SPN 3242 FMI 2 is the Detroit DD Series fault-code procedure for a diesel oxidation catalyst inlet temperature plausibility error. This 8-page diagnostic PDF documents the fault, its monitored circuit on the diesel oxidation catalyst (DOC) inlet temperature 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) | 3242 |
| FMI (failure mode) | 2 |
| Emission family | EPA07 calibration |
| Source | Detroit Power Service Literature (Copyright © 2017) |
| Pages | 8 |
| File size | 0.40 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification (SPN 3242, failure mode 2)
- Troubleshooting steps
- Temperature comparison and harness wiggle test
- Aftertreatment device contamination inspection
- DPF replacement and parked regeneration
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 EPA07 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 3242 FMI 2 manual
Diesel technicians, fleet workshops and mobile mechanics diagnosing a DOC inlet temperature plausibility error on EPA07 Detroit engines need this reference to test the circuit correctly with a diesel diagnostic tool instead of replacing parts by guesswork.
SPN 3242 FMI 2 repair steps explained
This eight-page plausibility procedure compares DOC inlet, DOC outlet and Diesel Particulate Filter (DPF) outlet temperatures, which should stay within 25 C of each other, and wiggle-tests the harness from the Aftertreatment Device (ATD) to the Motor Control Module (MCM). It then guides removal of the ATD to inspect the substrate for coolant or oil contamination, soot loading and fuel washout, with checks of the DPF inlet and outlet pressure sensors (0.44-0.56 volt), intake and exhaust leak tests, a turbocharger hysteresis test, and fuel-system pressure. The DPF is replaced and a parked regeneration is performed per Detroit Power Service Literature.
The full PDF is available in the DiagTechPro manuals library; a free account is required to download it.
Related manuals library
