CM850 Electronic Control System – FAULT CODE 1681

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Overview

Circuit: Aftertreatment Control System SMALL | MEDIUM | LARGE

Circuit Description

The Dosing Control Unit communicates to the primary engine Electronic Control Module (ECM) through the J1939 datalink network. The dosing control unit precisely measures the amount of catalyst solution to be injected into the aftertreatment system. The dosing control unit has three primary cycles. A priming cycle at initial key on makes sure that catalyst solution is available at the dosing control unit. During the dosing cycle, catalyst solution is being delivered to the aftertreatment nozzle. A purge cycle occurs when the engine is turned off. The purge cycle makes sure that all the catalyst solution is removed from the aftertreatment line and nozzle.

Component Location

The Dosing Control Unit location is OEM dependent.

Shop Talk

Fault code 1681 is triggered when the Dosing Control Unit has detected an internal error. The only troubleshooting that can be done is to recalibrate the engine ECM. If fault code 1681 is still active after the engine ECM has been recalibrated, the Dosing Control Unit will need to be replaced.

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 MIL lamp and fault code can also be cleared using the INSITE™ 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 MIL lamp cannot be cleared using the INSITE™ service tool.
• The fault code will be cleared from memory after 400 days or 9600 hours of engine operation.

Refer to Troubleshooting Fault Code t05-1681