Cummins ISX11.9 CM2250 – Service Manual 019-464   Aftertreatment SCR Catalyst Temperature Sensor Interface Module

The aftertreatment selective catalytic reduction (SCR) catalyst temperature sensor interface module is used to connect the original equipment manufacturer (OEM) wiring harness to the aftertreatment SCR catalyst intake temperature sensor and aftertreatment SCR catalyst outlet temperature sensor.

The aftertreatment SCR catalyst temperature sensor interface module is located on the aftertreatment SCR catalyst.  It is mounted to the aftertreatment SCR catalyst temperature sensor interface module mounting bracket.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Disconnect the vehicle batteries. Refer to the OEM service manual.
• Squeeze the locking tabs and pull the connectors apart to disconnect the OEM wiring harness connector, the aftertreatment SCR catalyst intake temperature sensor connector, and the aftertreatment SCR catalyst outlet temperature sensor connector.

Remove the two capscrews holding the aftertreatment SCR catalyst temperature sensor interface module to the aftertreatment SCR catalyst temperature sensor interface module mounting bracket.

Inspect the aftertreatment SCR catalyst temperature sensor interface module connectors for dirty or damaged pins. Use the following procedure for general inspection techniques. Refer to Procedure 019-361 in Section 19.

The aftertreatment SCR catalyst temperature sensor interface module acts as an interface to the OEM wiring harness.

The resistance of each circuit must be checked to detect any circuit malfunctions.

Use the following procedure for general resistance measurement techniques. Refer to Procedure 019-360 in Section 19.

The SCR catalyst intake temperature sensor and the SCR catalyst outlet temperature sensor share a common return.

Check the continuity between the SCR catalyst intake temperature sensor return, the SCR catalyst outlet temperature sensor return, and the temperature return pin of the aftertreatment SCR catalyst temperature sensor interface module. If the resistance is greater than 10 ohms for any circuit, the aftertreatment SCR catalyst temperature sensor interface module must be replaced.

Refer to the wiring diagram for connector pin identification.

Each temperature sensor has a dedicated signal circuit within the aftertreatment SCR catalyst temperature sensor interface module.

Check the continuity of each temperature sensor signal circuit in the aftertreatment SCR catalyst temperature sensor interface module. If the resistance is greater than 10 ohms for any circuit, the aftertreatment SCR catalyst temperature sensor interface module must be replaced.

Refer to the wiring diagram for connector pin identification.

Each circuit within the aftertreatment SCR catalyst interface module must be checked for short circuits.

Use the following procedure for general resistance measurement techniques. Refer to Procedure 019-360 in Section 19.

The aftertreatment SCR catalyst temperature sensor interface module RETURN circuit must not be shorted to any of the SIGNAL circuits.

Measure the resistance between the temperature RETURN and each of the temperature sensor SIGNAL circuits. If a short circuit has been detected (less than 100k ohms), the aftertreatment SCR catalyst temperature sensor interface module must be replaced.

Refer to the wiring diagram for connector pin identification.

Each temperature sensor has a dedicated SIGNAL circuit within the aftertreatment SCR catalyst temperature sensor interface module.

Measure the resistance between the SCR catalyst intake temperature sensor SIGNAL circuit and the SCR catalyst outlet temperature sensor SIGNAL circuit. If a short circuit has been detected (less than 100k ohms), the aftertreatment SCR catalyst temperature sensor interface module must be replaced.

Refer to the wiring diagram for connector pin identification.

Install the aftertreatment SCR catalyst temperature sensor interface module and the two mounting capscrews.

NOTE: The arrow imprinted on the aftertreatment SCR catalyst temperature sensor interface module must be pointing in the same direction as the exhaust flow. Mounting the interface module incorrectly will result in the inability to connect the aftertreatment SCR catalyst system temperature sensors.

Tighten the two mounting capscrews.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Connect the aftertreatment SCR catalyst temperature sensor interface module to the OEM wiring harness, the aftertreatment SCR catalyst intake temperature sensor, and the aftertreatment SCR catalyst outlet temperature sensor.
• Connect the vehicle batteries. Refer to the OEM service manual.
• Operate the engine and check for proper operation.
• Use INSITE™ electronic service tool to check for active fault codes.