Speed Control - Service Information Jeep Grand Cherokee WK2

DESCRIPTION

Two electronic speed control systems are available factory-installed equipment on this vehicle: a conventional system and an adaptive system. Additional details of these two systems and their components can be found under the subheadings and paragraphs that follow.

CONVENTIONAL SPEED CONTROL

The standard equipment conventional electronic speed control system includes the following major components, which are described in further detail elsewhere in this service information

1. Antilock Brake Module - An Antilock Brake Module (ABM) (also known as Controller Antilock Brake/CAB or the Electronic Stability Control/ESC module) is located on the antilock brake Hydraulic Control Unit (HCU) in the engine compartment. Refer to «MODULE, ANTI-LOCK BRAKE SYSTEM , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/communication-devices/#electronic-control-modules-service-information) .
2. Brake Lamp Switch - The brake (also known as stop) lamp switch is located on the brake pedal support bracket under the driver side of the instrument panel. Refer to «SWITCH, STOP LAMP , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/exterior-lights/#lampslighting-exterior-service-information) .
3. ElectroMechanical Instrument Cluster - A CRUISE indicator is located in the fixed segment display of the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) that provides an indication to the vehicle operator when the speed control system is turned ON. Refer to «DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/gauges-instrument-panels/#instrument-cluster-service-information__description) .
4. Powertrain Control Module - The Powertrain Control Module (PCM) located on the Totally Integrated Power Module (TIPM) in the right front corner of the engine compartment contains the software and hardware that monitors all of the speed control system inputs and controls all of the speed control system outputs. Refer to «MODULE, POWERTRAIN CONTROL , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/communication-devices/#electronic-control-modules-service-information) .
5. Speed Control Switches - A speed control switch pod containing four momentary switch push buttons is located in the right horizontal spoke of the steering wheel.
6. Steering Control Module - A Steering Control Module (SCM) is integral to the Steering Column Control Module (SCCM) located at the top of the steering column just below the steering wheel. Refer to «MODULE, STEERING COLUMN , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/communication-devices/#electronic-control-modules-service-information) .
7. Wheel Speed Sensors - A wheel speed sensor is located on the knuckle of each front and rear wheel. Refer to «SENSOR, WHEEL SPEED, FRONT , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/anti-locktraction-control/#antilock-brake-system-abs-service-information) .

The ABM, the EMIC, the PCM and the SCM each contain a microprocessor and programming that allow them to communicate with each other using the Controller Area Network (CAN) data bus. This method of communication is used by the SCM to relay the status of the speed control switches to the PCM, and by the PCM for control of the CRUISE indicator in the EMIC. Refer to COMMUNICATION , DESCRIPTION .

Hard wired circuitry connects the conventional electronic speed control system components to the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other, to the vehicle electrical system and to the speed control system components through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.

ADAPTIVE SPEED CONTROL

The optional equipment adaptive electronic speed control system includes the following major components, which are described in further detail elsewhere in this service information

