DTC P2096, P2097

DTC P2096  : Post Catalyst Fuel Trim System Too Lean

DTC P2097  : Post Catalyst Fuel Trim System Too Rich

DTC (PGM-FI)

1. Problem verification

   -1. Turn the vehicle to the ON mode.

   -2. Clear the DTC with the HDS.

   -3. Turn the vehicle to the OFF (LOCK) mode.

   -4. Enter the maintenance mode, then start the engine .

   -5. Hold the engine speed at 3000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.

   -6. Test-drive the vehicle under these conditions:

   • Engine coolant temperature (ECT SENSOR 1) above 158 deg.F (70 deg.C)
   • Transmission in D
   • Engine speed below 4000 RPM
   • Drive at a steady speed between 15-75 mph (24-120 km/h) for 80 seconds or more

   Signal	Current conditions
   	Values	Unit
   ECT Sensor 1
   Engine Speed
   Vehicle Speed

   Data List

   -7. Monitor the OBD STATUS for DTC P2096 and/or P2097 with the HDS.

   DTC Description	OBD STATUS
   P2096 Post Catalyst Fuel Trim System Too Lean
   P2097 Post Catalyst Fuel Trim System Too Rich

   OBD Status

   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 on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the 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 1-6 and recheck.

2. Cylinder A/F variation check

   -1. Enter the maintenance mode, then start the engine .

   -2. Hold the engine speed at 3000 RPM without load (in P or N) 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 Function Test 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

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

   -2. Reconnect all connectors.

   -3. Turn the vehicle to the ON mode.

   -4. Reset the PCM with the HDS .

   Reset PCM

   -5. Enter the maintenance mode, then start the engine .

   -6. Hold the engine speed at 3000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.

   -7. Test-drive the vehicle under these conditions:

   • Engine coolant temperature (ECT SENSOR 1) above 158 deg.F (70 deg.C)
   • Transmission in D
   • Engine speed below 4000 RPM
   • Drive at a steady speed between 15-75 mph (24-120 km/h) for 80 seconds or more

   Signal	Current conditions
   	Values	Unit
   ECT Sensor 1
   Engine Speed
   Vehicle Speed

   Data List

   -8. Monitor the OBD STATUS for DTC P2096 and/or P2097 with the HDS.

   DTC Description	OBD STATUS
   P2096 Post Catalyst Fuel Trim System Too Lean
   P2097 Post Catalyst Fuel Trim System Too Rich

   OBD Status

   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 4-7 and recheck.