Diagnostic Instructions
DTC Descriptors
DTC P167A: Control Module HO2S Bank 1 Sensor 1 System Performance
Circuit/System Description
The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The
exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic
circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing
or decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust. The HO2S voltage is
displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1. When the fuel system is lean, the oxygen level will be high and the
lambda signal will be high or more than 1. When the fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air/fuel ratio.
Conditions for Running the DTC
| • | The engine is operating. |
| • | The ignition voltage is between 11-18 volts. |
| • | DTC P167A runs continuously once the above conditions are met for 10 seconds. |
Conditions for Setting the DTC
| • | There is an internal ECM condition with the integrated circuits for HO2S 1 |
| • | The above condition exists for greater than 4 seconds. |
Action Taken When the DTC Sets
DTC P167A is a Type C DTC.
Conditions for Clearing the DTC
DTC P167A is a Type C DTC.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
Circuit/System Verification
- Ignition ON, observe the scan tool DTC information. Verify no other DTCs are set.
- Engine idling at operating temperature for at least 30 seconds. Observe the scan tool DTC information. DTC P167A should not set.
| ⇒ | If DTC P167A sets, replace the ECM. |
- Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for engine control module replacement, setup, and programming
