SPN 111 FMI 18 is a Detroit™ coolant-level diagnostic fault code, and this 2-page Detroit DD Series PDF documents the “Coolant Level Low” condition in full. This sheet covers a low engine coolant level report on GHG14 engines. After ruling out other codes and checking the reservoir, the procedure walks a coolant-leak inspection of the cylinder head gasket, air compressor head gasket, hoses, oil and radiator cap. The summary below sets out the official causes, tools and troubleshooting order so a technician can verify the code before downloading the complete manual.
Official document details
| Brand | Detroit |
| Model coverage | DD Series (EPA 2007-Current) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Publication no. | Not printed on sheet (Detroit™ via TruckFaultCodes.com, © 2017) |
| Year / Revision | 2017 |
| Pages | 2 |
| File size | 0.3 MB |
| Format | |
| Language | English |
SPN 111 FMI 18 document contents
- Fault code identification (SPN and FMI)
- Multiple-code check
- Coolant reservoir level check
- Engine coolant level sensor replacement
- Coolant-leak inspection checklist
Applicable truck models
The procedure applies to Detroit DD Series diesel engines on the GHG14 emissions platform. It requires the diagnostic tool and a systematic visual leak inspection. For factory service data, wiring diagrams and bulletins beyond this fault-code sheet, consult the official Detroit Diesel support site.
Who needs this SPN 111 FMI 18 manual
Technicians diagnosing recurring low coolant on a Detroit engine need this sheet to move from the sensor to the actual leak sources. It is useful for confirming a head-gasket or hose loss before major repair.
The routine has you repair other codes first, check the reservoir and, if it is within limits, replace the coolant level sensor, then inspect the head gasket, air compressor head gasket, hose connections, oil and radiator cap for leaks.
The full 2-page PDF is available in the DiagTechPro manuals library; a free account is required to download it. Every document in the library is indexed by suspect parameter number and failure mode identifier, so you can cross-reference related Detroit DD Series fault codes without leaving the page.
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