ARM AS 2641153 - Caterpillar

Note: The normally closed (N/C) circuit and normally open (N/O) circuit of the secondary steering pressure switch are used for diagnostic purposes. A circuit failure is present if the two circuits are open at the same time or if the two circuits are grounded at the same time. This fault is then shown on the display of the Transmission ECM.Reference: For more information on the diagnostic operations, refer to Systems Operation, "Power Train Electronic Control System" for the machine that is being serviced.Reference: For more information on the secondary steering system, refer to Systems Operation, "Secondary Steering System" for the machine that is being serviced.Reference: For more information on the function of the Transmission ECM, refer to Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.Transmission Filter Bypass Switch
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Transmission Filter Bypass Switch
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Transmission Filter Bypass Switch
The Transmission Filter Bypass Switch provides a switch to ground input to the Transmission ECM. The switch is used to determine if the transmission oil filter is restricted and requires replacement.The contacts of the bypass switch are normally closed. Restrictions in the filter will cause a difference in the inlet oil pressure between the filter inlet port and the outlet port. The switch contacts will open and the ECM will activate an event code if the following conditions exist.
The oil pressure difference reaches the pre-set trigger pressure
The oil temperature is greater than 52° C (126° F).When these conditions are present, the ECM will activate a level 2, E329 Event (Transmission Filter Plugged) to alert the operator that the filter requires service.When the event is activated, the event will be latched active. The event can be “snoozed” for 1 hour before being displayed again. The key start switch must be cycled OFF and then the engine must be started to reset the event.When the engine is operating and oil is flowing, the ECM cannot determine the difference between the open switch contacts or an open condition in the switch circuit. For troubleshooting, if the event is activated when the engine is in operation, always confirm that the diagnostic code does not become active with engine and the key start switch ON. If the diagnostic code is activated under these conditions, check the switch circuits for opens or poor connections before changing the filter.Sensors
Sensors provide information to the Transmission electronic control module (ECM) about changing conditions. The sensor signal changes proportionally to the changing conditions. The following types of sensor signals are recognized by the Transmission ECM:
Frequency signals: The frequency (Hz) of the sensor signal varies as the condition changes.
Pulse width modulated signals (PWM): The duty cycle of the sensor signal varies as the condition changes. The frequency of this signal is constant.
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Pulse Width Modulated Signal
Transmission Output Speed Sensor
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Speed Sensor
The Transmission Output speed sensor is an input of the Transmission ECM. This speed sensor is a frequency sensor. Frequency sensors produce a signal (Hz) which varies as the condition changes. The sensor generates an approximate sine wave