DTC P2A00: A/F Sensor (Sensor 1) Range/Performance Problem

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Turn the ignition switch to ON (II).
Clear the DTC with the HDS.
Start the engine. Hold the engine speed at 3, 000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.
Test-drive under these conditions:
- Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
- Transmission in D
- Vehicle speed at 26 mph (41 km/h) or more, and engine speed at 3, 250 rpm or less
- Drive with the throttle fully opened for 5 seconds from an engine speed of 1, 600 rpm, then slow down with the throttle completely closed.
Monitor the OBD STATUS for DTC P2A00 in the DTCs MENU with the HDS.
Does the screen indicate FAILED?

YES -Go to step 6.

NO -If the screen indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the PCM. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, Go to step 3 and recheck.
Turn the ignition switch to LOCK (0).
Replace the A/F sensor (Sensor 1) (see A/F SENSOR REPLACEMENT ).
Turn the ignition switch to ON (II).
Reset the PCM with the HDS.
Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
Test-drive under these conditions:
- Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
- Transmission in D
- Vehicle speed at 26 mph (41 km/h) or more, and engine speed at 3, 250 rpm or less
- Drive with the throttle fully opened for 5 seconds from an engine speed of 1, 600 rpm, then slow down with the throttle completely closed.
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P2A00 indicated?

YES -Check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the PCM, then Go to step 1.

NO -Go to step 13.
Monitor the OBD STATUS for DTC P2A00 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?

YES -Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 12, go to the indicated DTC's troubleshooting.

NO -If the screen indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the PCM, then Go to step 1. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, Go to step 10.