DTC P2A00
Diagnostic Instructions
DTC Descriptors
| DTC P2A00 53: HO2S Circuit Closed Loop
Performance Bank 1 Sensor 1 Malfunction |
| DTC P2A00 54: HO2S Circuit Closed Loop
Performance Bank 1 Sensor 1 Malfunction |
Circuit/System Description
The two heated oxygen sensors (HO2S) are used for fuel control
and catalyst monitoring. Each HO2S compares the oxygen content of
the surrounding air with the oxygen content of the exhaust stream.
When the engine is started, the control module operates in an Open
Loop mode, ignoring the HO2S signal voltage while calculating the
air-fuel ratio. While the engine runs, the HO2S heats up and begins
to generate a voltage within a range of 0-1 275 mV. Once sufficient
HO2S voltage fluctuation is observed by the control module, Closed
Loop is entered. The control module uses the HO2S voltage to
determine the air-fuel ratio. An HO2S voltage that increases toward
1 000 mV indicates a rich fuel mixture. An HO2S voltage that
decreases toward 0 mV indicates a lean fuel mixture.
Conditions for Running the DTC
| • |
DTCs P0106, P0107, P0108,
P0116, P0117, P0118, P0131, P0132, P0201, P0202, P0203, P0204,
P1516, P2101, P2119, or P2176 are not set. |
| • |
Ignition voltage is between
10-18 V. |
| • |
Engine speed is between 1
000-3 400 RPM. |
| • |
Airflow into the engine is
between 4-30 g/s. |
| • |
Engine coolant temperature
(ECT) is greater than 70°C (158°F). |
| • |
Engine run time is greater
than 100 s. |
| • |
DTC P2A00 runs continuously
when the above conditions are met for greater than 5 s.
|
Conditions for Setting the DTC
The ECM detects that the HO2S 1 voltage is greater than 1 100 mV
for greater than 20 s after closed loop is enabled.
Action Taken When the DTC Sets
DTC P2A00 is a Type B DTC.
Conditions for Clearing the DTC
DTC P2A00 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
| 1. |
Ignition ON, observe the DTC
information with a scan tool. DTC P0030, P0053, P0131, P0132, P0134
or P0135 should not be set. |
| 2. |
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 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.
| 1. |
Ignition OFF, disconnect the
harness connector at the B52 Heated Oxygen Sensor. |
| 2. |
Ignition ON, test for 2.9 V
between the B52 Heated Oxygen Sensor 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. |
| 3. |
Test for 2.5 V between the B52
Heated Oxygen Sensor 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. |
| 4. |
Test for 2.8 V between the B52
Heated Oxygen Sensor 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. |
| 5. |
Test for 2.8 V between the B52
Heated Oxygen Sensor 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. |
| 6. |
Ignition OFF, disconnect the
X1 harness connector at the K20 Engine Control Module. |
| 7. |
Test for infinite resistance
between each B52 Heated Oxygen Sensor circuit terminals.
|
| ⇒ |
If less than the specified value, repair as
necessary. |
| 8. |
If all circuits test normal,
replace the B52 Heated Oxygen Sensor 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.
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