DTC P2A00: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Range/Performance Problem: General Description
The air/fuel ratio (A/F) sensor has a linear signal output in relation to the oxygen concentration. The engine control module (ECM) computes the air/fuel ratio from A/F sensor output voltage and uses the fuel feedback control to improve exhaust emissions. The ECM monitors A/F sensor output voltage during deceleration with the throttle fully closed, and it detects a malfunction and stores a DTC if the output voltage deviates greatly from normal oxygen concentration levels.
* Output to the scan tool exhibits a relationship between the A/F sensor output and oxygen concentration, which is opposite to the characteristic shown in the graph. That is, a deviation toward the rich side increases the output voltage and one toward the lean side decreases the output voltage as the stoichiometric ratio is 0.
MONITOR DESCRIPTION CHART
| Execution |
Once per driving cycle |
| Sequence |
None |
| Duration |
3.1 seconds or more |
| 3.15 - 6.45 seconds |
| DTC Type |
Two drive cycles, MIL ON |
ENABLE CONDITIONS CHART
| Condition |
Minimum |
Maximum |
| Elapsed time after starting the engine |
60 seconds |
- |
| Engine coolant temperature |
158°F (70°C) |
- |
| Intake air temperature |
-14°F (-25°C) |
- |
| Engine speed |
- |
2,700 rpm |
| 1,050 rpm |
| Vehicle speed |
30 mph (48 km/h) |
- |
| 16 mph (10 km/h) |
| Fuel feedback |
During deceleration |
| Monitoring priority |
Catalyst System, EVAP |
| No active DTCs |
ECM, A/F Sensor, A/F Sensor Heater, CKP, TP, BARO, VSS, Fuel System, EVAP, A/T System |
| Other |
Other than when there is excessive vapor generation (fuel level is 40 - 80%) |