SPN 3241 - FMI 2 (Fault Code 1667)
SPN3241 FMI2
Aftertreatment Exhaust Gas Temperature 1 - Data Erratic, Intermittent, or Incorrect
CODES:
Fault Code: 1667
PID(P), SID(S): None
SPN: 3241
FMI: 2/2
Lamp: Amber
REASON: Aftertreatment Exhaust Gas Temperature 1 - Data Erratic, Intermittent, or Incorrect. The
aftertreatment diesel oxidation catalyst inlet temperature sensor is not changing with engine operating conditions.
EFFECT: Active aftertreatment diesel particulate filter regeneration will be disabled.
Circuit Description:
The aftertreatment temperature sensors are used by the engine control module (ECM) to monitor the engine exhaust temperatures in the aftertreatment system. The aftertreatment temperature sensors are thermistors and change resistance based on the temperature being measured. The ECM provides a 5 volt reference voltage to the sensor. The ECM monitors the change in signal voltage and converts it to a temperature value. When the exhaust temperature is low, the thermistor resistance is high. The ECM signal voltage only pulls down a small amount through the sensor to ground. Therefore, the ECM senses a high signal voltage (low temperature). When the exhaust gas temperature is high, the thermistor resistance is low. The signal voltage pulls down a large amount. Therefore, the ECM senses a low signal voltage (high temperature).
Component Location:
The aftertreatment diesel oxidation catalyst inlet temperature sensor is located in the aftertreatment system. It is located at the inlet of the diesel oxidation catalyst. See equipment manufacturer service information.
Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine is running and fuel injection into the aftertreatment system is not occurring.
Conditions for Setting the Fault Codes:
The ECM detects that the aftertreatment diesel oxidation catalyst inlet temperature sensor reading is not changing with engine operating conditions.
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 oxidation catalyst inlet temperature reading is used.
• Active regeneration of the aftertreatment diesel particulate filter is disabled.
Conditions for Clearing the Fault Code:
• To validate the repair using a Diagnostic Road Test, utilize a route that incorporates both stop-and-go city driving and steady-state highway driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.
• To validate the repair using a Chassis Dynamometer Test, utilize a routine that incorporates acceleration and motoring events, steady-state highway operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.
• The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
• The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
• For On-Board Diagnostics (OBD) engines, the ECM will turn off the malfunction indicator lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
• The "Reset All Faults" command in INSITE™ electronic service tool can be used to clear active and inactive fault codes, as well as extinguish the MIL for OBD applications.
Shop Talk:
Verify the ECM calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM.
The aftertreatment sensors share a common ground wire with the coolant level sensor. Fault codes or problems related to the coolant level sensor and its ground circuit could potentially cause this fault.
Possible causes of this fault code include:
• Coolant level sensor and/or coolant level sensor ground circuit fault codes or related problems
• Stuck in-range aftertreatment diesel oxidation catalyst inlet temperature sensor
• High resistance in the aftertreatment diesel oxidation catalyst inlet temperature sensor SIGNAL or RETURN wires.
• Miswired OEM harness
• Face plugged or damaged aftertreatment diesel oxidation catalyst.
Read More:
SPN 3241 - FMI 4 (Fault Code 1665)
SPN 3241 - FMI 3 (Fault Code 1666)
Blog.Teknisi
Aftertreatment Exhaust Gas Temperature 1 - Data Erratic, Intermittent, or Incorrect
 |
| Aftertreatment Temperature Sensors |
CODES:
Fault Code: 1667
PID(P), SID(S): None
SPN: 3241
FMI: 2/2
Lamp: Amber
REASON: Aftertreatment Exhaust Gas Temperature 1 - Data Erratic, Intermittent, or Incorrect. The
aftertreatment diesel oxidation catalyst inlet temperature sensor is not changing with engine operating conditions.
EFFECT: Active aftertreatment diesel particulate filter regeneration will be disabled.
Circuit Description:
The aftertreatment temperature sensors are used by the engine control module (ECM) to monitor the engine exhaust temperatures in the aftertreatment system. The aftertreatment temperature sensors are thermistors and change resistance based on the temperature being measured. The ECM provides a 5 volt reference voltage to the sensor. The ECM monitors the change in signal voltage and converts it to a temperature value. When the exhaust temperature is low, the thermistor resistance is high. The ECM signal voltage only pulls down a small amount through the sensor to ground. Therefore, the ECM senses a high signal voltage (low temperature). When the exhaust gas temperature is high, the thermistor resistance is low. The signal voltage pulls down a large amount. Therefore, the ECM senses a low signal voltage (high temperature).
Component Location:
The aftertreatment diesel oxidation catalyst inlet temperature sensor is located in the aftertreatment system. It is located at the inlet of the diesel oxidation catalyst. See equipment manufacturer service information.
Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine is running and fuel injection into the aftertreatment system is not occurring.
Conditions for Setting the Fault Codes:
The ECM detects that the aftertreatment diesel oxidation catalyst inlet temperature sensor reading is not changing with engine operating conditions.
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 oxidation catalyst inlet temperature reading is used.
• Active regeneration of the aftertreatment diesel particulate filter is disabled.
Conditions for Clearing the Fault Code:
• To validate the repair using a Diagnostic Road Test, utilize a route that incorporates both stop-and-go city driving and steady-state highway driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.
• To validate the repair using a Chassis Dynamometer Test, utilize a routine that incorporates acceleration and motoring events, steady-state highway operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.
• The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
• The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
• For On-Board Diagnostics (OBD) engines, the ECM will turn off the malfunction indicator lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
• The "Reset All Faults" command in INSITE™ electronic service tool can be used to clear active and inactive fault codes, as well as extinguish the MIL for OBD applications.
Shop Talk:
Verify the ECM calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM.
The aftertreatment sensors share a common ground wire with the coolant level sensor. Fault codes or problems related to the coolant level sensor and its ground circuit could potentially cause this fault.
Possible causes of this fault code include:
• Coolant level sensor and/or coolant level sensor ground circuit fault codes or related problems
• Stuck in-range aftertreatment diesel oxidation catalyst inlet temperature sensor
• High resistance in the aftertreatment diesel oxidation catalyst inlet temperature sensor SIGNAL or RETURN wires.
• Miswired OEM harness
• Face plugged or damaged aftertreatment diesel oxidation catalyst.
Read More:
SPN 3241 - FMI 4 (Fault Code 1665)
SPN 3241 - FMI 3 (Fault Code 1666)
Blog.Teknisi
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