16M Series 3 and 18M Series 3 Motor Grader Caterpillar

Electronic Control Modules

Implement ECM

Illustration 1	g03307257

Illustration 2	g01309473
ECM Connectors and Contacts

The Implement ECM determines actions that are based on input information and memory information. After the Implement ECM receives the input information, the ECM sends a corresponding response to the outputs. The inputs and outputs of the Implement ECM are connected to the machine harness by two 70 contact connectors (J1 and J2). The ECM sends the information to the Caterpillar Electronic Technician (Cat ET) on the Cat Data Link.

Note: The ECM is not serviceable. The ECM must be replaced if the ECM is damaged. Replace the ECM if a failure is diagnosed.

Implement #2 ECM

Illustration 3	g03307257

Illustration 4	g01309473
ECM Connectors and Contacts

The Implement #2 ECM determines actions that are based on input information and memory information. After the Implement #2 ECM receives the input information, the ECM sends a corresponding response to the outputs. The inputs and outputs of the Implement #2 ECM are connected to the machine harness by two 70 contact connectors (J1 and J2). The ECM sends the information to the Caterpillar Electronic Technician (Cat ET) on the Cat Data Link.

Note: The ECM is not serviceable. The ECM must be replaced if the ECM is damaged. Replace the ECM if a failure is diagnosed.

Implement #3 ECM

Illustration 5	g03307257

Illustration 6	g01309473
ECM Connectors and Contacts

The Implement #3 ECM determines actions that are based on input information and memory information. After the Implement #3 ECM receives the input information, the ECM sends a corresponding response to the outputs. The inputs and outputs of the Implement #3 ECM are connected to the machine harness by two 70 contact connectors (J1 and J2). The ECM sends the information to the Caterpillar Electronic Technician (Cat ET) on the Cat Data Link.

Note: The ECM is not serviceable. The ECM must be replaced if the ECM is damaged. Replace the ECM if a failure is diagnosed.

ECM Pull Up Voltage

In order to aid in diagnostics of certain types of electrical circuits that are controlled by the ECM, an internal "pull up voltage" is connected to ECM switch and sensor signal input contacts. An above normal voltage is internally connected to the ECM signal input circuit through a resister.

During normal operation, the switch or sensor signal will hold the circuit low or at a certain signal amplitude, however, circuit conditions such as a loss of power to the component, a disconnection, or an open circuit will allow the circuit to be pulled high by the ECM pull up voltage. This condition will result in an above normal voltage condition at the ECM contact. As a result, the ECM will activate an FMI 03 (voltage above normal) diagnostic code for the affected circuit.

The types of ECM input circuits that have pull up voltage present are:

• Pulse Width Modulated (PWM) sensor input circuits

• Switch to Ground Input switch input circuits

• Active analog (voltage) input signal circuits

• Passive analog (resistance) input signal circuits

ECM Pull Down Voltage

In order to aid in diagnostics of electrical circuits that are controlled by the ECM, an internal "pull down voltage" is connected to ECM switch to battery type input circuits.

During normal operation, the switch contacts that are allowing the connection to a voltage source will hold the circuit high. When circuit conditions such as a loss of power to the switch supply voltage, a disconnection in the switch circuit or an open circuit will allow the circuit to be pulled low by the ECM pull down voltage. This condition will result in a below normal voltage condition at the ECM contact. As a result, the ECM will activate an FMI 04 (voltage below normal) diagnostic code for the affected circuit.

Pin Locations

Inputs

The machine has several different types of input devices. The ECM receives machine status information from the input devices and determines the correct output action that is needed in order to control machine operations based on memory and software parameters. The machine utilizes the following types of inputs: switch type and sensor type.

Switches provide signals to the switch inputs of the ECM. The possible outputs of a switch are listed: an open signal, a grounded signal and + battery signal.

Sensors provide an electrical signal to the ECM that constantly changes. The sensor input to the ECM can be one of several different types of electrical signals such as: pulse width modulated (PWM) signals, voltage signals and frequency input signals. Each possible input to the ECM is listed in the tables for the 70-pin connectors.

