Cummins fault code 1943 is documented on this DiagTechPro library page for Cummins ISM CM871 (2007-09) engines, where it flags the Ambient Air Density – Data Valid but Below Normal Operational Range – Least Severe Level condition (SPN 3555, FMI 1/17). This 3-page PDF reproduces the manufacturer description, shop talk, component location and step-by-step troubleshooting so technicians can confirm and clear the code.
Cummins fault code 1943 overview
Cummins identifies this code as “Ambient Air Density – Data Valid but Below Normal Operational Range – Least Severe Level” on the Barometric Pressure Circuit. The ambient air pressure sensor responds to pressure changes in the atmospheric pressure. The pressure changes as the engine’s elevation changes. The ambient air pressure sensor has a 5-volt supply circuit, a sensor signal voltage, and a return circuit. The electronic control module (ECM) provides a 5-volt supply to the ambient air pressure sensor on the sensor supply 1 circuit. The ECM also provides a ground on the sensor return circuit. The ambient air pressure sensor provides a signal to the ECM on the ambient air pressure sensor signal circuit. This sensor signal voltage changes based on the pressure of the atmosphere. The ECM will detect a low signal voltage when the vehicle is operating at high altitudes. The ECM will detect a high signal voltage when the vehicle is operating at sea level altitudes.
Official document details
| Brand | Cummins |
| Model coverage | Cummins ISM CM871 (2007-09); Cummins ISX CM871 (2007-09) |
| System / Group | Barometric Pressure Circuit — ISM CM871 fault codes |
| Fault code | 1943 (SPN 3555, FMI 1/17) |
| Source | TruckFaultCodes.com Cummins fault code reference (© 2017) |
| Pages | 3 |
| File size | 0.1 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification (PID, SPN, FMI, lamp)
- Description
- Shop Talk
- Component Location
- Troubleshooting Steps
Applicable truck models and engines
This document applies to Cummins ISM CM871 (2007-09); Cummins ISX CM871 (2007-09) equipped diesel engines that log Fault Code 1943. Always confirm engine calibration and use a Cummins diagnostic tool such as INSITE to read live data before replacing parts. Full specifications are published on the Cummins official website.
Who needs this Cummins fault code 1943 manual
Heavy-duty truck technicians, fleet workshops and owner-operators diagnosing an electronic control module warning on ISM CM871 engines use this sheet to verify the fault before parts are replaced.
The full PDF is available in the DiagTechPro manuals library; 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
