What this code means
P0523 means the ECM/PCM may be seeing the engine oil pressure sensor signal as higher than expected.
What the vehicle may do
- The check engine light may be on.
- The vehicle may store the fault when the sensor signal is interpreted as high.
Possible fault areas
- A possible engine oil pressure sensor signal issue.
- A possible connector or wiring issue in the sensor circuit.
- A possible ECM/PCM issue after the related checks pass.
Diagnostic path
Opening and code context
On this 2020 to 2025 Honda CR-V Hybrid, P0523 is an engine oil pressure sensor circuit high-voltage fault. In plain terms, the ECM/PCM may be seeing the rocker arm oil pressure sensor signal higher than expected. The vehicle may turn on the check engine light, and the fault can involve the sensor signal, the sensor ground side, connector or wiring issues, or, after the circuit checks pass, a possible ECM/PCM issue. Start with the basic system checks and follow a structured diagnostic approach before getting into the pinpoint testing.
Confirm the fault
First, reproduce the operating condition. Turn the vehicle to the ON mode and watch the HDS value for Rocker Arm Oil Pressure, EOP, Sensor Voltage. If that value is more than 4.79 V, the failure is duplicated. That is the high-voltage condition this diagnostic path is built around.
Check sensor-side response
Next, move into the engine oil pressure sensor inspection. There is not a direct standalone way to test the component itself here, so the procedure checks the related circuit response. Disconnect the engine oil pressure sensor connector, the 3P connector. Then jump terminals No. 1 and No. 2 of that sensor connector with a jumper wire. Turn the vehicle back to the ON mode and confirm the HDS Rocker Arm Oil Pressure, EOP, Sensor Voltage again. The normal condition for this check is less than 4.79 V. If the reading is normal during this jumper check, the circuit can respond correctly and the problem is with the engine oil pressure sensor. If it is not normal, keep going into the related circuit checks instead of guessing at the sensor.
Check OPSEN and SG2 for opens
If the sensor-side response was abnormal, check the OPSEN and SG2 circuits for an open. Before disconnecting the PCM connector, jump the SCS line with the HDS and wait more than 1 minute. Then disconnect the engine oil pressure sensor 3P connector and disconnect PCM connector B, the 101P connector. Perform the OPSEN and SG2 open-wire checks using the correct connector and terminal information. The normal condition is less than 1 Ω on the OPSEN open-wire inspection, and less than 1 Ω on the SG2 open-wire inspection. If either check is abnormal, the problem is in the circuit. If you do not have the terminal identification needed for this part of the test, stop and recheck the earlier diagnostic path rather than probing by guesswork.
PCM decision point
If the engine oil pressure sensor inspection and the OPSEN and SG2 circuit checks all indicate normal conditions, the remaining conclusion in this path is a problem with the PCM. Treat that as the end of the diagnostic logic, not as a shortcut. The earlier checks have to be clean before you make that call.
Verification and takeaway
Keep the verification separate from the testing. After correcting the fault that the diagnostic path identifies, verify the repair and confirm P0523 stays gone. The key takeaway is simple: confirm the high sensor voltage first, prove whether the sensor-side signal can be pulled below the threshold, then check OPSEN and SG2 continuity before blaming the PCM. For more diagnostic training, visit stepdiagnostics.com.
Final check
P0523 is often approached as an electrical sensor-circuit diagnosis: confirm the high signal, test the related circuit response, then isolate whether the fault points to the sensor circuit or the PCM.
For more guided automotive diagnostics, visit STEP Diagnostics.