Inputs provide information to the ECM in the form of sensors or switches.

Sensors

Sensors provide information to the ECM about the intent of the operator or changing conditions. The sensor signal changes proportionally to the changing of operator input or changing conditions. The following types of sensor signals are used by the ECM.

Frequency - The sensor produces a signal and the frequency (Hz) varies as the condition changes.

Pulse width modulated - The sensor produces a signal. The duty cycle of the signal varies as the condition changes. The frequency of this signal is constant.

Analog - The ECM measures the voltage that is associated to a specific condition of the control.

Hydraulic Oil Temperature Sensor

Illustration 7	g03547942

The hydraulic oil temperature sensor is a passive analog sensor. The sensor creates a different resistance depending on the temperature of the hydraulic oil. The variations in resistance cause a proportional variation in voltage. This voltage is measured at the ECM contact, and allows the ECM to determine the temperature of the hydraulic oil.

Right Hand Joystick

Illustration 8	g03545756

The right-hand joystick contains sensors for the following controls:

• Right-hand blade lift

• Blade sideshift

• Blade circle drive

• Blade pitch

• Circle sideshift

The sensors are all active pulse width modulated position type sensors. The blade sideshift position sensor is located in the base of the joystick and detects X-axis position. The right-hand blade lift sensor is located in the base of the joystick and detects Y-axis position. The blade circle drive sensor is located in the base of the joystick and detects the twist of the joystick. The circle sideshift sensor is located in the joystick handle and detects X-axis position of the thumb button. The blade pitch sensor is located in the joystick handle and detects Y-axis position of the thumb button. In the center position the duty cycle from each sensor is approximately 50%. As the joystick or thumb button is moved, the duty cycle of the sensor changes proportionally. Based on the duty cycles received the ECM is able to determine the operator request for right-hand joystick controls.

Left Hand Joystick

Illustration 9	g03866309

The left-hand joystick contains sensors for the following controls:

• Left-hand blade lift

• Left wheel lean

• Right wheel lean

• Articulation

The sensors are all active pulse width modulated position type sensors. The left-hand blade lift position sensor is located in the base of the joystick and detects Y-axis position. In the center position the duty cycle from each sensor is approximately 50%. As the joystick is moved, the duty cycle of the sensor changes proportionally. Based on the duty cycle received, the ECM is able to determine the operator request for left-hand blade lift.

The articulation position sensor is located in the base of the joystick and detects joystick twist position. In the center position the duty cycle of the sensor is approximately 50%. As the joystick is moved, the duty cycle of the sensor changes proportionally. Based on the duty cycle received, the ECM is able to determine the operator request for left or right articulation.

The left and right wheel lean sensors are located in the top of the joystick and detect the position of the two buttons. In the undepressed state the duty cycle from each sensor is approximately 50%. As the buttons are depressed, the duty cycle decreases proportionally. Based on the duty cycle received, the ECM is able to determine the operator request for wheel lean left and right.

Auxiliary Joystick Control

Illustration 10	g03556836

The auxiliary joystick control contains sensors for the following controls:

• Auxiliary pod control roller (lever 1)

• Auxiliary pod control roller (lever 2)

• Auxiliary pod control roller (lever 3)

• Auxiliary pod control roller (lever 4)

• Auxiliary pod control lever (lever 5)

• Auxiliary pod control lever (lever 6)

The sensors are all active pulse width modulated position type sensors. Auxiliary pod control rollers one through four are located in order as the finger rollers and sense the position of each roller. Auxiliary pod control lever five is located in the base of the center joystick and detects the Y-axis position of the joystick. Auxiliary pod control lever six is located in the base of the center joystick and detects the X-axis position of the joystick. In the center position the duty cycle from each sensor is approximately 50%. As the joystick or roller is moved, the duty cycle of the sensor changes proportionally. Based on the duty cycles received, the ECM is able to determine the operator request for right-hand joystick controls.

