SPN 558 FMI 4 is a Detroit fault code reference sheet that documents the a short to ground or an open wire on the idle validation switch circuit diagnostic for DD Series engines built to EPA 2007 and later emissions standards. This single-topic page reproduces the factory-style test order Detroit dealers and independent shops follow for the Idle Validation Switch (IVS) circuit, from confirming related codes through to the final repair decision.
Official document details
| Brand | Detroit |
| Model coverage | DD Series (EPA 2007-Current) |
| System / group | Diagnostic Trouble Codes (DTCs) |
| Suspect Parameter Number | 558 |
| Failure Mode Identifier | 4 |
| Emissions revision | all model years |
| Source | Detroit fault code sheet (© 2017, www.TruckFaultCodes.com) |
| Pages | 2 |
| File size | 0.27 MB |
| Format | |
| Language | English |
SPN 558 FMI 4 troubleshooting steps
The sheet lists the ordered checks Detroit publishes for this code, so a technician can rule out network and power-supply faults before condemning a switch, sensor or module. The main steps are:
- Disconnect the Idle Validation Switch (IVS) and the Common Powertrain Controller (CPC) #1 connector.
- Measure the resistance between pin 4 of the IVS connector and ground; if it reads low, repair the short to ground between CPC #1 pin 6 and IVS pin 4.
- Otherwise measure the resistance between pin 5 of the IVS connector and ground; if low, repair the short between CPC #1 pin 3 and IVS pin 5.
- If neither reads low, replace the IVS following the Original Equipment Manufacturer (OEM) procedures.
Applicable truck models
This code applies to Detroit DD Series diesel engines (EPA 2007 to current) and, for the shared driveline codes, to Series 60 (DDEC VI) installations that use the same Common Powertrain Controller and Motor Control Module architecture. Coverage is defined by the engine and control-module configuration rather than the truck badge, so confirm the exact build against the current model line on the Detroit Diesel official website.
Who needs this SPN 558 FMI 4 manual
This SPN 558 FMI 4 manual is written for diesel technicians and DD Series fleet owners who are isolating a short to ground or open wire on the idle validation switch and want the exact Detroit test order before ordering parts. Following the documented sequence keeps unnecessary sensor and module replacements to a minimum.
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