Scheme 1
Scheme 2
Diagnostic Code Index
| DTC | Description |
|---|---|
| DTC P0572 or P0573 | DTC P0572 Brake Switch Circuit 1 Low Voltage DTC P0573 Brake Switch Circuit 1 High Voltage |
| DTC P0575 | DTC P0575 Cruise Control Switch Signal Message Counter Incorrect |
| DTC P0703 | DTC P0703 Brake Switch Signal Message Counter Incorrect |
DIAGNOSTIC CODE INDEX
Diagnostic Instructions
- Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
- Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
- «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
Diagnostic Fault Information
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
| Ignition | 1 | 1 | ||
| Signal | 1 | P0564 | B3794 08, P0567, P0568 | B3794 61, P0564 |
| 1. Cruise Control Malfunction | ||||
Circuit/System Description
The cruise control switch is an input to the body control module (BCM). The BCM monitors the cruise control on/off, set/coast, resume/accelerate and cancel switches via the cruise control switch signal circuit in order to detect when the driver has requested to perform a cruise control function. The BCM detects a specific voltage signal on the cruise control switch signal circuit when a switch is applied. The engine control module (ECM) receives the requested cruise control switch function from the BCM via a serial data message.
Conditions for Running the DTC
- The cruise switch is ON.
- The ignition is ON.
Conditions for Setting the DTC
B3794 08
The BCM detects an invalid voltage signal on the cruise control switch signal circuit for 1 second.
B3794 61
Stuck switch for either Resume/Accel or Set/Coast button for 60 seconds.
P0564, P0565, P0567, P0568, P056C
- The BCM detects an invalid voltage signal on the cruise control switch signal circuit for greater than 2 seconds and sends a serial data message to the ECM. The ECM sets these DTCs when the message is received.
- The ECM runs this diagnostic continuously.
P0580, P0581
- The ECM detects an invalid voltage signal on the cruise control switch signal circuit.
- The above condition is present for greater than 2 seconds.
- The ECM runs this diagnostic continuously.
P155A
The ECM is unable to determine the state of the cruise control switch.
P162C
The ECM is unable to determine the state of the vehicle speed limiting switch.
Actions Taken When the DTC Sets
B3794
- The malfunction indicator lamp (MIL) will not illuminate.
- The cruise control system is disabled.
P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A, P162C
DTCs P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A and P162C are type C DTCs
Conditions for Clearing the DTC
B3794
- The condition responsible for setting the DTC no longer exists.
- A history DTC will clear after 40 malfunction-free ignition cycles have occurred.
P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A, P162C
DTCs P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A and P162C are type C DTCs.
Reference Information
Schematic Reference
Connector End View Reference
WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX
Description and Operation
Electrical Information Reference
- «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
- «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
- «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
- «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON.
- Verify the scan tool ECM Cruise Control Switch Status parameter changes between Off and On, Resume and Set when switching between each position on the cruise control switch. If the parameter does not change Refer to Circuit/System Testing. If the parameter changes
- All OK.
Circuit/System Testing
Note. An open ignition circuit or fuse before the control module will cause communication DTCs or power mode mismatch DTCs to set against or in the control module. This failure mode will be diagnosed in the no communications diagnostic procedure or power mode mismatch. This test assumes the ignition circuit has a driver that will open under a high current condition before the fuse opens. The driver can open under normal conditions such as battery run down protection or a retained accessory power mode.
- Ignition OFF, disconnect the harness connector at the S70L Steering Wheel Controls Switch-Left, ignition ON.
- Verify a test lamp illuminates between the ignition circuit terminal 1 and ground. If the test lamp does not illuminate Ignition OFF, disconnect the harness connector at the K9 Body Control Module. Test for greater than 100 ohms between the ignition circuit and ground. If 100 ohms or less, repair the short to ground on the circuit. If greater than 100 ohms Test for less than 2 ohms in the ignition circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, test or replace the K9 Body Control Module. If the test lamp illuminates
- Verify the scan tool ECM Cruise Control Switch Status parameter is Off. If not Off Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 3 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If Off
- Install a 3 A fused jumper wire between the signal circuit terminal 3 and the ignition circuit terminal 1.
- Verify the scan tool ECM Cruise Control parameter is Disabled. If not Error Ignition OFF, disconnect the harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 9 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Error
- Test or replace the S70L Steering Wheel Controls Switch-Left.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for BCM replacement, programming and setup.
- Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
- Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
- «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
| Stop Lamp Switch Signal | C0297 02, P0572 | P0572 | P0573 | P0572, P0573 |
The stop lamp switch signal circuit is a B+ input from the body control module (BCM) to the engine control module (ECM). The ECM monitors the stop lamp switch circuit to detect when the brake pedal has been applied. The BCM monitors the brake pedal position sensor to determine when the brake pedal is applied. When the brake pedal is applied, the BCM supplies B+ on the stop lamp switch signal circuit and also sends a serial data message to the ECM indicating that the brake pedal has been applied.
- The engine is running.
- Battery voltage is greater than 11.5 V.
- Brakes applied.
P0572
This DTC will set when the ECM detects a short to ground or an open on the discrete brake signal circuit when the serial data message from the BCM indicates the brakes are applied. This diagnostic will run when the serial data message and the voltage signal on the brake switch signal circuit do not match for 8 out 10 times, and the condition is present for greater than 2 s.
P0573
This DTC will set when the ECM detects a short to voltage on the discrete brake signal circuit when the serial data message from the BCM indicates the brakes are not applied. This diagnostic will run when the serial data message and the voltage signal on the brake switch signal circuit do not match for 8 out 10 times, and the condition is present for greater than 2 s.
- The malfunction indicator lamp (MIL) will not illuminate.
- The cruise control system is disabled.
- The condition responsible for setting the DTC no longer exists.
- A history DTC will clear after 40 malfunction-free ignition cycles have occurred.
Schematic Reference
Connector End View Reference
WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX
Description and Operation
Electrical Information Reference
- «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
- «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
- «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
- «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
Scan Tool Reference
Control Module References for scan tool information
- Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module, ignition ON.
- Connect a test lamp between the signal circuit terminal 57 and ground.
- Verify the test lamp turns ON and OFF when pressing and releasing the brake pedal. If the test lamp is always OFF Ignition OFF, disconnect the harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit and ground. If not infinite resistance, repair the short to ground on the circuit. If infinite resistance. Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V replace the K9 Body Control Module. If the test lamp turns ON and OFF
- Replace the K20 Engine Control Module.
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for BCM or ECM replacement, programming, and setup.
- Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
- Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
- «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
When a cruise control function switch is activated, the body control module (BCM) detects a predetermined voltage. The BCM sends a serial data message to the engine control module (ECM) indicating the function that has been requested.
- The ignition is ON.
- The vehicle speed is greater than 40 km/h (25 MPH) and the cruise control is engaged.
- The ECM receives an invalid cruise control switch status serial data message from the BCM.
- This diagnostic runs continuously.
DTC P0575 is a type C DTC.
DTC P0575 is a type C DTC.
Schematic Reference
Connector End View Reference
WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX
Description and Operation
Electrical Information Reference
- «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
- «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
- «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
- «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV) , Powertrain Diagnostic Trouble Code (DTC) Type Definitions (2H0)
Scan Tool Reference
Control Module References for scan tool information
- Ignition ON.
- Verify that no DTCs are set, except DTC P0575. If any other DTC is set, except DTC P0575 Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If only DTC P0575 is set
- Replace the K9 Body Control Module.
- Verify DTC P0575 does not set when operating the vehicle within the Conditions for Running the DTC. If the DTC sets Replace the K20 Engine Control Module. If the DTC does not set
- All OK.
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for BCM or ECM replacement, programming, and setup.
- Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
- Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
- «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
The body control module (BCM) monitors the brake pedal position sensor. When the brake pedal is applied, the BCM detects a predetermined voltage signal. The BCM sends a serial data message to the engine control module (ECM) indicating the status of the stop lamps.
The engine is ON.
- The ECM receives an invalid brake pedal status serial data message from the BCM.
- This diagnostic runs continuously.
- The malfunction indicator lamp (MIL) will not illuminate.
- The cruise control system is disabled.
- The condition responsible for setting the DTC no longer exists.
- A history DTC will clear after 40 malfunction-free ignition cycles have occurred.
Schematic Reference
Connector End View Reference
WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX
Description and Operation
Electrical Information Reference
- «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
- «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
- «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
- «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
Scan Tool Reference
Control Module References for scan tool information
- Ignition ON.
