SPN 168 FMI 14 is the Detroit DD Series diagnostic trouble code for ecu power down not completed (main battery terminal possibly floating), and this page documents its official engine charging and battery power circuit troubleshooting sheet. The sheet also covers the related Opt Idle charging-system or battery-failure condition and reminds the technician to inspect any battery disconnect switch for proper connections.
SPN 168 FMI 14 document details
| Brand | Detroit |
| Model coverage | DD Series — DD13, DD15, DD16 |
| System / group | DD Series (EPA 2007-Current) / DTCs |
| SPN | 168 |
| FMI | 14 |
| Fault | ECU Power Down Not Completed (Main Battery Terminal Possibly Floating) |
| Emissions / revision | All years — Copyright 2017 |
| Pages | 2 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Fault description and battery disconnect switch note
- Alternator drive belt inspection
- Alternator mounting and operation check
- Battery charge-holding test
- Battery voltage to CPC #2 connector pin 1
Troubleshooting steps summarised
Troubleshooting starts at the alternator: the drive belt condition is checked and replaced if required, then the alternator mounting is re-tightened and alternator operation is verified. If the fault stays active the battery is load-checked, and finally the sheet directs a check for loss of battery voltage to pin 1 of the Common Powertrain Controller (CPC) #2 connector, referring to Original Equipment Manufacturer (OEM) power-distribution schematics to restore it.
Applicable truck models covered
The document applies across all model years of the Detroit DD Series (DD13, DD15 and DD16) that use the Common Powertrain Controller charging monitor. For engine specifications and warranty coverage, refer to the official Demand Detroit service resources. These troubleshooting steps are cross-checked with the Detroit Diesel Diagnostic Link (DDDL) and the official Demand Detroit service resources.
Who needs this SPN 168 FMI 14 guide
Technicians chasing a floating main battery terminal, an intermittent power-down complaint, or a charging-system fault after an Opt Idle event rely on this sheet to separate belt, alternator, battery and wiring causes.
The full PDF is available in the DiagTechPro manuals library; a free account is required to download the complete step-by-step document.
Related manuals library
