CM850 Electronic Control System – FAULT CODE 1677

Catalyst Tank Temperature — Voltage Below Normal, or Shorted to Low Source


Overview

CODE REASON EFFECT
Fault Code: 1677
PID: 
SPN: 3031
FMI: 4
LAMP: Amber
SRT: 

Catalyst Tank Temperature — Voltage Below Normal, or Shorted to Low Source. Low signal voltage detected at the catalyst solution temperature sensor circuit.

Default temperature used for catalyst solution temperature.

Circuit: Catalyst Solution Temperature Sensor
SMALL | MEDIUM | LARGE

Circuit Description

The catalyst solution temperature sensor is used by the electronic control module (ECM) to monitor the temperature of the catalyst solution inside the catalyst tank. The ECM monitors the voltage on the signal pin and converts this to a temperature value.

Component Location

The catalyst solution temperature sensor is located in the catalyst tank. The tank is mounted by the OEM. For more information, contact the OEM service manual.

Shop Talk

The catalyst solution temperature sensor shares return wires in the engine harness with other sensors. A shorted return can cause multiple fault codes to be active. Before troubleshooting Fault Code 1677, check for multiple fault codes.

Possible causes of this fault code include:

  • Signal shorted to ground in the harness
  • Signal shorted to return or ground in the sensor.

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 t05-1677

Last Modified:  08-Jul-2010