Alternate Auxiliary Joystick Control

Illustration 11	g03556958

The auxiliary joystick control contains sensors for the following controls:

• Auxiliary pod control roller (lever 7)

• Auxiliary pod control roller (lever 8)

The sensors are all active pulse width modulated position type sensors. Auxiliary pod control rollers seven and eight are located under the two finger rollers and sense the position of each roller. In the center position the duty cycle from each sensor is approximately 50%. As the roller is moved, the duty cycle of the sensor changes proportionally. Based on the duty cycles received, the ECM is able to determine the operator request for right-hand joystick controls.

Secondary Pressure Sensor

Illustration 12	g03325148

The secondary pressure sensor is a pulse width modulated sensor. The sensor monitors the pressure in the primary steering system. The duty cycle of the sensor is proportional to the pressure that the sensor measures.

Note: Only equipped on machines with European roading package.

Articulation Position Sensor

Illustration 13	g03569371

The articulation sensors are active pulse width modulated sensors. Both sensors are located in the same housing. The sensor varies the duty cycle of the output proportionally to the angle of articulation. The ECM uses the information to determine the angle of articulation of the machine.

Switches

Switches provide an open signal, a ground signal, or a +battery signal to the inputs of the ECM. Switches are open or closed.

• When a switch is open, no signal is provided to the corresponding input of the ECM. This “no signal” condition is also called “floating”.

• When a switch is closed, a ground signal or a +battery signal is provided to the corresponding input of the ECM.

Implement Lockout Switch

Illustration 14	g03346014

The implement lockout switch is a two pole switch. The switch has a normally connected and a normally open contact. When the switch is not depressed the normally connected contact is connected to the return, and the normally open contact floats to a high voltage state. When the switch is depressed, the normally open contact is connected to the return and the normally connected contact floats to a high voltage state. Based on the voltage state of the two ECM contacts, the ECM determines if the switch is depressed. The second pole on the switch allows the path of power from an ECM driver to flow through the switch to the shutoff solenoid.

Hydraulic Pilot Supply Filter Bypass Switch

Illustration 15	g03548458

The hydraulic pilot supply filter bypass switch is a single pole switch. The switch has an ECM contact that is normally open and floats to a high voltage state. When the switch closes, the contact is pulled to a low voltage state. The ECM monitors the voltage state of the switch to determine if the hydraulic pilot supply filter is being bypassed.

Hydraulic Pilot Return Filter Bypass

Illustration 16	g03563617

The hydraulic pilot return filter bypass switch is a single pole switch. The switch has an ECM contact that is normally open and floats to a high voltage state. When the switch closes, the contact is pulled to a low voltage state. The ECM monitors the voltage state of the switch to determine if the hydraulic pilot return filter is being bypassed.

Outputs

The ECM responds to decisions by sending electrical signals to the outputs. The outputs can create an action or the outputs can provide information to the operator or the service technician.

On/Off Solenoids

Blade Cushion Solenoids

Illustration 17	g03554156

The blade cushion solenoids are on/off type solenoids that control the operation of the blade cushion. The solenoids control the flow of oil to the blade cushion accumulators. When the solenoid is not energized, the flow is blocked to the accumulators.

Implement Pilot Pressure Supply

Illustration 18	g03554459

The implement pilot pressure supply solenoid is an on/off type solenoid that acts to lock out the implement system. The solenoid is part of the implement valve group and prevents pilot hydraulic oil from flowing to the rest of the valve bank. When the solenoid is energized, the pilot oil is allowed to flow and the implement system is enabled.

Note: The solenoid coils are not designed to operate using 24 DCV directly. The ECM sends a PWM signal of 24 V at a duty cycle that will provide the necessary current to the solenoid coils. Do NOT activate the coils by using 24 DCV (+battery). The life of the coils will be reduced drastically. A source of 12 DCV should be used, if the coils must be activated by not using the ECM.

Right and Left Blade Downforce Enable Solenoids

Illustration 19	g03664234

The right and left blade downforce enable solenoids are on/off type solenoids that act to enable or disable the blade downforce hydraulic circuitry. When the solenoid is energized, hydraulic oil is allowed to flow to the blade downforce hydraulic circuitry.

