DTC Troubleshooting: P2096, P2097
DTC P2096: Post Catalyst Fuel Trim System Too Lean
DTC P2097: Post Catalyst Fuel Trim System Too Rich
NOTE:
Before you troubleshoot, review the general troubleshooting information.
If any of the DTCs listed below are stored at the same time as DTC P2096 and/or P2097, troubleshoot those DTCs first, then recheck for P2096 or P2097.
P0131, P0132, P0133, P2195: A/F sensor (Sensor 1)
P0134, P0135: A/F sensor (Sensor 1) heater
P0137, P0138, P0139, P2270, P2271: Secondary HO2S (Sensor 2)
P0140, P0141: Secondary HO2S (Sensor 2) heater
P0171, P0172: Fuel system
P0201, P0202, P0203, P0204: No. 1?No. 4 cylinder injector(s)
P0300: Random misfire
P0301, P0302, P0303, P0304: No. 1?No. 4 cylinder misfire
P0351, P0352, P0353, P0354: No. 1?No. 4 cylinder ignition coil(s)
P219C, P219D, P219E, P219F: No. 1?No. 4 cylinder A/F variation

DTC Description
Confirmed DTC
Pending DTC
P2096 Post Catalyst Fuel Trim System Too Lean
    
P2097 Post Catalyst Fuel Trim System Too Rich
    

1.
Problem verification:

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 (in neutral) until the radiator fan comes on, then let it idle.

?5.
Test-drive the vehicle for several minutes in the range of these recorded on-board snapshot parameters:
Engine Speed
Vehicle Speed
ECT Sensor 1
Signal
Current conditions
Values
Unit
Engine Speed
    
Vehicle Speed
    
ECT Sensor 1
    

?6.
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
  

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 1-5 and recheck.?
2.
Exhaust system check:

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
     
     
     
     
NO
     
     
     
Go to step 3.
3.
A/F sensor (Sensor 1) check:

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.


?5.
Do the fuel learn procedure.

?6.
Start the engine.

?7.
Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.

?8.
Test-drive the vehicle for several minutes in the range of these recorded on-board snapshot parameters:
Engine Speed
Vehicle Speed
ECT Sensor 1
Signal
Current conditions
Values
Unit
Engine Speed
    
Vehicle Speed
    
ECT Sensor 1
    

?9.
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
  

Does the HDS indicate PASSED?

     
YES
     
     
     
     
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 3-8 and recheck.?