Cummins ISX12 CM2250 (2010-12) Fault Code: 3312 PID: SPN: 3246 FMI: 0 Aftertreatment Diesel Particulate Filter Outlet Temperature- Data Valid But Above Normal Operating Range- Most Severe Level

Circuit Description
The aftertreatment temperature sensors are used by the engine control module 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 engine control module provides a 5 volt reference voltage to the sensor. The engine control module monitors the change in signal voltage and converts this to a temperature value.

When the exhaust gas temperature is low, the sensor or thermistor resistance is high. The engine control module signal voltage only pulls down a small amount through the sensor to ground. Therefore, the engine control module 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 engine control module senses a low signal voltage, or a high temperature.

Component Location
The aftertreatment diesel particulate filter outlet temperature sensor is located in the aftertreatment system. It is located at the outlet of the aftertreatment diesel particulate filter. Refer to the original equipment manufacturer service manual.

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

Conditions for Setting the Fault Codes
The engine control module detects that the aftertreatment diesel particulate filter outlet temperature reading is greater than 800?C [1472?F] for 20 seconds.

Action Taken When the Fault Code is Active
The engine control module illuminates the red STOP ENGINE lamp immediately when the diagnostic runs and fails.
Active and stationary regeneration of the diesel particulate filter will be disabled.
The exhaust gas recirculation valve will be closed.
Engine shutdown if the engine protection shutdown feature is enabled.
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. This fault code will stay active until the next key cycle, even if the temperatures fall below the warning limits.
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The engine control module will turn off the red STOP ENGINE lamp after the diagnostic runs and passes.
The Reset All Faults command in INSITE? electronic service tool can be used to clear active and inactive faults.

Shop Talk
This fault will go inactive after the aftertreatment temperatures drop below the warning limit and a key cycle has occurred, and will likely be inactive when the vehicle is in the shop. For these reasons, this troubleshooting tree must be used for both active and inactive fault codes.

Possible causes of this fault code include:

A malfunctioning fuel injector caused unburned fuel to enter the exhaust system
Aftertreatment diesel particulate filter outlet temperature sensor failed in-range
Excessive engine oil being introduced into the exhaust system from the engine
Engine brake malfunctioned.
Reference the appropriate original equipment manufacturer wiring diagram when troubleshooting circuits that utilize wiring supplied by the original equipment manufacturer.

For intermittent power supply and datalink communication issues with aftertreatment components, it is highly recommended that the original equipment manufacturer power distribution center fuses and relays be thoroughly checked for loose, missing, or intermittent connections.

Possible Cause:
1) ECM calibration