The Cummins fault code 2638 troubleshooting document is a 4-page factory diagnostic reference for the Cummins ISM and ISX CM871 (2007-09) engine platform, covering catalyst efficiency out of calibration (SPN 380, FMI 13/13). This fault code is logged when the temperature increase across the catalyst during an aftertreatment injection event is lower than expected, indicating catalyst efficiency is out of calibration from an in-range failure. This page summarises what the manual contains so a technician can confirm it matches the code before downloading.
Official document details
| Brand | Cummins |
| Model coverage | ISM & ISX CM871 (2007-09) |
| System / group | ISM CM871 (2007-09) / DTCs |
| Circuit | ISX and ISM Aftertreatment System |
| Fault identifiers | SPN 380 · FMI 13/13 |
| Source | TruckFaultCodes.com (© 2017) |
| Pages | 4 |
| File size | 0.1 MB |
| Format | |
| Language | English |
Cummins fault code 2638 overview
This fault code is logged when the temperature increase across the catalyst during an aftertreatment injection event is lower than expected, indicating catalyst efficiency is out of calibration from an in-range failure. Three temperature sensors monitor the diesel oxidation catalyst and diesel particulate filter. Verify the ECM calibration is correct.
The document lists possible causes including:
- A temperature rise across the catalyst lower than expected during injection
- An in-range failure of the aftertreatment temperature sensors
- A degraded or contaminated diesel oxidation catalyst
Document table of contents
- Description
- Shop Talk
- Component Location
- Troubleshooting Steps
Applicable truck models covered
This procedure applies to Cummins ISM and ISX engines built on the CM871 (2007-09) electronic control platform, as fitted by truck makers using this Cummins driveline. The aftertreatment diesel oxidation catalyst is in the exhaust and monitored by three temperature sensors. For wiring, connector, and CPL detail, refer to the Cummins official engine support site or the OEM service manual.
Who needs this Cummins fault code 2638 manual
Fleet technicians and workshop owners diagnosing low catalyst efficiency on ISM or ISX CM871 engines use this reference to follow the factory step order instead of guessing at the diesel particulate filter circuit. The full PDF is available in the DiagTechPro manuals library, and a free account is required to download.
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
