SPN 3226 FMI 13 is the Detroit DD Series fault-code procedure for an SCR outlet NOx sensor signal not available. This 5-page diagnostic PDF documents the fault, its monitored circuit on the SCR outlet NOx sensor, and the exact troubleshooting steps a technician follows to confirm and repair the failure.
Official document details
| Brand | Detroit |
| Model coverage | DD Series (EPA 2007-Current); Series 60 DDEC VI |
| System / Group | DD Series / DTCs |
| SPN (fault code) | 3226 |
| FMI (failure mode) | 13 |
| Emission family | EPA10 / GHG14 calibration |
| Source | Detroit Power Service Literature (Copyright © 2017) |
| Pages | 5 |
| File size | 0.37 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification (SPN 3226, failure mode 13)
- Fault description and enabling conditions
- Troubleshooting steps
- Sensor voltage and resistance checks
- ACM 120-pin connector tests
Applicable truck models
This procedure applies to Detroit DD13, DD15 and DD16 engines in the DD Series (EPA 2007-Current) range and the equivalent Series 60 (DDEC VI) platform, as fitted to Freightliner and Western Star trucks. Confirm the EPA10 / GHG14 emission family matches the truck before following the steps; full model and coverage data is published on the Detroit official website.
Who needs this SPN 3226 FMI 13 manual
Diesel technicians, fleet workshops and mobile mechanics diagnosing an SCR outlet NOx sensor with no signal on EPA10 or GHG14 Detroit engines need this reference to test the circuit correctly with a diesel diagnostic tool instead of replacing parts by guesswork.
SPN 3226 FMI 13 repair steps explained
After checking the DTC occurrence counter, the technician disconnects the SCR outlet NOx sensor, inspects the harness, and measures voltage between pins 1 and 4 (should be at least 11.5 volts) to isolate supply-side wiring to pins 42 and 43 of the Aftertreatment Control Module (ACM) 120-pin connector. Resistance between pins 2 and 3 should read 50 to 70 ohms; shorts, opens and greater-than-5-ohm wiring faults to pins 40 and 41 are then checked. The internal ACM resistor is verified last, and the sensor or the ACM is replaced per Detroit Power Service Literature.
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