- Verify that no DTCs are set, except DTC P0703. If any other DTC is set, except DTC P0703 Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If only DTC P0703 is set
- Replace the K9 Body Control Module.
- Verify DTC P0703 does not set when operating the vehicle within the conditions for running the DTC. If the DTC sets Replace the K20 Engine Control Module. If the DTC does not set
- All OK.
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for BCM or ECM replacement, programming, and setup.
Symptoms - Cruise Control
Note. The following steps must be completed before using the symptom tables.
- Before using the symptom diagnostic table, perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) in order to verify the following conditions: There are no DTCs set. The module can communicate via the serial data.
- Review the system operation in order to understand the system functions. Refer to «Cruise Control Description and Operation»(/buick/encore/i-2012-2016/remont/cruise-control-systems/#cruise-control-system) .
Visual/Physical Inspection
- Inspect for aftermarket devices which can affect the operation of the Cruise Control System. Refer to «Checking Aftermarket Accessories»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
- Inspect the accessible system components or the visible system components for obvious damage or for obvious conditions which can cause the symptom.
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom
- «Cruise Control Malfunction - DTC B3794, P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A-P155C, or P162C»(/buick/encore/i-2012-2016/remont/cruise-control-systems/#cruise-control-system)
- «Cruise Control Indicator Malfunction»(/buick/encore/i-2012-2016/remont/cruise-control-systems/#cruise-control-system)
- Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
- Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
- «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
The instrument cluster illuminates the cruise control engaged indicator based on serial data messages received from the engine control module (ECM). The indicator is commanded ON when the cruise control system is controlling vehicle speed, and turned OFF with the system disengaged.
Schematic Reference
Connector End View Reference
WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX
Description and Operation
Electrical Information Reference
- «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
- «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
- «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
- «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
Scan Tool Reference
Control Module References for scan tool information
- Ignition ON.
- Verify the cruise control indicator turns ON and OFF when commanding the All Indicators ON and OFF with a scan tool. If the indicator does not turn ON and OFF Replace the P16 Instrument Cluster. If the indicator turns ON and OFF
- All OK.
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for instrument cluster replacement, programming and setup.
Scheme 3
| Callout | Component Name |
|---|---|
| Preliminary Procedure Remove the steering wheel airbag. Refer to Steering Wheel Airbag Replacement (Buick) , Steering Wheel Airbag Replacement (Chevrolet) . | |
| 1 | Steering Wheel Bezel Assembly Procedure Disconnect the electrical connectors. Use the appropriate tool to gently release the bezel assembly from the steering wheel. |
| 2 | Cruise Control Switch Fasteners (Qty: 2) CAUTION: Refer to Fastener Caution . |
| 3 | Cruise Control Switch |
| CAUTION |
|---|
| Refer to Fastener Caution . |
Cruise Control Switch Replacement
Scheme 4
| Callout | Component Name |
|---|---|
| HW | Hard-Wired |
| HW | Hard-Wired |
| DD | Serial Data - GMLAN High Speed |
| K20 | K20 Engine Control Module |
| S70L | S70L Steering Wheel Controls Switch - Left |
| P16 | P16 Instrument Cluster |
| K9 | K9 Body Control Module |
Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions at speeds above 40 km/h (25 mph). Steep grades may cause variations in the selected vehicle speeds.
The following are the main components of the Cruise Control System
- The accelerator pedal
- The brake pedal position (BPP) sensor
- The body control module (BCM)
- The cruise on/off switch
- The cruise control cancel switch
- The + RES switch (equivalent to resume/accel switch)
- The - SET switch (equivalent to set/coast switch)
- The engine control module (ECM)
- The throttle actuator control (TAC) motor (gasoline engines only)
- The vehicle speed sensor
The body control module (BCM) monitors the signal circuit of the cruise control switches, which are located on the steering wheel. The BCM relays the cruise control switch status to the engine control module (ECM) via the serial data circuit. The ECM uses the status of the cruise control switch to determine when to capture and maintain the vehicle speed. The ECM monitors the vehicle speed signal circuit in order to determine the desired vehicle speed.
