M313C, M315C, M316C, M318C, M318C MH, M322C and M322C MH Excavators Electronic System Caterpillar

Limit Switches

Illustration 1	g00855687

Limit Switch (Service Brake Pedal)

Illustration 2	g00914468

The limit switch for the service brake pedal has three contacts. The ground wire A235-BK is connected to the ECM at contact J1-9. The normally closed contact on the switch is connected to the ECM at contact J1-56 (wire F790-BR). This indicates that the brake pedal is unlocked. The normally open contact on the switch is connected to the ECM at contact J1-57 (wire F787-GN). This switch is closed to ground when the brake pedal is fully depressed.

Limit Switch (Travel Pedal)

Illustration 3	g00920686

Note: The travel pedal limit switch is equipped on machines in serial number range 1 - 2000 for all prefixes covered in this manual. For machines above this S/N range, refer to Systems Operation, "Sensors" for information on updated components on the travel pedal.

The limit switch for the travel pedal has three contacts. The ground wire A235-BK is connected to the ECM at contact J1-9. The normally closed contact on the switch is connected to the ECM at contact J1-45 (wire M958-OR). This indicates that the travel pedal has not been pressed. The normally open contact on the switch is connected to the ECM at contact J1-44 (wire M957-GY). This switch is closed to ground when the travel pedal is fully depressed.

Limit Switch (Armrest)

Illustration 4	g00925920

The limit switch for the position of the armrest has three contacts. The ground wire A235-BK is connected to the ECM at contact J1-9. The normally closed contact on the switch is connected to the ECM at contact J1-55 (wire E918-GN). This indicates that the armrest is in the UP position. The normally open contact on the switch is connected to the ECM at contact J1-54 (wire E917-WH). This switch is closed to ground when the armrest is in the DOWN position.

Limit Switch (Boom)

The limit switch for the angle of the boom has three contacts. Two of these contacts are used. The ground wire A235-BK is connected to the ECM at contact J1-9. The normally closed contact on the switch is not connected. The normally open contact on the switch is connected to the ECM at contact J1-14 (wireE441-GN). This switch is closed to ground when the boom is fully lowered.

Limit Switch (HCR Door)

Illustration 5	g01153386

Note: The hydraulic cab riser switch is equipped on machines with the HCR attachment in the following serial number ranges: BDR2001-UP, BDM2001-UP, BDX2001-UP, BCZ2001-UP, BDK2001-UP, BDY2001-UP, BEB2001-UP, H2A1-UP, H2B1-UP, H2C1-UP, H2D1-UP, H2E1-UP, H2F1-UP and H2G1-UP.

The hydraulic cab riser door switch provides an input to the ECM that will indicate when the cab door is closed. When the door is closed, the switch is closed to ECM ground at contact J1-44 (wire E997-BR). The common terminal of the switch is connected to ECM ground at contact J1-9 (wire A235-BK). The ECM must detect this condition and other conditions before the cab can be raised.

Level Switches

Level Switch (Coolant Level)

Illustration 6	g00920674

The level switch is connected to the ECM at contact J1-15 (signal wire E452-WH) and contact J1-9 (ground wire A235-BK). When the fluid level drops below the switch, contact J1-15 is opened. The ECM sends the information on the CAN data link to the monitor. The monitor shows the appropriate message on the display.

Level Switch (Hydraulic Oil Level)

Illustration 7	g00986932

The level switch is connected to the ECM at contact J1-25 (signal wire 496-WH) and contact J1-9 (ground wire A235-BK). When the fluid level drops below the switch, contact J1-25 is opened. The ECM sends the information on the CAN data link to the monitor. The monitor shows the appropriate message on the display.

Pressure Switches

The following pressure switches are identical. The actuation pressure is 490 ± 49 kPa (71 ± 7 psi). The de-actuation pressure is 290 kPa (42 psi).

Illustration 8	g00855565

Note: The pressure switches for forward and reverse pilot pressure are equipped on machines that have serial numbers in the following ranges: BDR1-2000, BDM1-2000, BDX1-2000, BCZ1-2000, BDK1-2000, BDY1-2000 and BEB1-2000. For machines that are covered by this manual with a different serial number, refer to Systems Operation, "Sensors" or Systems Operation, "Auxiliary Hydraulic System" for information on updated components.

