - Step 22:

The number below refers to the step number on the diagnostic table.
7. With no fault present, the test lamp will blink once per second.