Voltage is supplied to the cruise control switch via the steering wheel control switch reference voltage circuit supplied by the BCM. The cruise control function switches are arranged in a resistive ladder design, with each cruise control function switch having a different resistance value. The BCM detects a specific voltage value that is associated with the cruise control function switch being activated. The BCM sends a serial data message to the ECM indicating that the on/off switch is active. Similarly, when the normally open + RES switch or the normally open - SET switch are pressed, the switch closes and the BCM detects the predetermined voltage signal on the cruise control resume/accel and set/coast switch signal circuit. The BCM sends a serial data message to the ECM indicating that the + RES switch or the - SET switch is active.
Cruise Control Engaged
The Cruise Control System will engage and adjust vehicle speeds, based on the activation of the following cruise control switches, which are located on the steering wheel
- On/Off
- + RES
- SET
To engage the Cruise Control System, ensure that the vehicle speed is above 40.2 km/h (25 mph), turn the cruise On/Off switch ON and momentarily press the - SET switch. The ECM will engage the Cruise Control System and record the vehicle speed. The ECM sends a serial data message to the instrument panel cluster (IPC) in order to illuminate the Cruise Engaged indicator in the IPC. Refer to the vehicle owner's manual for the location and operation of the cruise control On/Off indicators and driver information center (DIC) messages.
Pressing the accelerator pedal while the Cruise Control System is engaged, allows the driver to override the Cruise Control System in order to accelerate the vehicle beyond the current set vehicle speed. When the accelerator pedal is released, the vehicle will decelerate and resume the current set vehicle speed.
The driver can also override the current set vehicle speed via the - SET switch and the + RES switch. When the Cruise Control System is engaged, pressing and holding the - SET switch will allow the vehicle to decelerate from the current set vehicle speed without deactivating the Cruise Control System. When the - SET switch is released, the ECM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the Cruise Control System is engaged, momentarily pressing the - SET switch will allow the vehicle to decelerate at a vehicle specific calibratable increment, commonly 1.6 km/h (1 mph), each time that the - SET is momentarily pressed, with a minimum vehicle speed of 38 km/h (24 mph). Refer to the vehicle Owner's Manual for more information.
Pressing and holding the + RES switch, when the Cruise Control System is engaged, will allow the vehicle to accelerate to a greater vehicle speed than the current set vehicle speed. When the + RES switch is released, the ECM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the Cruise Control System is engaged, momentarily pressing the + RES switch will allow the vehicle to accelerate at a vehicle specific calibratable increment, commonly 1.6 km/h (1 mph), each time that the + RES switch is momentarily pressed. Momentarily activating the + RES switch will recall the previous vehicle speed, after the cruise control system has been disengaged by pressing the brake pedal, or CANCEL switch. Refer to the vehicle Owner's Manual for more information.
Cruise Control Disengaged
The engine control module (ECM) disengages the cruise control operation based on the signals from the following switches
- The brake pedal position (BPP) sensor
- The On/Off switch
- The cruise control cancel switch
The Cruise Control System will disengage when the brake pedal is applied. The body control module (BCM) monitors the BPP sensor via the BPP sensor signal circuit as the voltage signal increases while the pedal is further applied. The ECM monitors the BPP signal through a discrete input and a serial data message signal from the BCM indicating the brake status. When either signal indicates the brake pedal is applied, the ECM will disengage the cruise control system.
The Cruise Control System will also disengage when the cruise control on/off switch is switched OFF, or the cruise control cancel switch is activated. The body control module (BCM) determines when the cruise control cancel switch is activated. When the normally open cancel switch is closed, the BCM detects the predetermined voltage signal on the cruise control function switch circuit. The vehicle speed stored in the memory of the engine control module will be erased when the cruise control On/Off switch is turned OFF, or the ignition switch is turned OFF. The BCM sends a serial data message to the ECM in order to disengage the cruise control system. When the Cruise Control System has been disengaged, the ECM sends a serial message to the instrument panel cluster (IPC) in order to turn OFF the Cruise Engaged indicator.
Every time the Cruise Control System is disengaged, the ECM will keep track of the reason for system disengagement. The last 8 disengagement reasons will be recorded within the ECM memory. The scan tool will display the last 8 Cruise Disengage History parameters, in which one out of approximately 50 possible reasons will be displayed in each of these 8 parameters. For the disengagement reason to be displayed within the scan tool parameter the Cruise Control System is active and disengagement is requested.
When engagement of the system is requested but an engagement inhibit is present, the most recent inhibit reason is recorded in the ECM history. The scan tool will display the most recent inhibit reason, in which one out of approximately 50 possible reasons will be displayed.