Pressure Switch (Multifunction Valve Reverse)

Illustration 9	g00925934
Forward pressure switch (1) and reverse pressure switch (2) in the multifunction valve (also referred to as the combined function valve)

Note: The pressure switches for multifunction valve forward and multifunction valve reverse are equipped on machines in the following serial number ranges: BDR1-2000, BDM1-2000, BDX1-2000, BCZ1-2000, BDK1-2000, BDY1-2000 and BEB1-2000. For machines that are covered by this manual with a different serial number, refer to Systems Operation, "Sensors" for information on updated components on the travel pedal.

The pressure switch for reverse flow in the multifunction valve is connected to the ECM at contact J2-31 (signal wire M747-OR) and contact J2-23 (ground wire 116-BR).

Pressure Switch (Multifunction Valve Forward)

Illustration 10	g00925934
(1) Forward pressure switch and (2) reverse pressure switch in the multifunction valve (also referred to as the combined function valve)

Note: The pressure switches for multifunction valve forward and multifunction valve reverse are equipped on machines in the following serial number ranges: BDR1-2000, BDM1-2000, BDX1-2000, BCZ1-2000, BDK1-2000, BDY1-2000 and BEB1-2000. For machines that are covered by this manual with a different serial number, refer to Systems Operation, "Sensors" for information on updated components on the travel pedal.

The pressure switch for forward flow in the multifunction valve is connected to the ECM at contact J2-30 (signal wire M748-GN) and contact J2-23 (ground wire 116-BR).

Pressure Switch (Forward Travel)

Illustration 11	g00915649

Note: The pressure switches for forward travel and reverse travel are equipped on machines that have serial numbers in the following ranges: BDR1-2000, BDM1-2000, BDX1-2000, BCZ1-2000, BDK1-2000, BDY1-2000 and BEB1-2000.

The pressure switch for forward travel is connected to the ECM at contact J1-28 (signal wire E480-BU) and contact J1-9 (ground wire A235-BK).

Pressure Switch (Reverse Travel)

Illustration 12	g00915658

The pressure switch for reverse travel is connected to the ECM at contact J1-30 (signal wire E482-WH) and contact J1-9 (ground wire A235-BK).

Pressure Switch (Swing Pilot)

Illustration 13	g00918410

The pressure switch for the swing circuit is connected to the ECM at contact J1-39 (signal wire G426-WH) and contact J1-9 (ground wire A235-BK). The ECM will use the input from this switch and from the main pump pressure switch in order to detect hydraulic activity. The ECM will use this information to determine when to enable the Automatic Engine Speed Control (AESC). For more information on the AESC function, refer to Systems Operation, "Automatic Engine Speed Control Function".

Pressure Switch (Main Pump)

Illustration 14	g00855565

Illustration 15	g01171832
Main pump pressure switch located on the manifold under the access panel behind the cab

The main pump pressure switch is connected to the ECM contact J1-31 (wire G424-GN) and contact J1-9 (ground wire A235-BK). The ECM will use the input from this switch and from the swing pressure switch in order to detect hydraulic activity. The ECM uses this information to determine when to enable the Automatic Engine Speed Control (AESC). For more information on the AESC function, refer to Systems Operation, "Automatic Engine Speed Control Function".

Pressure Switch (Brake Oil Accumulator)

Illustration 16	g00855587

Illustration 17	g00991163
Brake oil accumulator pressure switch location for machines in the following serial number ranges: BDR2001-UP, BDM2001-UP, BDX2001-UP, BCZ2001-UP, BDK2001-UP, BDY2001-UP,, BEB2001-UP, H2A1-UP, H2B1-UP, H2C1-UP, H2D1-UP, H2E1-UP, H2F1-UP and H2G1-UP.

Illustration 18	g01171337
Brake oil accumulator pressure switch location for machines in the following serial number ranges: BDR2001-UP, BDM2001-UP, BDX2001-UP, BCZ2001-UP, BDK2001-UP, BDY2001-UP,, BEB2001-UP, H2A1-UP, H2B1-UP, H2C1-UP, H2D1-UP, H2E1-UP, H2F1-UP and H2G1-UP.

The pressure switch for the brake oil accumulator is connected to the ECM at contact J1-16 (signal wire X778-PU) and contact J1-9 (ground wire A235-BK).

Pressure Switch (Quick Coupler)

Illustration 19	g00855596

Illustration 20	g00918471

The pressure switch for the quick coupler is connected to the ECM at contact J1-37 (signal wire P976-BR) and contact J1-9 (ground wire A235-BK). See Systems Operation, "Quick Coupler Function" for more information.

