Cummins ISX11.9 CM2250 – Service Manual 019-253   Power Train Protection Switch

General Information

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The powertrain protection switch circuit signals the system to protect the drivetrain when lower gears are engaged. The powertrain protection feature can limit engine output torque depending upon transmission gear ratio. Engine torque limits based on transmission gear ratio can be adjusted using the INSITE™ electronic service tool.

 
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Resistance Check

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If INSITE™ electronic service tool is available, monitor the powertrain protection switch for proper operation. If
not, follow the troubleshooting procedures in this section.

Locate the powertrain protection switch. Remove and tag the two connectors from the terminals on the switch. Touch the multimeter probes to the terminals on the switch.

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Move the switch to the OFF position, and measure the resistance. The multimeter
must show an open circuit (100k ohms or more). If the circuit is
not open, the switch has failed. Refer to the original equipment manufacturer (OEM) troubleshooting and repair manual for the replacement instructions.

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Move the switch to the ON position, and measure the resistance. The multimeter
must show a closed circuit (10 ohms or less). If the circuit is
not closed, the switch has failed. Refer to the OEM troubleshooting and repair manual for the replacement instructions.

If the resistance value is correct, the switch
must still be checked for a short circuit to ground.

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Check for Short Circuit to Ground

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Touch one of the multimeter probes to one of the switch terminals. Touch the other probe to chassis ground. Move the switch to the ON position, and measure the resistance. The multimeter
must show an open circuit (100k ohms or more).

If the circuit is
not open, the switch has failed. Refer to the OEM troubleshooting and repair manual for replacement procedures.

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Check for Short Circuit to External Voltage Source

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 CAUTION 

The leads must fit tightly in the connector without expanding the pins in the connector otherwise the connector will be damaged.

Isolate the powertrain protection switch circuit. Turn the vehicle keyswitch to the ON position. Adjust the multimeter to measure VDC.

Insert the test lead connected to the positive (+) multimeter probe into the powertrain protection switch signal pin of the OEM harness.

Disconnect the negative (-) multimeter probe from the test lead, touch it to the engine block ground, and measure the voltage. The voltage
must be 1.5 VDC or less.

NOTE: An external voltage source is any wire in the OEM harness wiring that carries the voltage.

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If the voltage value is more than 1.5 VDC, there is a short circuit between the wire connected to the powertrain protection switch signal pin and a wire carrying power in the OEM harness. Repair the OEM harness according to the vehicle manufacturer’s procedures.

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Last Modified:  30-May-2008