CM850 Electronic Control System – FAULT CODE 1689

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Overview

Real-Time Clock Power Circuit SMALL | MEDIUM | LARGE

Circuit Description

Under ordinary operating conditions, the real-time clock in the electronic control module (ECM) is powered by the vehicle’s batteries. If battery power to the ECM is lost, then the real-time clock will be powered by a battery in the engine harness (if equipped).

Component Location

The real-time clock battery is secured to the engine harness near the ECM. Refer to Procedure 100-002 (Engine Diagrams) in Section E for a detailed component location view.

Shop Talk

This fault indicates that the real-time clock in the ECM lost power. Possible causes for this fault are weak or failed real-time clock battery, failed wiring or connectors between the battery and ECM, or the engine is not equipped with a real-time clock battery and the vehicle battery power to the ECM is lost.

NOTE:If the Real Time Clock is supplied by the OEM via a CAN BUS and a battery backup is not used, then refer to the OEM wiring diagram. If this is the case, then` check INSITE™ electronic service tool, “Advanced ECM Data – Real Time Clock Settings.” If the OEM supplies a Real Time Clock signal, then the address must be set according to the OEM wiring or the fault code will become active.

On-Board Diagnostics (OBD) Information (Euro 4 Certified Engines):

• The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
• The ECM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. The malfunction indicator lamp and fault code can also be cleared using the INSITE™ electronic service tool.
• The fault code will be cleared from memory after 40 consecutive drive cycles where the diagnostic runs and passes.

On-Board Diagnostics (OBD) Information (Euro 4 Stage 1+ Certified Engines):

• The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
• An engine torque derate will be activated after 50 hours of engine operation with the fault code active.
• The ECM turns OFF the malfunction indicator lamp (MIL) after 1 ignition cycle that the diagnostic runs and does not fail. The malfunction indicator lamp and fault code can also be cleared using the INSITE™ electronic service tool.
• The fault code will be cleared from memory after 400 days or 9600 hours of engine operation.

Refer to Troubleshooting Fault Code t05-1689