Pressure Switch (Service Brake)

Illustration 21	g00855612

Illustration 22	g00915673
Service brake pressure switch location for machines in the following serial number ranges: BDR1-2000, BDM1-2000, BDX1-2000, BCZ1-2000, BDK1-2000, BDY1-2000 and BEB1-2000.

Illustration 23	g01171351
Service brake pressure switch location for machines in the following serial number ranges: BDR2001-UP, BDM2001-UP, BDX2001-UP, BCZ2001-UP, BDK2001-UP, BDY2001-UP,, BEB2001-UP, H2A1-UP, H2B1-UP, H2C1-UP, H2D1-UP, H2E1-UP, H2F1-UP and H2G1-UP.

The pressure switch for the service brake is connected to the ECM at contact J1-47 (signal wire E973-GY) and contact J1-9 (ground wire A235-BK).

Switch (Overload Warning)

Illustration 24	g00855620

Illustration 25	g00925911

The pressure switch for overload warning is connected to the overload warning switch in the cab by wire H793-PU. The switch in the cab is connected to the machine ECM at contact J1-2 (wire E479-YL) and contact J1-9 (ground wire A235-BK). The overload warning switch can be adjusted. Refer to the following publications for more information:

• Testing and Adjusting, RENR6984, "M313C Excavator Hydraulic System"

• Testing and Adjusting, RENR6961, "M315C Excavator Hydraulic System"

• Testing and Adjusting, RENR5567, "M316C Excavator Hydraulic System"

• Testing and Adjusting, RENR5565, "M318C Excavator Hydraulic System"

• Testing and Adjusting, RENR7014, "M322C Excavator Hydraulic System"

Pressure Switch (Hydraulic Oil Filter)

Illustration 26	g00855630

Illustration 27	g00925939

The pressure switch that senses a restriction in the hydraulic oil system is connected to the ECM at contact J1-3 (signal wire E455-BR) and contact J1-9 (ground wire A235-BK).

Switch (Air Filter Restriction)

Illustration 28	g00991208

Illustration 29	g00991251

The pressure switch that senses a restriction in the air filter is connected to the ECM at contact J1-26 (signal wire 430-BU) and contact J1-9 (ground wire A235-BK).

Switch (Backup / Limp Home)

Illustration 30	g00855650

Illustration 31	g00920353

The backup / limp home switch places the machine in the limp home mode. The switch is connected to the ECM at contact J1-4 (signal wire F772-WH), contact J1-17 (signal wire F771-OR) and contact J1-9 (ground wire A235-BK). When the machine is in the limp home mode, power is reduced and many functions are inoperative. See Systems Operation, "Limp Home Function".

Switch (Fuel Pump)

Illustration 32	g00855751

Illustration 33	g00925940
(3) Fuel Pump Switch (4) Machine ECM

The fuel pump switch turns ON the fuel pump. The switch is connected to the ECM at contact J1-38 (signal wire L976-GN) and contact J1-9 (ground wire A235-BK). When the switch is pressed, the ECM checks various conditions before turning on the fuel pump. If the conditions are correct, the fuel pump will turn on. See Systems Operation, "Refueling Function" for more information.

Medium Pressure Switch

Illustration 34	g01154240
Medium pressure switch

Note: The medium pressure switch can be equipped on machines in the following serial number ranges: BDR2001-UP, BDM2001-UP, BDX2001-UP, BCZ2001-UP, BDK2001-UP, BDY2001-UP, BEB2001-UP, H2A1-UP, H2B1-UP, H2C1-UP, H2D1-UP, H2E1-UP, H2F1-UP and H2G1-UP.

The medium pressure switch is a three position switch that is used to select which function will be active in the medium pressure hydraulics system. The switch sends +battery power to the selected solenoid in order to enable the medium pressure function. The switch also provides a +battery input to the ECM at the same time that the solenoid is energized. The switch provides three inputs to the ECM that correspond to the three positions for the switch. The three ECM inputs are:

ECM contact J2-30 - Medium pressure sw 3 (Joystick steer)

ECM contact J2-31 - Medium pressure sw 1 (Med press enable)

ECM contact J2-38 - Medium pressure sw 2 (HCR/Offset boom)

Reference: For more information on the medium pressure hydraulic system, refer to Systems Operation, "Medium Pressure Hydraulic System".