Cummins fault code 321 is the Cummins ISM CM871 (2007-09) diagnostic reference for Injector Solenoid Driver Cylinder 4 Circuit – Current Above Normal, or Grounded Circuit, reported as PID S004, SPN 654, FMI 6/6 with an Amber lamp. This 6-page workshop PDF covers the Injector Solenoid Driver Cylinder 4 Circuit (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 | Injector Solenoid Driver Cylinder 4 Circuit (ISM) / DTCs |
| Fault identifiers | PID S004, SPN 654, FMI 6/6, Amber lamp |
| Source | TruckFaultCodes.com fault-code library (© 2017) |
| Pages | 6 |
| File size | 0.29 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 321
The injector solenoid valves are actuated by the ECM to control fuel metering and timing; each solenoid connects to the ECM by a supply and a return wire, is normally open, and closes only on an electrical pulse from the ECM during fuel injection and metering.
The Cummins Shop Talk section advises confirming the ECM calibration is correct and recalibrating if necessary. Documented possible causes include:
- an open circuit in the engine harness, connectors, or actuator
- a short circuit to a voltage source in the engine harness
- a short circuit between the injector positive and negative in the harness
- low or high resistance in the injector
Component location manual information
The ISM internal actuator harness connects to the external engine harness through a 15-pin connector at the front of the rocker lever housing and runs inside it with six connectors, one per injector solenoid.
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 321 manual
Fleet technicians, independent diesel mechanics and workshop owners diagnosing an active injector solenoid cylinder 4 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.
Related manuals library
Sản phẩm liên quan cho hãng này
Cùng brand theo taxonomy hiện có trong catalog WooCommerce.
Cummins Calterm Version 5.16 – Advanced ECM Control and Precision Tuning for Cummins Engines
Cummins INSITE 9.3 – The Essential Diagnostic Tool for Cummins Engines
Cummins InCal CE – The Calibration and Configuration Tool for Cummins Engines
