LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Acura >> 2009 >> TL Base >> Repair and Diagnosis >> Engine Performance >> System >> PGM-FI System >> DTC Troubleshooting >> DTC P1172: Rear A/F Sensor (Bank 1, Sensor 1) Circuit Out of Range High; DTC P1174: Front A/F Sensor (Bank 2, Sensor 1) Circuit Out of Range High
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P1172: Rear A/F Sensor (Bank 1, Sensor 1) Circuit Out of Range High; DTC P1174: Front A/F Sensor (Bank 2, Sensor 1) Circuit Out of Range High

NOTE:
  • Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
  • Information marked with an asterisk (*) applies to the front bank (Bank 2).
  1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
  2. Clear the DTC with the HDS.
  3. 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.
  4. Monitor the OBD STATUS for P1172 and/or P1174* in the DTCs MENU with the HDS.

    Does the screen indicate FAILED? 

    YES  -Go to step 5.

    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.

  5. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
  6. Replace the A/F sensor (Sensor 1) (see A/F SENSOR REPLACEMENT  ).
  7. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
  8. Reset the ECM/PCM with the HDS.
  9. Do the ECM/PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  10. 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.
  11. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P1172 and/or P1174* 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 12.

  12. Monitor the OBD STATUS for DTC P1172 and/or P1174* 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  11, 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 ECM/PCM, then go to step  1. If the screen indicates EXECUTING keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step  10.

scientia non olet · About LEMON Manuals