P0160

Diagnostic Chart:

Schematic:

The heated oxygen (HO2S) bank 2 sensor 2 is threaded into the front exhaust pipe directly behind the cylinder 2, 4, 6 pre-converter (cylinders 2, 4, 6 are closest to radiator). The sensor is used by the ECM to determine the oxygen storage capability of the pre-converter, fuel trim biasing (time held lean or rich) and certain techniques used to diagnose DTCs associated with the pre-catalyst oxygen sensor. The sensor is an electrical source that responds to oxygen content out of the pre-converter. When the sensor reaches approximately 316°C (600°F), it is fully functional and produces a voltage based on the difference in oxygen between the atmosphere and exhaust gas. The ECM sends a 450 mV bias voltage on the signal line, which is pulled up through high resistance. When the HO2S bank 2 sensor 2 is cold, it produces no voltage and has extremely high internal resistance. The internal resistance of the sensor is much greater than the resistance of the bias pull-up resistor. However, when the sensor heats up, it produces voltage that overrides the bias voltage. Under normal conditions, low sensor voltage means high oxygen content/lean air-fuel mixture and vice versa. Normal sensor readings will be around 500-800 mV under steady cruise. DTC P0160 will set if the HO2S bank 2 sensor 2 signal is inactive for a certain length of time.

DTC PARAMETERS
DTC P0160 will set if HO2S bank 2 sensor 2 signal is inactive (not fluctuating outside of the 401 mV to 519 mV range) when:
^ Condition exists for longer than 10 minutes
^ Exhaust pipe moisture has evaporated (calculated engine run time between 0 and 200 seconds), then engine must run for longer than 80 seconds
^ Calculated converter temperature is less than 800°C (1472°F)
^ Main relay voltage is greater than 10.5 seconds

OR

HO2S bank 2 sensor 2 calculated internal resistance is greater than 40k ohms when:
^ Exhaust pipe moisture has evaporated (calculated engine run time between 0 and 200 seconds), then engine must run for longer than 80 seconds
^ Calculated converter temperature is less than 800°C (1472°F)
^ Calculated exhaust gas temperature is greater than 600°C (1112°F)
^ Main relay voltage is greater than 10.5 seconds

DTC P0160 diagnostic runs continuously once the above conditions have been met.

P0160 is a type B DTC

DIAGNOSTIC AIDS

IMPORTANT: If an HO2S bank 2 sensor 2 heater circuit or heater performance DTC is also set, diagnose that DTC first. An inoperative heater will slow down sensor activation time and may set this DTC.

To locate an intermittent problem, use Scan tool to monitor HO2S BANK 2 SENSOR 2 voltage with engine running at normal operating temperature. Bias voltage (450 mV) will appear on the Scan tool if there is an open anywhere in the sensor circuit.