993K Wheel Loader Power Train Caterpillar

Switches

STIC Control

Illustration 1	g01444766

Upshift

The upshift switch tells the ECM that the operator wants the transmission to upshift one gear. The ECM will log a diagnostic code of CID 0622 for the switch.

Table 1

Switch Status
Position	Normally Open	Normally Closed
Depressed	Closed	Open
Released	Open	Closed

Downshift

The downshift switch tells the ECM that the operator wants the transmission to downshift one gear. The ECM will log a diagnostic code of CID 0621 for the switch.

Table 2

Switch Status
Position	Normally Open	Normally Closed
Depressed	Closed	Open
Released	Open	Closed

Direction

The direction switch has three positions: forward, neutral and reverse. The operator selects the direction of the transmission through the switch. The ECM will log a diagnostic code of CID 0623 for the switch.

Table 3

Switch Status
Position	Reverse	Neutral	Forward
Reverse	Closed	Open	Open
Neutral	Open	Closed	Open
Forward	Open	Open	Closed

Steering and Transmission Lock

Illustration 2	g01444768

The switch tells the ECM when the operator has the lock lever in the locked position. The ECM will log a diagnostic code of CID 0626 for the switch.

Table 4

Switch Status
Switch Position	Normally Open	Normally Closed
Locked	Closed	Open
Unlocked	Open	Closed

Parking Brake

Illustration 3	g01444770

The operator uses the parking brake switch in order to set the brake. The ECM sets the brake if the operating conditions of the machine are appropriate. The ECM will log a diagnostic code of CID 0070 for the switch.

Table 5

Switch Status
Switch Position	Normally Open	Normally Closed
Out	Closed	Open
In	Open	Closed

Parking Brake Pressure

Illustration 4	g01444773

The parking brake pressure switch provides the ECM with information about the hydraulic portion of the parking brake assembly. The parking brake is applied by a spring. The parking brake is released by hydraulic pressure. The parking brake is ON when the pressure switch is not actuated. The parking brake is OFF when the pressure switch is actuated. The ECM will log a diagnostic code of CID 0627 for the switch.

Table 6

Switch Status
Switch Position	Normally Open	Normally Closed
High Pressure	Closed	Open
Low Pressure	Open	Closed

Lockup Clutch (Attachment)

Illustration 5	g01444776

The switch tells the ECM that the operator wants to enable the lockup clutch. The switch tells the ECM that the operator wants to disable the lockup clutch.

Table 7

Switch Status
Switch Position	Normally Open
On	Closed
Off	Open

Ride Control (Attachment)

Illustration 6	g01444777

The ride control switch tells the ECM that the operator has selected a mode. The ECM will log a diagnostic code of CID 0367 for the switch.

Table 8

Switch Status
Switch Position	Switch 2	Switch 1
On	Ground	Open
Off	Ground	Ground
Auto	Open	Ground

Quickshift

Illustration 7	g01444778

The switch tells the ECM when the operator selects the quickshift function. The ECM will log a diagnostic code of CID 0628 for the switch.

Table 9

Switch Status
Switch Position	Normally Open	Normally Closed
On	Closed	Open
Off	Open	Closed

Reduced Rimpull

Illustration 8	g01444780

The switch allows the operator to select one of the four levels that are available for rimpull. The ECM will log a diagnostic code of CID 0138 for the switch.

Table 10

Switch Status
Switch Position	#1	#2	#3	#4
Large Dot	Ground	Open	Open	Open
Third Dot	Open	Ground	Open	Open
Second Dot	Open	Open	Ground	Open
Small Dot	Open	Open	Open	Ground

Manual Autolube (Attachment)

Illustration 9	g01444782

The switch manually activates the lubrication system. The autolube will perform the number of manual lube cycles that is specified by the setting for the manual lube cycle.

Table 11

Switch Status
Switch Position	Normally Open
Momentarily On	Closed
Off	Open

Transmission Lockout (Ground Level)

Illustration 10	g01444783

The switch locks out the transmission with a padlock as a safety measure. The switch is located at the service center on the bumper. The ECM will log a diagnostic code of CID 0348 for the switch.

Table 12

Switch Status
Switch Position	Normally Open	Normally Closed
On	Closed	Open
Off	Open	Closed

Transmission Oil Level

Illustration 11	g01444784

The switch indicates that the oil is low while the machine is running.

Table 13

Switch Status
Switch Position	Normally Open
Off	Closed
On	Open

Heated Mirror (Attachment)

Illustration 12	g01444785

The switch activates the function for the heated mirror for five minutes. During the five minutes, any additional pressing of the switch will be ignored. The timer for the heated mirror cannot be stopped. The timer for the heated mirror cannot be restarted.

