DTC Troubleshooting: P0523 (22)
DTC P0523:
 EOP Sensor Circuit High Voltage
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
  1. Turn the ignition switch ON (II).
  1. Check the EOP SENSOR in the DATA LIST with the HDS.
Is there about 4.79 V or more?
YES -
Go to Step 3 .
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the EOP sensor and the ECM.■
  1. Turn the ignition switch OFF.
  1. Disconnect the EOP sensor 3P connector.
  1. Connect EOP sensor 3P connector terminals No. 2 and No. 3 with a jumper wire.
  1. Turn the ignition switch ON (II).
  1. Check the EOP SENSOR in the DATA LIST with the HDS.
Is there about 4.79 V or more?
YES -
Go to Step 8 .
NO -
Go to Step 18 .
  1. Remove the jumper wire.
  1. Measure voltage between EOP sensor 3P connector terminals No. 1 and No. 3.
Is there about 5 V?
YES -
Go to Step 14 .
NO -
Go to Step 10 .
  1. Turn the ignition switch OFF.
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM connector C (44P).
  1. Check for continuity between ECM connector terminal C14 and EOP sensor 3P connector terminal No. 3.
Is there continuity?
YES -
Go to Step 26 .
NO -
Repair open in the wire between the ECM (C14) and the EOP sensor, then go to Step 20 .
  1. Turn the ignition switch OFF.
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM connector C (44P).
  1. Check for continuity between ECM connector terminal C22 and EOP sensor 3P connector terminal No. 2.
Is there continuity?
YES -
Go to Step 26 .
NO -
Repair open in the wire between the ECM (C22) and the EOP sensor, then go to Step 20 .
  1. Turn the ignition switch OFF.
  1. Reconnect all connectors and the battery.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0523 indicated?
YES -
Check for poor connections or loose terminals at the EOP sensor and the ECM, then go to Step 1 .
NO -
Go to Step 25 .
  1. Monitor the OBD STATUS for DTC P0523 in the DTCs MENU with the HDS.
Does the screen indicated PASSED?
YES -
Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in Step 24 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the EOP sensor and the ECM, then go to Step 1 . If the screen indicates NOT COMPLETED, go to Step 23 .
  1. Reconnect all connectors.
  1. Start the engine.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0523 indicated?
YES -
Check for poor connections or loose terminals at the EOP sensor and the ECM. If the ECM was updated, substitute a known-good ECM, then go to Step 28 . If the ECM was substituted, go to Step 1 .
NO -
Go to Step 30 .
  1. Monitor the OBD STATUS for DTC P0523 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. If any other Temporary DTCs or DTCs were indicated in Step 29 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the EOP sensor and the ECM. If the ECM was updated, substitute a known-good ECM, then go to Step 28 . If the ECM was substituted, go to Step 1 . If the screen indicates NOT COMPLETED, keep idling until a result comes on.