1. Adaptive Speed Control Sensor - An adaptive speed control sensor (also known as the Adaptive Cruise Control/ACC sensor or module and the radar sensor or module) is located on a bracket secured near the center of the underside of the front bumper support member of the Front End Module (FEM) behind the front fascia. Refer to «SENSOR AND BRACKET, ADAPTIVE SPEED CONTROL , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/communication-devices/#electronic-control-modules-service-information) .
2. Antilock Brake Module - An Antilock Brake Module (ABM) (also known as Controller Antilock Brake/CAB or the Electronic Stability Control/ESC module) is located on the antilock brake Hydraulic Control Unit (HCU) in the engine compartment. Refer to «MODULE, ANTI-LOCK BRAKE SYSTEM , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/communication-devices/#electronic-control-modules-service-information) .
3. Brake Lamp Switch - The brake (also known as stop) lamp switch is located on the brake pedal support bracket under the driver side of the instrument panel. Refer to «SWITCH, STOP LAMP , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/exterior-lights/#lampslighting-exterior-service-information) .
4. ElectroMechanical Instrument Cluster - A CRUISE indicator is located in the fixed segment display of the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) that provides an indication to the vehicle operator when the speed control system is turned ON. Refer to «DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/gauges-instrument-panels/#instrument-cluster-service-information__description) .
5. Electronic Vehicle Information Center - The Electronic Vehicle Information Center (EVIC) is located in the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) and provides an interface to the vehicle operator for setting the adaptive speed control customer preferences as well as a display of the adaptive speed control and Forward Collision Warning (FCW) system status messages. Refer to «CENTER, ELECTRONIC VEHICLE INFORMATION , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/communication-devices/#message-center-service-information__description) .
6. Powertrain Control Module - The Powertrain Control Module (PCM) located on the Totally Integrated Power Module (TIPM) in the right front corner of the engine compartment contains the software and hardware that monitors all of the speed control system inputs and controls all of the speed control system outputs. Refer to «MODULE, POWERTRAIN CONTROL , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/communication-devices/#electronic-control-modules-service-information) .
7. Speed Control Switches - A speed control switch pod containing six momentary switch push buttons is located in the right horizontal spoke of the steering wheel.
8. Steering Control Module - A Steering Control Module (SCM) is integral to the Steering Column Control Module (SCCM) located at the top of the steering column just below the steering wheel. Refer to «MODULE, STEERING COLUMN , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/communication-devices/#electronic-control-modules-service-information) .
9. Wheel Speed Sensors - A wheel speed sensor is located on the knuckle of each front and rear wheel. Refer to «SENSOR, WHEEL SPEED, FRONT , DESCRIPTION»(/jeep/grand-cherokee/wk2-2010-2013/remont/anti-locktraction-control/#antilock-brake-system-abs-service-information) .

The ACC sensor, the ABM, the EMIC, the EVIC, the PCM and the SCM each contain a microprocessor and programming that allow them to communicate with each other using the Controller Area Network (CAN) data bus. This method of communication is used by the ACC sensor to provide inputs to the ABM, the EVIC and the PCM, is used by the ABM to provide inputs to the PCM, is used by the SCM to relay the status of the speed control switches to the PCM and is used by the PCM for control of the indicators in the EMIC and the indications in the EVIC. Refer to COMMUNICATION , DESCRIPTION .

Hard wired circuitry connects the adaptive electronic speed control system components to the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other, to the vehicle electrical system and to the speed control system components through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.

The vehicle operator controls all conventional speed control system features through the speed control switch pod on the face of the right horizontal spoke of the steering wheel. When a push button of the switch pod is depressed, it provides a hard wired resistor multiplexed analog input to the Steering Control Module (SCM).

The SCM reads the speed control switch input, then relays an electronic speed control switch status message to the Powertrain Control Module (PCM) over the Controller Area Network (CAN) data bus. The PCM software continually monitors these inputs as well as electronic vehicle distance message inputs from the Antilock Brake Module (ABM) (also known as the Controller Antilock Brake/CAB, the Electronic Stability Control/ESC module or the Antilock Brake System/ABS module) and numerous hard wired inputs including the brake (or stop) lamp switch, then provides the appropriate electronic message and hard wired outputs to invoke the requested electronic speed control features.

The PCM microprocessor continuously monitors all of the speed control system electrical circuits to determine the system readiness. If the PCM detects a monitored system fault, it sets and stores a Diagnostic Trouble Code (DTC). The PCM uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the CAN data bus. This method of communication is used for control of the Malfunction Indicator Lamp (MIL) (also known as the Check Engine lamp) in the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) and for system diagnosis and testing through the 16-way data link connector located on the driver side lower edge of the instrument panel.

