P0523
DTC P0523: EOP Sensor Circuit High Voltage1. Reset the ECM with the HDS.
2. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
3. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0523 indicated?
YES - Go to step 4.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the EOP sensor and the ECM.
4. Turn the ignition switch OFF.
5. Disconnect the EOP sensor 3P connector.
6. Turn the ignition switch ON (II).
7. Measure voltage between EOP sensor 3P connector terminal No.2 and body ground.
Is there about 5 V?
YES - Go to step 8.
NO - Go to step 10.
8. Measure voltage between EOP sensor 3P connector terminal No.1 and body ground.
Is there about 5 V?
YES - Go to step 9.
NO - Repair open in the wire between the ECM (A20) and the EOP sensor.
9. Measure voltage between EOP sensor 3P connector terminals No.1 and No.3.
Is there about 5 V?
YES - Go to step 15.
NO - Repair open in the wire between the ECM (A10) and the EOP sensor.
10. Turn the ignition switch OFF.
11. Wait for 1 minute. If the radiator fan is running, wait for 1 minute after it stops.
12. Disconnect ECM connector C (22P).
13. Connect EOP sensor 3P connector terminal No.2 to body ground with a jumper wire.
14. Check for continuity between ECM connector terminal C3 and body ground.
Is there continuity?
YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
NO - Repair open in the wire between the ECM (C3) and the EOP sensor.
15. Substitute a known-good EOP sensor, then recheck.
16. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0523 indicated?
YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
NO - Replace the EOP sensor.