Note: The solenoid coils are not designed to operate using 24 DCV directly. The ECM sends a PWM signal of 24 V at a duty cycle that will provide the necessary current to the solenoid coils. Do NOT activate the coils by using 24 DCV (+battery). The life of the coils will be reduced drastically. A source of 12 DCV should be used, if the coils must be activated by not using the ECM.

Proportional Solenoids

Illustration 20	g03552417

All proportional solenoids in the primary implement system are identical in construction, however function differently. Illustration 20 shows an example of a proportional solenoid in the implement system.

Note: The solenoid coils are not designed to operate using 24 DCV directly. The ECM sends a PWM signal of 24 V at a duty cycle that will provide the necessary current to the solenoid coils. Do NOT activate the coils by using 24 DCV (+battery). The life of the coils will be reduced drastically. A source of 12 DCV should be used, if the coils must be activated by not using the ECM.

Blade Pitch Forward / Backwards Solenoids

There are two solenoids controlling the pitch of the blade. There is a forward and reverse solenoid. The two solenoids are identical in construction, and together control the operation of the blade pitch spool. The solenoids are proportional solenoids, and if the ECM sends a higher duty cycle signal to the pitch forward solenoid, that solenoid shifts the spool further in the FORWARD position. If the ECM sends a higher duty cycle signal to the pitch backwards solenoid, that solenoid shifts the spool further in the BACKWARD position. The two solenoids operate together to control the movement of the blade pitch spool.

Blade Sideshift Right/Left Solenoids

There are two solenoids controlling the sideshift of the blade. There is a right and left solenoid. The two solenoids are identical in construction, and together control the operation of the sideshift spool. The solenoids are proportional solenoids, and if the ECM sends a higher duty cycle signal to the sideshift right solenoid, that solenoid shifts the spool further in the RIGHT position. If the ECM sends a higher duty cycle signal to the sideshift left solenoid, that solenoid shifts the spool further in the LEFT position. The two solenoids operate together to control the movement of the sideshift spool.

Wheel Lean Right / Left Solenoids

There are two solenoids controlling the lean of the wheels. There is a right and left solenoid. The two solenoids are identical in construction, and together control the operation of the wheel lean spool. The solenoids are proportional solenoids, and if the ECM sends a higher duty cycle signal to the wheel lean right solenoid, that solenoid shifts the spool further in the RIGHT position. If the ECM sends a higher duty cycle signal to the wheel lean left solenoid, that solenoid shifts the spool further in the LEFT position. The two solenoids operate together to control the movement of the wheel lean spool.

Circle Right / Left Solenoids

There are two solenoids controlling the spin of the circle. There is a right and left solenoid. The two solenoids are identical in construction, and together control the operation of the circle rotation spool. The solenoids are proportional solenoids, and if the ECM sends a higher duty cycle signal to the spin right solenoid, that solenoid shifts the spool further in the RIGHT position. If the ECM sends a higher duty cycle signal to the spin left solenoid, that solenoid shifts the spool further in the LEFT position. The two solenoids operate together to control the movement of the circle rotation spool.

Circle Sideshift Right / Left Solenoids

There are two solenoids controlling the shift of the circle. There is a right and left solenoid. The two solenoids are identical in construction, and together control the operation of the circle sideshift spool. The solenoids are proportional solenoids, and if the ECM sends a higher duty cycle signal to the circle sideshift right solenoid, that solenoid shifts the spool further in the RIGHT position. If the ECM sends a higher duty cycle signal to the circle sideshift left solenoid, that solenoid shifts the spool further in the LEFT position. The two solenoids operate together to control the movement of the circle sideshift spool.

