SPN 164 FMI 1 is a Detroit™ fuel-metering diagnostic fault code, and this 3-page Detroit DD Series PDF documents the “Quantity Control Valve Low Side Driver Error” condition in full. The monitored parameter is the Quantity Control Valve, and the code sets in about two seconds whenever enabling conditions are met, lighting the MIL and CEL and forcing a 25 percent engine derate. It can occur when the MCM pin 2 circuit is shorted to power or when the quantity control valve has an internal short. 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 | 3 |
| File size | 0.3 MB |
| Format | |
| Language | English |
SPN 164 FMI 1 document contents
- Fault code identification (SPN and FMI)
- Monitored parameter and engine reaction
- Possible causes
- QCV harness connector inspection
- Resistance measurement across pins 1 and 2
- MCM 120-pin connector checks and replacement
Applicable truck models
This applies to Detroit DD Series diesel engines across all model years, covering both three-filter and two-filter fuel systems. Diagnosis uses a digital volt-ohm meter and the Motor Control Module 120-pin connector. For factory service data, wiring diagrams and bulletins beyond this fault-code sheet, consult the official Detroit Diesel support site.
Who needs this SPN 164 FMI 1 manual
Fuel-system technicians facing a 25 percent derate with MIL and CEL lamps need this sheet to distinguish a shorted valve from a wiring or MCM fault before ordering parts. It is also useful for shops verifying QCV resistance specifications.
The routine has you inspect the QCV connector, measure resistance across pins 1 and 2 (expected between 1.0 and 2.0 ohms), then check the MCM 120-pin connector and either repair the short circuit or replace the QCV or Motor Control Module.
The full 3-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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