The hard wired inputs and outputs for the PCM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the PCM or the electronic controls or communication between other modules and devices that provide features of the conventional speed control system. The most reliable, efficient, and accurate means to diagnose the PCM or the electronic controls and communication related to speed control system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

The vehicle operator controls all adaptive speed control system features through the speed control switch pod on the face of the right horizontal spoke of the steering wheel. When a push button of the switch pod is depressed, it provides a hard wired resistor multiplexed analog input to the Steering Control Module (SCM).

The SCM reads the speed control switch input, then relays an electronic speed control switch status message to the Powertrain Control Module (PCM) and to the adaptive speed control sensor (also known as the Adaptive Cruise Control/ACC sensor or module, or as the radar sensor or module) over the Controller Area Network (CAN) data bus. The PCM and ACC sensor microprocessors continually monitor these inputs as well as electronic wheel speed message inputs from the Antilock Brake Module (ABM) (also known as the Controller Antilock Brake/CAB, the Electronic Stability Control/ESC module or the Antilock Brake System/ABS module), electronic gear selector message inputs from the Transmission Control Module TCM and numerous hard wired inputs including the brake (or stop) lamp switch, then provides the appropriate electronic message and hard wired outputs to invoke the requested electronic speed control features.

Using the MODE push button of the speed control switch pod on the face of the right horizontal spoke of the steering wheel, the vehicle operator can choose between adaptive speed control and conventional speed control modes of operation. As the name implies, when in the conventional speed control mode the speed control system is used and functions exactly like a conventional speed control system. When in the adaptive speed control mode, the vehicle operator can use the DISTANCE push button of the speed control switch pod to select from one of three distance settings for the adaptive cruise system to maintain. These settings equate to the time in seconds separating the vehicle from a preceding vehicle. The ACC sensor then uses electronic message outputs to the ABM, the TCM and the PCM to maintain the selected separation distance. The available distance settings are

1. 1 - 1.0 second
2. 2 - 1.5 seconds
3. 3 - 2.0 seconds

The PCM and ACC sensor microprocessors continuously monitor all of the speed control system electrical circuits to determine the system readiness. If the PCM or ACC sensor detects a monitored system fault, it sets and stores a Diagnostic Trouble Code (DTC). The PCM and ACC sensor use On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the CAN data bus. This method of communication is used for control of the Malfunction Indicator Lamp (MIL) (also known as the Check Engine lamp) in the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) and for system diagnosis and testing through the 16-way data link connector located on the driver side lower edge of the instrument panel.

The hard wired inputs and outputs for the PCM and the ACC sensor may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the PCM, the ACC sensor or the electronic controls or communication between other modules and devices that provide features of the adaptive speed control system. The most reliable, efficient, and accurate means to diagnose the PCM, the ACC sensor or the electronic controls and communication related to speed control system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

Scheme 1

Scheme 2

The speed control switch pod (1) is located in the right spoke of the steering wheel spoke bezel. Two different switches are used. One switch has four buttons and is used on vehicles not equipped with the optional adaptive speed control (also known as the Adaptive Cruise Control/ACC) system. The other switch has six buttons and is used on vehicles equipped with the ACC system option. These switches are the primary control used by the vehicle operator to manage the particular speed control system installed in the vehicle. The only visible components of the switch pod are the switch push buttons and a decorative bezel around the push buttons, which stands slightly proud of the steering wheel spoke bezel. The remainder of the switch pod including its mounting provisions and its electrical connection are concealed beneath the spoke bezel.

The switch pod housing and push buttons are constructed of molded plastic. Each of the push buttons has white International Control and Display Symbol graphics or text applied to it, which clearly identify the function of each push button. The switch pod is secured through three integral mounting tabs (2) to mounting bosses on the back of the spoke bezel by three screws. A connector receptacle (3) integral to the inboard end of the switch pod housing connects the speed control switch and the Local Interface Network (LIN) slave node circuitry integral to the switch pod to the vehicle electrical system through a dedicated take out and connector of the steering wheel wire harness.

