DTC P2097: Post Catalyst Fuel Trim System Too Rich

NOTE: 

• Before you troubleshoot, review the general troubleshooting information - Refer to: HOW TO TROUBLESHOOT THE FUEL AND EMISSIONS SYSTEMS or How to Troubleshoot the CVT System(CVT) .
• If any of the DTCs listed below are stored at the same time as DTC P2097, troubleshoot those DTCs first, then recheck for P2097.

  P0133, P1172, P2195, P2A00: A/F sensor (Sensor 1)

  P0134, P0135: A/F sensor (Sensor 1) heater

  P0137, P0138, P0139, P2270: Secondary HO2S (Sensor 2)

  P0141: Secondary HO2S (Sensor 2) heater

  P0171, P0172: Fuel system

  P0201, P0202, P0203, P0204: No. 1 - No. 4 cylinder Fuel injector

  P0300: Random misfire

  P0301, P0302, P0303, P0304: No. 1 - No. 4 cylinder misfire

  P0351, P0352, P0353, P0354: No. 1 - No. 4 cylinder Ignition coil

  P219A: Cylinder A/F variation

DTC (PGM-FI)

1. Problem verification:

   - 1. Turn the vehicle to the ON mode.

   - 2. Clear the DTC with the HDS.

   - 3. Start the engine.

   - 4. Hold the engine speed at 3, 000 rpm without load (CVT in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.

   - 5. Test-drive the vehicle under these conditions:

   • Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
   • CVT in D, M/T in 4th or 5th
   • Engine speed below 4, 000 rpm
   • Drive at a steady speed between 15-75 mph (24-120 km/h) for 70 seconds or more

   Signal	Current conditions
   	Values	Unit
   ECT SENSOR 1
   ENGINE SPEED
   VEHICLE SPEED

   - 6. Monitor the OBD STATUS for DTC P2097 with the HDS.

   DTC Description	OBD STATUS
   P2097 Post Catalyst Fuel Trim System Too Rich

   Does the HDS indicate FAILED?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

   If the HDS 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), secondary HO2S (Sensor 2), and the PCM. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot. If the HDS indicates EXECUTING, keep the test conditions until a result comes on. If the HDS indicates OUT OF CONDITION, go to step 1-5 and recheck.

2. Cylinder A/F variation check:

   - 1. Start the engine.

   - 2. Hold the engine speed at 3, 000 rpm without load (CVT in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.

   - 3. Check under these conditions:

   • A/C off
   • All electrical loads off

   - 4. Do the CYLINDER A/F TEST in the INSPECTION MENU three times with the HDS.

   CYLINDER A/F TEST

   Is the result OK?

   YES 

   Go to step 3.

   NO 

   Go to the troubleshooting for DTC P219A .

3. Exhaust system check:

   - 1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Check for leakage, clogging, or blockage in the exhaust system.

   Is there leakage in the exhaust system between the A/F sensor (Sensor 1) and secondary HO2S (Sensor 2), or any clogging or restrictions in the exhaust system?

   YES 

   Repair or replace the exhaust system .

   NO 

   Go to step 4.

4. A/F sensor (Sensor 1) check (substitution):

   - 1. Substitute a known-good A/F sensor (Sensor 1) .

   - 2. Reconnect all connectors.

   - 3. Turn the vehicle to the ON mode.

   - 4. Clear the DTC with the HDS - Refer to: HOW TO TROUBLESHOOT THE FUEL AND EMISSIONS SYSTEMS or How to Troubleshoot the CVT System(CVT) .

   - 5. Do the PCM idle learn procedure .

   - 6. Start the engine.

   - 7. Hold the engine speed at 3, 000 rpm without load (CVT in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.

   - 8. Test-drive the vehicle under these conditions:

   • Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
   • CVT in D, M/T in 4th or 5th
   • Engine speed below 4, 000 rpm
   • Drive at a steady speed between 15-75 mph (24-120 km/h) for 70 seconds or more

   Signal	Current conditions
   	Values	Unit
   ECT SENSOR 1
   ENGINE SPEED
   VEHICLE SPEED

   - 9. Monitor the OBD STATUS for DTC P2097 with the HDS.

   DTC Description	OBD STATUS
   P2097 Post Catalyst Fuel Trim System Too Rich

   Does the HDS indicate PASSED?

   YES 

   Replace the original A/F sensor (Sensor 1) .

   NO 

   If the HDS indicates FAILED, replace secondary HO2S (Sensor 2) . If the HDS indicates EXECUTING, keep the test conditions until a result comes on. If the HDS indicates OUT OF CONDITION, go to step 4-8 and recheck.