This guide explains how to troubleshoot and repair Caterpillar fault code 24, PID 100-3 (Oil Pressure Voltage High).
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Fault Detection Conditions
The Engine Control Module (ECM) will log this code when:
- Oil pressure sensor signal voltage exceeds 4.95 VDC for more than 8 seconds.
- The ECM has been powered for at least 2 seconds.
- 168-01 Low ECM Battery Power is not active.
- 232-03 5 Volt Supply Voltage High is not active.
- 232-04 5 Volt Supply Voltage Low is not active.
- The engine is not running or the coolant temperature is above 38°C (100°F).
How the ECM Detects the Fault
The ECM sends a constant pull-up voltage to the sensor’s signal wire. This allows it to check for wiring or circuit problems:
- If the signal voltage is too high, a -3 code is activated.
- If the signal voltage is too low, a -4 code is activated.
Note: Caterpillar Electronic Technician (ET) may take up to 30 seconds to display an active diagnostic code. Always wait before confirming code status.
Most Likely Cause
- Faulty wiring or poor electrical connection.
Least Likely Cause
- ECM failure.
Probable Causes & Checks
- ECM Connection – Inspect for loose, corroded, or damaged pins.
- Sensor or Harness Failure – Test the oil pressure sensor and wiring harness for continuity, shorts, or open circuits.
- Failed ECM – Consider only after all wiring and sensor checks pass.
More repair case for Caterpillar machine,please refer to:Caterpillar Machine Repair
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