SPN 3871 FMI 2 is the Detroit DD Series fault code sheet for the Transmission Speed Sensor (TSS) circuit, which is reported as a transmission speed failure. This two-page troubleshooting document, published on TruckFaultCodes.com, guides a technician from checking the Common Powertrain Controller (CPC4) configuration through resistance measurements at the CPC4 harness connectors. Use it to confirm whether the TSS is hardwired or transmitted over J1939 before making a repair.
Official document details
| Brand | Detroit |
|---|---|
| Model coverage | DD Series (EPA 2007-Current) and Series 60 (DDEC VI, EPA 2007) |
| System / Group | DTCs — Transmission Speed Sensor circuit |
| Fault code | SPN 3871, FMI 2 |
| Year / Revision | Copyright 2017 |
| Pages | 2 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code header — Transmission Speed Sensor circuit
- CPC4 reprogramming and TSS parameter check
- Hardwired versus J1939 decision step
- TSS harness connector inspection for bent or corroded pins
- Resistance measurements at CPC4 connector #3 and #4
- OEM literature reference for TSS sensor diagnostics
Applicable truck models for SPN 3871 FMI 2
The procedure covers trucks running the Detroit DD Series (EPA 2007 to current) and the Series 60 with DDEC VI. The TSS can be either hardwired to the CPC4 or transmitted over J1939, and the sheet points to the Application and Installation manual for the correct parameter configuration in each case. For J1939 vehicles it defers to the Original Equipment Manufacturer material; see the official Detroit powertrain site for engine and controller references.
Who needs this SPN 3871 FMI 2 manual
Fleet technicians and workshop owners diagnosing a 3871 FMI 2 alarm use this sheet to confirm the TSS parameters after any CPC4 reprogramming, inspect the harness connector, and measure resistance at CPC4 connectors #3 and #4 against battery ground. It keeps the repair tied to the documented steps rather than guesswork.
The complete PDF is available in the DiagTechPro manuals library; a free account is required to download it.
Related manuals library
Sản phẩm liên quan cho hãng này
Cùng brand theo taxonomy hiện có trong catalog WooCommerce.
Detroit Diesel Reports 6.3
Detroit Reprogramming Station (DDRS) 7.11
DDDL Backdoor Password: A Comprehensive Guide