Cruise Control Inhibited
The engine control module (ECM) inhibits the cruise control operation when any of the following conditions exist
- The ECM has not detected a brake pedal activation from the body control module (BCM) this ignition cycle.
- A Cruise Control System DTC has been set.
- The vehicle speed is less than 38.6 km/h (24 mph).
- The vehicle speed is too high.
- The vehicle is in PARK, REVERSE, NEUTRAL, or 1st gear.
- The engine RPM is low.
- The engine RPM is high.
- The system voltage is not between 9 volts and 16 volts.
- The Antilock Brake System (ABS)/Traction Control System (TCS) is active for more than a calibratable time (typically 0.3 to 0.7 seconds).
Cruise Control Inhibit Reasons
This is a general list of inhibit reasons. Not every inhibit reason is applicable to all vehicles. Refer to the scan tool inhibit reason list for the last 8 reasons that have been recorded during the current ignition cycle.
| Scan Tool Name | Description | Long Description |
|---|---|---|
| ACC BRAKE INOP | Adaptive Cruise Control Automatic Braking Failed | Adaptive Cruise Control Automatic Braking Inoperative |
| ACC DATA | Serial data fault for Adaptive Cruise Control Throttle Control and Brake Control signals sent by Adaptive Cruise Control module | Adaptive Cruise Control Module serial data fault is active or communication has been lost between ACC module and ECM. |
| ACC INHIBIT | Adaptive Cruise Control Inhibited | Adaptive Cruise Control Inhibited |
| ACC OPTION | Adaptive Cruise Control option mismatch | Cruise control type (adaptive cruise or conventional cruise) mismatched between ECM and BCM. |
| ACCEL RATE | High acceleration | Vehicle acceleration rate is too high. |
| Accel Time | Rate Limiting Fault | Cruise torque request rate limiting active too long |
| APP OVERRIDE | Pedal greater than cruise (override) | Driver has overridden cruise control set speed with accelerator pedal for greater than an allowable time. |
| Auto Brk Data | Automatic Braking Engine Torque Request Signal Communication Malfunction | ECM to EBCM serial data fault is active or communication has been lost between ECM and EBCM. |
| AXLE RANGE | Rear Axle Low | Rear axle in low range |
| BPP DATA | DTC P0703 active or maximum time elapsed without receiving valid Brake Pedal Position signal. | Serial data fault is active or communication has been lost with module sending brake pedal apply state |
| BPP DTC | Brake Pedal Position signal invalid | Brake Pedal Apply Circuit fault has been detected. |
| BPP Not Learned | Brake Apply Sensor Home Position Not Learned | Brake Pedal Position Sensor Released Position Not Learned. |
| BRAKE | Brake pedal apply | Brake Pedal was applied. |
| Brk Ped Press | Brake Pedal Driver Applied Pressure Detected | A Brake Pedal Apply has been detected based on brake pedal pressure as measured by the EBCM. |
| Calc Eng Torque | Calculated Torque | Engine torque calculation is incorrect. |
| CANCEL | Cancel switch active | Cancel Switch was depressed. |
| CLUTCH | Clutch switch active | Clutch Pedal was applied. |
| COAST DISENGAGE | Coast disengage | Cruise control is in coast mode with the Set/Coast switch depressed and is requesting no throttle |
| COAST SPEED LOW | Coast below low speed inhibit | Set / Coast switch was depressed. Vehicle slowed below minimum cruise operating speed. |
| Cruise Brk Inop | Brake System Malfunction | EBCM has detected a failure that does not allow automatic braking to be performed. |
| CRUISE S/W | Sequence of completion checks | Cruise control software execution error has occurred. |
| CRUISE SW DATA | Serial data fault (Cruise switch serial communication fault) | Cruise switch serial data fault is active or communication has been lost with module sending cruise switch states |
| CRUISE SW. OFF | On/Off switch in Off state | Cruise On/Off switch turned Off |
| DECEL RATE | High deceleration | Vehicle deceleration rate is too high. |
| DLC OVERRIDE | ALDL | Scan Tool plugged into ALDL connector |
| DTC SET | Malfunction in PCM/ECM (DTC active) | DTC is active or in history that inhibits cruise control operation. |
| D WHL SPD HI | Driven Whl Spd Greater (wheel slip detection) | Driven wheel speed greater than Non Driven wheel speed (slip detection) |
