CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – FAULT CODE 1696

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Overview

ISX and ISM – Sensor Supply 5 SMALL | MEDIUM | LARGE

Circuit Description

The sensor supply 5 of the electronic control module (ECM) provides a 5 volt supply for the aftertreatment diesel particulate filter differential pressure sensor, remote accelerator, tachograph speed sensor, and accelerator position sensor 2. The remote accelerator and tachograph speed sensor are optional original equipment manufacturer (OEM) components.

Component Location

Sensor supply number 5 is located in the ECM OEM harness connector and provides a 5 volt supply to various components in the OEM harness.

Conditions for Running the Diagnostics

This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes

The ECM detects that the sensor supply 5 signal voltage is less than 4.75-VDC for more than 1 second.

Action Taken When the Fault Code is Active

• The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
• A default value for the aftertreatment diesel particulate filter differential pressure is used.
• Active regeneration of the aftertreatment diesel particulate filter will be disabled.
• The engine has limp home throttle control only.

Conditions for Clearing the Fault Code

The ECM will turn off the amber CHECK ENGINE light immediately after the diagnostic runs and passes.

Shop Talk

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM. Refer to Procedure 019-032 (ECM Calibration Code) in Section 19 in the corresponding Troubleshooting and Repair Manual for the engine being serviced.

Low voltage on the 5 volt supply wire can be caused by a short circuit to ground in a supply wire, a short circuit between a supply wire and a return wire, a failed sensor, or a failed ECM power supply.

Refer to Troubleshooting Fault Code t05-1696