DTC P2231
Diagnostic Instructions
DTC Descriptor
DTC P2231 00: HO2S Signal Circuit Shorted to
Heater Circuit Sensor 1
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Heater Voltage Supply
|
P0030 00
|
P0030 00
|
-
|
P0131 5A, P0131 12
|
Reference Voltage Signal
|
P0131 01
|
P0131 12, P2243 00, P2231 00
|
P0131 02, P2231 00
|
P0133 00, P0131 52, P0131 5A, P0132 52,
P0132 5B
|
Pump Current Signal
|
P2626 00
|
P2626 00
|
P2626 00, P2231 00
|
-
|
Trim Current Signal
|
P2626 00
|
P2626 00
|
P2626 00
|
-
|
Heater Low Control
|
P0031 00
|
P0030 00
|
P0032 00
|
-
|
Low Reference
|
P2A00 00
|
P0132 02, P2243 04
|
P0132 02
|
-
|
Circuit/System Description
The wide band heated oxygen sensor (HO2S) measures the
amount of oxygen in the exhaust stream more quickly and accurately
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 signal 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 signal voltage. The ECM monitors the voltage variation on
the signal circuit and attempts to keep the voltage constant by
increasing or decreasing the amount of current flow or reversing
the direction of the current flow to the pumping cell. By measuring
the direction and amount of current required to maintain the signal
voltage, the ECM can determine the concentration of oxygen in the
exhaust. The signal voltage is displayed as a lambda value. A
lambda value of 1 is equal to a stoichiometric air fuel ratio
of 60:1. Under normal operating conditions, the lambda value
will remain around 1. When the system is lean, the oxygen
level will be high and the lambda value will be high, or more
than 1. When the system is rich, the oxygen level is low and
the lambda value will be low, or less than 1. The ECM uses
this information to maintain the proper air/fuel ratio.
Conditions for Running the DTC
• |
The ignition voltage is between 10-18 V. |
• |
The engine speed is greater than 80 RPM. |
• |
The HO2S 1 heater is at operating
temperature. |
• |
DTC P2231 runs continuously when the above
conditions are met. |
Conditions for Setting the DTC
• |
The ECM detects that the HO2S 1 voltage is
more than the threshold. |
• |
DTC P2231 sets within 4 s when the above
condition is met continuously, or within 50 s when the above
condition is met cumulatively. |
Action Taken When the DTC Sets
DTC P2231 is a Type B DTC.
Conditions for Clearing the DTC
DTC P2231 is a Type B 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
- Clear the DTCs with a scan tool.
- Operate the vehicle within the conditions for running
and setting the DTC. The DTC should not set.
- Operate the vehicle within the Conditions for Running
the DTC. You may also operate the vehicle within the conditions
that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Note: You must perform the
Circuit/System Verification before proceeding with Circuit/System
Testing.
- Ignition OFF, disconnect the harness connector at the
B52A Heated Oxygen Sensor 1.
- Ignition ON, test for 2.9 V between the
B52A Heated Oxygen Sensor 1 reference voltage circuit
terminal 6 and ground.
⇒ |
If less than the specified range, test the
reference voltage circuit for a short to ground or an open/high
resistance. If the circuit tests normal, replace the
K20 Engine Control Module. |
⇒ |
If greater than the specified range, test the
reference voltage circuit for a short to voltage. If the circuit
tests normal, replace the K20 Engine Control Module. |
- Test for 2.5 V between the B52A Heated
Oxygen Sensor 1 low reference circuit terminal 2 and
ground.
⇒ |
If less than the specified range, test the low
reference circuit for a short to ground or an open/high resistance.
If the circuit tests normal, replace the K20 Engine Control
Module. |
⇒ |
If greater than the specified range, test the low
reference circuit for a short to voltage. If the circuit tests
normal, replace the K20 Engine Control Module. |
- Test for 2.8 V between the B52A Heated
Oxygen Sensor 1 control circuit terminal 1 and
ground.
⇒ |
If less than the specified range, test the control
circuit for a short to ground or an open/high resistance. If the
circuit tests normal, replace the K20 Engine Control
Module. |
⇒ |
If greater than the specified range, test the
control circuit for a short to voltage. If the circuit tests
normal, replace the K20 Engine Control Module. |
- Test for 2.8 V between the B52A Heated
Oxygen Sensor 1 control circuit terminal 5 and
ground.
⇒ |
If less than the specified range, test the control
circuit for a short to ground or an open/high resistance. If the
circuit tests normal, replace the K20 Engine Control
Module. |
⇒ |
If greater than the specified range, test the
control circuit for a short to voltage. If the circuit tests
normal, replace the K20 Engine Control Module. |
- Ignition OFF, disconnect the X1 harness connector
at the K20 Engine Control Module.
- Test for infinite resistance between each
B52A Heated Oxygen Sensor 1 circuit terminals. If less
than the specified value, repair as necessary.
- If all circuits test normal, replace the
B52A Heated Oxygen Sensor 1 and verify the DTC does not
reset.
⇒ |
If the DTC resets, replace the K20 Engine
Control Module. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|