This fault code 1678 DTCs document is a troubleshooting procedure for the aftertreatment diesel exhaust fluid tank temperature sensor circuit. It explains the voltage-above-normal or short-to-high-source fault, the ECM response, and guided diagnostic checks using INSITE™ electronic service tool.
Official fault code 1678 DTCs document details
| Brand | Cummins |
|---|---|
| Model coverage | ISB6.7 CM2250, with referenced coverage for ISX11.9 CM2250, ISC8.3 and ISL9 CM2250, and ISX15 CM2250 |
| System/Group | Aftertreatment Diesel Exhaust Fluid Tank Temperature Sensor Circuit / DTCs |
| Publication no. | Not shown for this PDF; associated bulletin number 4022254 is listed for ISB6.7 CM2250 procedures |
| Year/Revision | Unknown; pages show Last Modified: 21-Dec-2010 and 11-Jun-2010 |
| Pages | 11 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Overview
- Circuit Description
- Component Location
- Conditions for Running the Diagnostics
- Conditions for Setting the Fault Codes
- Action Taken When the Fault Code is Active
- Conditions for Clearing the Fault Code
- Shop Talk
- Associated Procedures
- Troubleshooting Steps
- Guided Step 1 – Check the fault codes
- Guided Step 2 – Check the aftertreatment diesel exhaust fluid tank temperature sensor and circuit
- Guided Step 3 – Check the aftertreatment diesel exhaust fluid controller and harness
- Guided Step 4 – Check ECM calibration and clear fault codes
Applicable truck models
This file applies to Cummins CM2250 engine platforms named in the extract: ISB6.7 CM2250, ISX11.9 CM2250, ISC8.3 and ISL9 CM2250, and ISX15 CM2250. The document states that diesel exhaust fluid tank and temperature sensor location is OEM dependent, so vehicle-specific tank location and sensor access must be checked in the OEM service manual. The fault concerns SPN 3031 FMI 3/3, where the diesel exhaust fluid controller detects diesel exhaust fluid tank temperature signal voltage above 4.7-VDC for more than 1 second. For official manufacturer information, visit Cummins.
Who needs this fault code 1678 DTCs manual
Workshop owners, diesel mechanics, and diagnostic technicians need this fault code 1678 DTCs manual when an amber CHECK ENGINE light or MIL is active for the DEF tank temperature sensor signal circuit. It is useful for checking connector damage, open return circuits, open signal circuits, shorts to voltage, controller harness response, and ECM calibration status.
The procedure uses INSITE™ electronic service tool to read fault codes, confirm inactive or active status, check circuit response after 30 seconds, and verify whether Fault Code 1677 becomes active while Fault Code 1678 becomes inactive during jumper-wire testing. Repair paths include cleaning or repairing connector pins, replacing the aftertreatment diesel exhaust fluid tank temperature sensor, repairing or replacing the aftertreatment diesel exhaust fluid controller harness, replacing the controller, or updating ECM calibration when applicable.
The full PDF is available in the DiagTechPro manuals library, free account 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
