Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P2A01 (2018 2019)
DTC P2A01 : Secondary HO2S (Sensor 2) Circuit Range/Performance Problem
NOTE: Before you troubleshoot, review the general troubleshooting information .
| DTC Description | Confirmed DTC | Pending DTC |
|---|---|---|
| P2A01 Secondary HO2S (Sensor 2) Circuit Range/Performance Problem |
DTC (PGM-FI)
- 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. Start the engine.
-5. Hold the engine speed at 3, 000 min -1 (rpm) without load (in P or N) until the radiator fan comes on.
-6. Monitor the OBD STATUS for DTC P2A01 in the DTCs MENU with the HDS.
DTC Description OBD STATUS P2A01 Secondary HO2S (Sensor 2) Circuit Range/Performance Problem 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 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 idling until a result comes on. If the HDS indicates OUT OF CONDITION, go to step 1-5 and recheck.
- Determine possible failure area (Secondary HO2S (Sensor 2), others)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connector.
Secondary HO2S (Sensor 2) 4P connector -3. Turn the vehicle to the ON mode.
-4. Check the parameter (s) below with the HDS.
Signal Threshold Current conditions Values Unit Values Unit HO2S S2 Less than 1.26 V Do the current condition (s) match the threshold?
YES
Go to step 3.
NO
- Determine possible failure area (short in SO2 line, short in SO2SG line)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Secondary HO2S (Sensor 2) 4P connector: disconnected Test point 1 Secondary HO2S (Sensor 2) 4P connector (female terminals) No. 1: Test point 2 Body ground Is there continuity?
YES
Go to step 4.
NO
Go to step 5.
- Shorted wire check (SO2 line)
-1. Jump the SCS line with the HDS, and wait more than 1 minute.
-2. Disconnect the following connector.
PCM connector B (51P) -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Secondary HO2S (Sensor 2) 4P connector: disconnected PCM connector B (51P): disconnected Test point 1 Secondary HO2S (Sensor 2) 4P connector (female terminals) No. 1: Test point 2 Body ground Is there continuity?
YES
Repair a short in the SO2 wire between the PCM (B17) and secondary HO2S (Sensor 2).
NO
The SO2 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM .
- Shorted wire check (SO2SG line)
-1. Jump the SCS line with the HDS, and wait more than 1 minute.
-2. Disconnect the following connector.
PCM connector B (51P) -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Secondary HO2S (Sensor 2) 4P connector: disconnected PCM connector B (51P): disconnected Test point 1 Secondary HO2S (Sensor 2) 4P connector (female terminals) No. 2: Test point 2 Body ground Is there continuity?
YES
Repair a short in the SO2SG wire between the PCM (B40) and secondary HO2S (Sensor 2).
NO
The SO2SG wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM .
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.