DTC Troubleshooting: P2237, P2238
DTC P2237: A/F Sensor (Sensor 1) Malfunction
DTC P2238: A/F Sensor (Sensor 1) Malfunction
NOTE: Before you troubleshoot, review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
P2237 A/F Sensor (Sensor 1) Malfunction
    
P2238 A/F Sensor (Sensor 1) Malfunction
    

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.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
P2237 A/F Sensor (Sensor 1) Malfunction
    
P2238 A/F Sensor (Sensor 1) Malfunction
    

Is DTC P2237 and/or P2238 indicated?

     
YES
     
     
     
The failure is duplicated. Go to step 2.
     
NO
     
     
     
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 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.?
2.
A/F sensor (Sensor 1) check:

A/F sensor (Sensor 1) check
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Substitute a known-good A/F sensor (Sensor 1).

?3.
Reconnect all connectors.

?4.
Turn the vehicle to the ON mode.

?5.
Clear the DTC with the HDS.


?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.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
P2237 A/F Sensor (Sensor 1) Malfunction
    
P2238 A/F Sensor (Sensor 1) Malfunction
    

Is DTC P2237 and/or P2238 indicated?

     
YES
     
     
     
Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. If DTC P2237 and/or P2238 goes away and the PCM was substituted, replace the original PCM.?
     
NO