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Komatsu 6251-81-9930 is the SAA6D125E-5 engine wiring harness in yellow braided sleeve and black conduit, with numbered branch tags, sealed sensor plugs and the main engine controller connectors. It is used on Komatsu PC400-8 and PC450-8 excavators. This aftermarket version has the same mounting and electrical connector as the original, so it plugs in and bolts on where the old one came off.
Sold as one unit. Check the number on your old part, or in the parts manual for your machine, before ordering.
| Part Type | Engine Wiring Harness |
| Replaces | Komatsu 6251-81-9930 |
| Machine | Komatsu PC400-8, PC450-8 excavators |
| Engine | Komatsu SAA6D125E-5 |
| Fits | Komatsu PC400-8 and PC450-8 excavators with the SAA6D125E-5 engine |
| Condition | New, aftermarket |
| Stat. HS-Code | 854430 |
| Country of Manufacture | China |
Komatsu machines
Check the part number on your old unit before ordering.
| Komatsu Part No.(SPM Part No.) | Fits |
|---|---|
| 6251-81-9930(SPM-HEP-5043) | Komatsu PC400-8 and PC450-8 excavators with the SAA6D125E-5 engine |
Intermittent faults and warning codes
Chafed, crushed or corroded wires in an engine or main harness give faults that come and go: sensor codes, a rough running engine or a machine that will not start. When several sensors fault at once, look at the harness.
Heat and rodent damage
Harnesses next to the exhaust and turbo go brittle and crack, and rodents chew the insulation on machines that stand. A new harness is quicker than repairing many wires.
Burnt or corroded plugs
Green corrosion or melted pins in the plugs cause high resistance and false readings. Replacing the harness renews every plug at once.
Fitting tips
Disconnect the batteries first, photograph or label every plug before removing the old harness, route the new one along the same clips and away from hot and moving parts, then clear the fault codes and test.
We check what other aftermarket sellers charge for this same part. Their prices on the date we checked:
| Seller | Price | Checked |
|---|---|---|
| SINOCMP | USD 499.00 | 2 Nov 2026 |
| eBay (4 aftermarket sellers) | USD 615.00 to 640.00 | 2 Nov 2026 |
| Spare Part Mart | USD 399.20 | Today |
Our price of USD 399.20 is 20% to 38% less than these sellers.
Found this part cheaper somewhere else? Send us the listing and we will beat it by 5% under our Price Beat Guarantee. Every order is also covered by our 30 day money back guarantee.
Yes, it was made for the Komatsu PC400-8, and 1 more listed under compatible equipment. Check the old wiring harness is marked 6251-81-9930 or one of the cross references, because makers change parts between serial ranges.
On the Komatsu PC400-8, there is no fixed interval. It is changed when it fails, and many fail from water in the plug or chafed wiring rather than wear.
A fault code for this circuit, readings that jump or stay fixed, or a part that does not respond with power at the plug.
A little dielectric grease keeps water out of the plug on machines that work outside. Make sure the terminals are clean and tight first.
Read the fault codes, then check the plug and wiring for corrosion or a broken wire. A wiring fault reads the same as a failed wiring harness.
No. It is an aftermarket wiring harness made to replace the Komatsu 6251-81-9930. It is not made by the original manufacturer; the number only shows what it replaces.
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