The speed control switch pod cannot be adjusted or repaired. If any function of the switch or the LIN slave node is ineffective or damaged, the entire switch pod unit must be replaced.

OPERATION

The speed control switch pod is a resistor multiplexed unit that provides hard wired inputs to the Steering Control Module (SCM) microprocessor integral to the Steering Column Control Module (SCCM). The speed control switch pod also contains the circuitry of a Local Interface Network (LIN) slave node, which provides source current for and communicates the switch or sensor states of the Electronic Vehicle Information Center (EVIC) switches, the remote radio switches, the paddle shifter switches (if equipped), the horn switch and the heated steering wheel sensor (if equipped) over the LIN data bus to the SCM, which is the LIN master node.

The speed control switch pod for vehicles equipped with a conventional electronic speed control system and not equipped with the optional adaptive speed control (also known as the Adaptive Cruise Control/ACC) system contains four switch push buttons whose functions are

1. On/Off - This switch button enables or disables the speed control system and clears any previous speed control set speed from system memory.
2. Resume / + - This switch button restores the vehicle to a previously stored set speed or accelerates the vehicle from an already attained set speed.
3. Cancel - This switch button cancels the current speed control event, but does not turn the system OFF or clear the currently stored set speed.
4. Set / - - This switch button sets the current vehicle speed as the stored set speed or decelerates (coasts) the vehicle to a speed that is slower than the already attained set speed.

The optional adaptive speed control switch pod for vehicles equipped with the ACC system option contains the same four switch push buttons as the conventional speed control switch pod, then adds two buttons whose functions are

1. Mode - This switch button toggles the speed control system between adaptive (ACC) or conventional (non-ACC) modes of operation.
2. Distance - This switch button selects the separation or following distance (in seconds) that the ACC system maintains between this vehicle and any preceding vehicle. The three distance settings available are: 1 - about 1.0 second, 2 - about 1.5 seconds or 3 - about 2.0 seconds.

The SCM LIN master node provides a clean ground and fused B(+) current for all of the switches and sensors on the rotating steering wheel through the LIN slave node circuitry of the speed control switch pod as well as for the Light Emitting Diode (LED) back lighting of both the speed control and the EVIC switch pods. The SCM continually monitors all of the hard wired speed control switch circuits as well as the LIN bus data. The SCM will set a Diagnostic Trouble Code (DTC) for any problem it detects in the speed control switch circuits, and will store a Signal Not Available (SNA) code for any LIN bus input errors. The SCM also communicates with other electronic modules over the Controller Area Network (CAN) data bus. Therefore, any SCM DTC information can be retrieved using a diagnostic scan tool connected to the Data Link Connector (DLC).

The analog resistor multiplexed circuits of the speed control switch pod as well as the hard wired circuits between the switch pod and the SCM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the LIN slave or master nodes, the SCM, the SCCM or the electronic controls and communication between modules and other devices that provide some features of the speed control system. The most reliable, efficient, and accurate means to diagnose the speed control switch pod, the LIN slave or master nodes, the SCM or the electronic controls and communication related to speed control system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

DIAGNOSIS AND TESTING

Scheme 3

Note. The following test confirms only correct speed control switch functions. It does not test or confirm any of the Local Interface Network (LIN) slave node inputs, outputs or functions. LIN slave node testing requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

1. Remove the speed control switch pod from the steering wheel. Refer to «SWITCH, SPEED CONTROL , REMOVAL»(/jeep/grand-cherokee/wk2-2010-2013/remont/cruise-control-systems/#speed-control-service-information__removal) .
2. Disconnect the steering wheel wire harness connector from the back of the speed control switch pod.
3. Using an ohmmeter, test the resistance between the terminals of the switch as shown in the Speed Control Switch Tests table. SPEED CONTROL SWITCH TESTS SWITCH POSITION PINS (*RESISTANCE - OHMS) NO PUSH BUTTONS DEPRESSED 13 and 14 (20708) 14 and 15 (20591) ON / OFF 13 and 14 (464) 14 and 15 (133) CANCEL 13 and 14 (896) 14 and 15 (457) DISTANCE (WITH ADAPTIVE SPEED CONTROL ONLY) 13 and 14 (1515) 14 and 15 (899) MODE (WITH ADAPTIVE SPEED CONTROL ONLY) 13 and 14 (2468) 14 and 15 (1518) SET / - (DECEL) 13 and 14 (4088) 14 and 15 (2471) RESUME / + (ACCEL) 13 and 14 (7408) 14 and 15 (4091) *All resistance values are plus or minus 5%.
4. If the switch fails any of the tests, replace the ineffective speed control switch pod as required.

