Cummins ISX12 CM2250 (2010-12) Fault Code: 3313 PID: SPN: 4765 FMI: 4 Aftertreatment Diesel Oxidation Catalyst Intake Temperature Sensor Circuit- Voltage Below Normal, or Shorted to Low Source

Circuit Description
The aftertreatment temperature sensors are used by the electronic 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 this to a temperature value.

When the exhaust temperature is low, the sensor or 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 or low temperature. When the exhaust gas temperature is high, the sensor resistance is low. The signal voltage pulls down a large amount. Therefore, the ECM senses a low signal voltage, or a high temperature.

Component Location
The aftertreatment diesel oxidation catalyst intake temperature sensor is located in the aftertreatment system, between the outlet of the turbocharger and intake of the exhaust aftertreatment. Refer to the original equipment manufacturer (OEM) service manual.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position and when the engine is running.

Conditions for Setting the Fault Codes
The ECM detects that the aftertreatment diesel oxidation catalyst intake temperature sensor signal voltage is less than 0.1-VDC for more than 2 seconds.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp and/or Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
A default value for the aftertreatment diesel oxidation catalyst intake temperature sensor reading is used.
Diesel exhaust fluid injection into the aftertreatment system is disabled.
Active and stationary regeneration of the diesel particulate filter will be disabled.
The EGR valve will be closed.
Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.
Conditions for Clearing the Fault Code
To validate the repair, start the engine and let it idle for 1 minute.
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 Diagnostic (OBD) engines, the ECM will turn off the 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 faults, as well as extinguish the MIL for OBD applications.

Shop Talk
The aftertreatment diesel oxidation catalyst intake temperature sensor shares return wires in the OEM harness with other sensors. A shorted return wire can cause multiple fault codes to be active.

Possible causes of this fault include:

Signal shorted to ground in the harness
Signal shorted to return or ground in the sensor
Malfunctioning aftertreatment diesel particulate filter temperature sensor interface module.
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and datalink communication issues with Aftertreatment Components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing or intermittent connections.

Possible Cause:
1) Aftertreatment DPF temperature sensor interface module failure
2) Aftertreatment Interface module failure
3) OEM harness
4) ECM failure