Low Oil Pressure Indicator Circuit Troubleshooting (Open)
  1. Turn the ignition switch ON (II).
  1. Make sure the HDS communicates with the vehicle and the engine control module (ECM). If it doesn't, troubleshoot the DLC circuit.
  1. Check for DTCs. If a DTC is present, diagnose, and repair the cause before continuing with this test.
  1. Turn the ignition switch ON (II), select DIESEL system, and check the OIL PRESSURE SWITCH in the DATA LIST with the HDS.
Is ‘‘ON'' indicated?
YES -
NO -
Go to Step 6 .
Is the oil pressure switch OK?
YES -
Go to Step 7 .
NO -
  1. Turn the ignition switch ON (II), and jump the SCS line with the HDS, then turn the ignition switch OFF.
    NOTE: This step must be done to protect the ECM from damage.
  1. Disconnect ECM connector No. 2 (58P) and the oil pressure switch connector.
  1. Check for continuity between ECM connector No. 2 terminal No. 58 and the oil pressure switch connector.
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 oil pressure switch and the ECM.■