REMOVAL

Scheme 4

Scheme 5

Scheme 6

1. Disconnect and isolate the battery negative cable.
2. Remove the driver airbag from the steering wheel. Refer to «AIR BAG, DRIVER , REMOVAL»(/jeep/grand-cherokee/wk2-2010-2013/remont/airbag/#restraints-service-information) .
3. From the back of the steering wheel (4), remove the two screws (2) that secure the center spoke of the rear cover (1) to the center spoke of the steering wheel spoke front bezel (3).
4. From the face of the steering wheel, remove the four screws (2) that secure the front spoke bezel (4) to the steering wheel armature within the steering wheel hub cavity.
5. Using a trim stick or another suitable wide flat-bladed tool, carefully pry at the parting line between the front spoke bezel and the steering wheel rear cover enough to unsnap the two horizontal members of the bezel from those of the rear cover.
6. Pull the front spoke bezel away from the steering wheel far enough to access and disconnect the steering wheel wire harness connections from the Electronic Vehicle Information Center (EVIC) switch pod (1) and the speed control switch pod (3).
7. From the back of the steering wheel spoke front bezel (4), remove the three screws (2) that secure the speed control switch pod (1) mounting tabs to the bezel.
8. Remove the switch from the bezel.

INSTALLATION

1. Position the speed control switch pod (1) to the back of the steering wheel spoke front bezel (4).
2. Install and tighten the three screws (2) that secure the switch mounting tabs to the bezel. Tighten the screws securely.
3. Position the front spoke bezel close enough to the steering wheel to reconnect the steering wheel wire harness connections to the Electronic Vehicle Information Center (EVIC) switch pod and the speed control switch pod connector receptacles (3).
4. Position the front spoke bezel (4), EVIC switch pod (1) and speed control switch pod (3) as a unit to the steering wheel. Be certain that the steering wheel wire harness is routed between the lower or upper bezel stanchions and the inside circumference of the steering wheel hub cavity so that the wiring will not be pinched when the driver airbag is reinstalled.
5. Use hand pressure to squeeze the horizontal spokes of both the front spoke bezel and the steering wheel rear cover together until all of the snap features are fully engaged.
6. Install and tighten the four screws that secure the stanchions of the front spoke bezel to the steering wheel armature within the steering wheel hub cavity. Tighten the screws securely.
7. From the back of the steering wheel (4), install and tighten the two screws (2) that secure the center spoke of the rear cover (1) to the center spoke of the steering wheel spoke front bezel (3). Tighten the screws securely.
8. Reinstall the driver airbag onto the steering wheel. Refer to «AIR BAG, DRIVER , INSTALLATION»(/jeep/grand-cherokee/wk2-2010-2013/remont/airbag/#restraints-service-information) .
9. Reconnect the battery negative cable.

See also:
• MODULE, ANTI-LOCK BRAKE SYSTEM , DESCRIPTION
• SWITCH, STOP LAMP , DESCRIPTION
• DESCRIPTION
• SENSOR, WHEEL SPEED, FRONT , DESCRIPTION
• COMMUNICATION , DESCRIPTION
• CENTER, ELECTRONIC VEHICLE INFORMATION , DESCRIPTION
• WARNING
• SWITCH, SPEED CONTROL , REMOVAL