DTC P2A00: A/F Sensor (Sensor 1) Circuit 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 (A/T in P or N, M/T in neutral) 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)
- A/T in D, M/T in 3rd
- Vehicle speed between 25-55 mph (40-88 km/h) for 5 minutes
- Drive at a steady speed between 55-75 mph (88-120 km/h) for 10 seconds, then decelerate (with the throttle fully closed) for 5 seconds
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 ECM/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 ECM/PCM with the HDS.
Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
Start the engine. Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) 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)
- A/T in D, M/T in 3rd
- Vehicle speed between 25-55 mph (40 - 88 km/h) for 5 minutes
- Drive at a steady speed between 55-75 mph (88-120 km/h) for 10 seconds, then decelerate (with the throttle fully closed) for 5 seconds
Check for Temporary DTCs or 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 ECM/PCM, then go to step 1.

NO -Go to step 14.
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 Temporary DTCs or DTCs were indicated in step 13, go to the indicated DTCs troubleshooting.

NO -If the screen indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the ECM/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 11.