Blade Right Raise / Lower Solenoids

There are two solenoids controlling the height of the right side of the blade. There is a raise and lower solenoid. The two solenoids are identical in construction, and together control the operation of the right side raise / lower spool. The solenoids are proportional solenoids, and if the ECM sends a higher duty cycle signal to the raise solenoid, that solenoid shifts the spool further in the RAISE position. If the ECM sends a higher duty cycle signal to the lower solenoid, that solenoid shifts the spool further in the LOWER position. The two solenoids operate together to control the movement of the right side raise / lower spool.

Blade Left Raise / Lower Solenoids

There are two solenoids controlling the height of the left side of the blade. There is a raise and lower solenoid. The two solenoids are identical in construction, and together control the operation of the left side raise / lower spool. The solenoids are proportional solenoids, and if the ECM sends a higher duty cycle signal to the raise solenoid, that solenoid shifts the spool further in the RAISE position. If the ECM sends a higher duty cycle signal to the lower solenoid, that solenoid shifts the spool further in the LOWER position. The two solenoids operate together to control the movement of the left side raise / lower spool.

Articulate Left / Right Solenoids

There are two solenoids controlling the articulation of machine. There is a left and right solenoid. The two solenoids are identical in construction, and together control the operation of the articulation spool. The solenoids are proportional solenoids, and if the ECM sends a higher duty cycle signal to the left solenoid, that solenoid shifts the spool further in the LEFT position. If the ECM sends a higher duty cycle signal to the right solenoid, that solenoid shifts the spool further in the RIGHT position. The two solenoids operate together to control the movement of the left side raise / lower spool.

Auxiliary Valve Port A / B Solenoid

There are two solenoids controlling the auxiliary valve. There is an "A"and "B" solenoid. The two solenoids are identical in construction, and together control the operation of the auxiliary spool.

Right and Left Blade Downforce Solenoids

Illustration 21	g03664305

The right and left blade downforce solenoids independently control the right and left side relief valves. The two solenoids are identical in construction. The solenoids are proportional solenoids, and if the ECM sends a higher duty cycle signal to one of the solenoids, the pressure setting of the relief valve is proportionally increased. If the ECM sends a lower duty cycle signal to one of the solenoids, the pressure setting of the relief valve is proportionally decreased. The two solenoids independently control the downforce of the right and left sides of the blade.

Data Link

Electronic communication between the Transmission / Chassis ECM, the Implement ECM, and the other control modules on the machine is conducted over data link circuits. The data link circuits allow the sharing of information with other electronic control modules. The data link circuits are bidirectional. The data link circuit allows the ECM to send information and to receive information.

The electronic communication system consists of two types of data link systems.

• Cat Data Link

• SAE J1939 (CAN) Data Link

The two types of data links are the main structure for communication between all of the control modules on the machine.

The SAE J1939 Data Link circuit is mostly used for faster operational communication between the control modules on the machine. The Cat Data Link is used for some of the internal communication that does not require the faster speeds and is used for communication with external devices such as the Caterpillar Electronic Technician (Cat ET) service tool.

Cat Data Link

The Cat Data Link is an input/output of the ECM. The data link uses the connector for the service port in order to communicate with the Caterpillar Electronic Technician. A data link connection is provided for the product link.

Note: The control for the product link provides a global positioning system for the machine.

The data link is bidirectional. The bidirectional link allows the ECM to input information and output information. The data link consists of the following parts: internal ECM circuits, the related harness wiring, the service tool connector and the connector for the product link. The Cat Data Link connects to the ECM at contact J1-10 (wire 893-GN(Green)) and contact J1-20 (wire 892-BR(Brown)).

• The ECM receives commands from the Cat ET in order to change the operating modes. The Cat ET will read the service codes that are stored in the memory of the ECM. The Cat ET will clear the service codes that are stored in the memory of the ECM.

• The ECM sends the input and the output information to the Caterpillar ET.

Note: An electronic control module that uses the Cat Data Link will have a module identifier. The MID for the Machine Electronic Control Module is 039.

CAN Data Link

A data link is required for communication with the service tool (Cat ET) and the electronic control modules as well as instrument clusters and other devices that use this communications protocol. The data link is not used in order to broadcast any diagnostic information.