Table 14

Switch Status
Switch Position	Normally Open
Momentarily On	Closed
Off	Open

HVAC Blower and Air Condition On/Off

Illustration 13	g01444787
On/Off switch

Illustration 14	g01444789
Blower switches

The switches are connected in series. The switches are an input to the ECM. The switches activate the compressor. The switches deactivate the compressor.

Table 15

Switch Status
Switch Position	Normally Open contact (J2-31)
On	Closed
Off	Open

Limit for Powered Access (Attachment)

Illustration 15	g01444791

The switch indicates the position of the lift. The switch will show that the lift is raised or that the lift is out of the raised position. The ECM will log a diagnostic code of CID 2678 for the switch.

Table 16

Switch Status
Switch Position	Normally Open contact (J2-31)	Normally Open contact (J2-59)
Lowered	Closed	Open
Raised	Open	Closed

Shutoff for the Right Implement Valve

Illustration 16	g01445486

The switch tells the ECM that the shutoff valve is in the closed position. The ECM will prevent starting when the valve is in the closed position. The ECM will log a diagnostic code of CID 2681 for the switch.

Table 17

Switch Status
Switch Position	Normally Open contact (J2-42)	Normally Open contact (J2-43)
Closed Valve	Closed	Open
Open Valve	Open	Closed

Shutoff for the Center Implement Valve

Illustration 17	g01445488

The switch tells the ECM that the shutoff valve is in the closed position. The ECM will prevent starting when the valve is in the closed position. The ECM will log a diagnostic code of CID 2680 for the switch.

Table 18

Switch Status
Switch Position	Normally Open contact (J2-40)	Normally Open contact (J2-41)
Closed Valve	Closed	Open
Open Valve	Open	Closed

Sensors

Transmission Input Speed

Illustration 18	g01445489

The transmission input speed sensor tells the ECM the speed of the input shaft of the transmission. The ECM will log a diagnostic code of CID 0672 for the transmission input speed sensor.

Transmission Output Speed

Illustration 19	g01445492

The transmission output speed sensors detect the speed in the output shafts in the drop box of the transmission. Information about the transmission output speed is broadcast on the Cat data link. Two sensors are required for detecting directional changes in order to ensure accurate clutch slippage for engaging the impeller clutch. Diagnostic codes that are associated with the output speed sensors will remain active until a valid transmission output speed is detected on the failed sensor. The ECM will log a diagnostic code of CID 0585 for the first transmission output speed sensor. The ECM will log a diagnostic code of CID 0673 for the second transmission output speed sensor.

Position of Torque Converter Pedal

Illustration 20	g01445493

The pedal position sensor determines the position of the torque converter pedal. The sensor sends a PWM signal to the ECM. The ECM monitors the signal. Then, the ECM calculates the position of the pedal from the signal. Information about the transmission output speed is broadcast on the Cat data link. The ECM will log a diagnostic code of CID 1712 for the torque converter pedal position sensor.

Impeller Clutch Pressure

Illustration 21	g01445500

The sensor determines the pressure of the impeller clutch. The sensor sends a PWM signal to the ECM. The ECM monitors the signal. Then, the ECM calculates the pressure from the signal. Information about the impeller clutch pressure is broadcast on the Cat data link. The ECM will log a diagnostic code of CID 0603 for the torque converter pedal position sensor.

Autolube Pressure

Illustration 22	g01445502

The sensor determines the pressure of the auto lubrication system. The sensor sends a signal to the ECM. The ECM monitors the signal. Then, the ECM calculates the pressure from the signal. The ECM will log a diagnostic code of CID 0379 for the autolube pressure sensor.

Grease Level for Autolube

Illustration 23	g01445503

The sensor determines the level of grease in the auto lubrication system. The sensor tells the ECM the amount of grease that is available. The sensor is an analog sensor. The sensor is composed of a rod and ten resistors that are controlled by switches. A float travels along the rod. As the float moves down the rod, the float passes below a switch. The switch opens and the associated resistor is added in series to the total resistance. The grease level is full when all of the switches are closed. The grease level is low when all of the switches are open. The ECM will log a diagnostic code of CID 1022 for the autolube grease level sensor.

Transmission Oil Temperature

Illustration 24	g01445505

The sensor monitors the oil temperature at the inlet of the transmission control. The temperature is used in order to calibrate the impeller clutch. The temperature must be above 40 °C (104 °F). The ECM will log a diagnostic code of CID 0177 for the oil temperature sensor.

Transmission Pressure

Illustration 25	g01445506

The sensor monitors the transmission pump pressure. The ECM will log a diagnostic code of CID 0862 for the pump pressure sensor.

Wire for Tachometer

The Engine ECM drives the frequency for this input. The frequency is related to the actual engine rpm. The ECM will log a diagnostic code of CID 0190 for the engine speed sensor.