Cummins fault code 427 is the Cummins ISM CM871 (2007-09) diagnostic reference for SAE J1939 Datalink – Abnormal Update Rate, reported as PID S231, SPN 639, FMI 9/9 with an None lamp. This 3-page workshop PDF covers the SAE J1939 Data Link Circuit (ISX and ISM), giving the fault description, shop-talk notes, component location and the step-by-step troubleshooting tree. It is compiled from the TruckFaultCodes.com fault-code library (Copyright © 2017).
Official document details — Cummins fault code
| Brand | Cummins |
| Model coverage | ISM and ISX CM871 (2007-09) engines |
| System / Group | SAE J1939 Data Link Circuit (ISX and ISM) / DTCs |
| Fault identifiers | PID S231, SPN 639, FMI 9/9, None lamp |
| Source | TruckFaultCodes.com fault-code library (© 2017) |
| Pages | 3 |
| File size | 0.08 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code header (PID, SPN, FMI, lamp)
- Description
- Shop Talk
- Component Location
- Troubleshooting Steps
Reading Cummins fault code 427
Devices such as ABS controllers, automated transmissions, ASR systems, electronic displays and vehicle electronic control units communicate with the ECM over the SAE J1939 data link; this code sets when the ECM stops receiving datalink commands it had been receiving from an external OEM device.
The Cummins Shop Talk section advises confirming the ECM calibration is correct and recalibrating if necessary. Documented possible causes include:
- grounded, shorted, or open circuits in the SAE J1939 data link wiring
- a device tying up communications by sending too many consecutive messages
- a failed external OEM controlling device that can no longer transmit
Component location manual information
The ECM sits on the intake side of the engine near the front; the SAE J1939 wiring and devices vary by OEM.
Applicable truck models
This document applies to Cummins ISM CM871 (2007-09) engines, and the same circuit description is shared with the ISX CM871 platform where noted in the extract. These engines power many Class 8 highway tractors and vocational trucks built by North American OEMs. Confirm the exact ECM calibration and OEM wiring against the manufacturer records; full engine support is published by Cummins official engine support.
Who needs this Cummins fault code 427 manual
Fleet technicians, independent diesel mechanics and workshop owners diagnosing an active SAE J1939 datalink condition will use this sheet to follow the correct troubleshooting order instead of replacing parts on guesswork.
The full PDF is available in the DiagTechPro manuals library; a free account is required to download it.
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