Introduction

Many senior Kobelco excavator owners and operators eventually encounter a frustrating dashboard warning after long hours of operation: the "Engine Oil Pressure Low" alarm pops up, followed by engine shutdown, power retention failure, and cranking failure. In this comprehensive troubleshooting guide, today, I’d like to share a quick, one-minute troubleshooting process that can accurately pinpoint and resolve this specific issue.

Engine Oil Pressure Low

Common Symptoms

• Dashboard warning: Engine Oil Pressure Low icon activated. 

• Sudden engine shutdown during operation.

• Electrical system remains energized / inability to cut power properly. 

• Starter motor fails to ignite / engine refuses to crank.

Step-by-Step Diagnostic & Repair Guide 

Step 1: Inspect the Alternator & Wiring 

First, inspect the alternator located in the engine compartment. The alternator has a plug connector with two wires: a white wire and a yellow-red wire. Cut or disconnect the yellow-red wire, extend a temporary jumper wire from it, and ground it directly onto the iron body/plate. If the excavator returns to normal operation, starts successfully, and shuts down properly, it indicates that the alternator itself is faulty and needs repair or replacement.

Step 2: Check the Fuse Box & Relays

If the warning alarm persists after checking the alternator, proceed to the fuse box. Locate the alternator relay inside the fuse box and pull it out. Check if the system recovers. If pulling the relay restores normal function, the relay or its intermediate wiring is problematic. If pulling it does not work, try swapping identical relays. If the issue still persists, the fuse box or its underlying wiring harness requires deeper inspection.

The generator relay inside the fuse box

Step 3: Inspect the 100A Main Fuse

Another hidden culprit is located inside the battery/relay protective enclosure. There is a heavy-duty 100-ampere main fuse. If this main fuse is blown or burnt out, it will also trigger this exact low oil pressure alarm and electrical fault code.

100-amp fuse