| D WHL SPD LOW | Un-driven Whl speed Greater | Non Driven wheel speed greater than driven wheel speed |
| ECM INHIBIT | PCM/ECM inhibit (RAM corruption) | ECM internal communication error |
| ECM RESET | ECM Running Reset | ECM Running Reset occurred |
| ECT OVERTEMP | Engine metal overtemp active | Engine over temperature. Overheated. |
| ENG RUN TIME | Engine run time not elapsed | Engine has not been running long enough, typically five seconds. |
| ENGINE SPEED | Engine speed too low or too high | Engine RPM too low (near stall) or too high (near engine RPM fuel shutoff). |
| FIRST GEAR | 1st Gear | Transmission is engaged in 1st gear |
| HIGH SPEED | Vehicle speed exceeds high speed threshold | Vehicle speed has exceeded maximum cruise operating speed |
| HIGH VOLTAGE | Voltage above high voltage threshold | Ignition Voltage High at ECM (typically 18 volts) |
| ILLEGAL MODE | Illegal cruise mode | Cruise control mode is incorrect based on switch states. |
| LOST FWD GEAR | Transmission in neutral. Reverse or park | Gear selector not in forward gear |
| LOW SPEED | Vehicle speed drops below low speed threshold | Vehicle speed dropped below the cruise control minimum operating speed. May be due to hilly terrain and low vehicle speed. Manual transmission gear selection and engine torque may contribute to this disengagement reason. |
| LOW VOLTAGE | Voltage below low voltage threshold | Ignition Voltage Low at ECM (typically 9 volts) |
| MEMORY DTC | Memory Failure | Control module memory failure detected. |
| MPH LIMIT | MPH Limited Fuel (Vehicle overspeed fuel cut-off active) | Vehicle overspeed protection active with fuel cut off active |
| M/T Gear Changed | Manual transmission out of gear with no clutch pedal apply | Manual transmission shifted to Neutral without clutch pedal being applied. |
| NONE | None | This disengagement reason may be displayed after a dead battery repair or module replacement. |
| OVER SET SPEED | Over schedule | Vehicle speed has exceeded driver selected set speed by more than an allowable amount. This may occur while driving down a significant grade or driver overriding cruise while performing a passing maneuver. |
| PARK BRAKE | Park Brake Switch signal Active | Parking Brake Applied |
| PEDAL INITIALIZE | Brake before cruise | The brake pedal has not been seen as applied prior to driver request to engage cruise with set switch. A brake pedal apply must be seen before allowing cruise engagement during each key cycle. On a vehicle equipped with a manual transmission, a clutch pedal apply may satisfy the brake pedal apply criteria. |
| PTO ACTIVE | Power Take Off Active | Power Take Off is active. |
| Ram DTC | Processor Integrity Fault (Ram corruption) | ECM software error has occurred |
| RPM LIMIT | Injectors Disabled (Engine overspeed fuel cut-off active) | Engine RPM limiter active with fuel cut off active. |
| S/C ON SPEED HI | Over schedule tap-down | Set/Coast switch selected, vehicle speed is above set speed and does not decrease. May be due to traveling down hill |
| SIMUL S/C-R/A | SET and RESUME switches simultaneously active | Set/Coast and Resume Accelerate switches pressed simultaneously |
| SL/W Sys On | Speed Limiter / Warning On/Off switch turned on | Driver has turned on the Speed Limiter/Warning on/off switch. Cruise is disabled / inhibited and cruise on/off switch will be set to OFF. |
| SW. INVALID | Analog cruise switch input out of range | Cruise switch voltage signal in invalid range |
| TAC INHIBIT | ETC prevents cruise operation | Electronic Throttle Control has detected a failure in the throttle control hardware |
| TCS | Traction control active | Traction Control was Active |
| TRANS DTC | Trans Gear Fault | Transmission DTC is active or in history that inhibits cruise control operation |
| UNDER SET SPEED | Under schedule | Vehicle speed is below cruise control set speed by more than an allowable amount |
| VSES | Vehicle stability active | Vehicle Stability Control was active |
| 4WD Low | 4WD Low | Transfer case in low range |
See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Diagnostic Trouble Code (DTC) List - Vehicle
• Checking Aftermarket Accessories
• Steering Wheel Airbag Replacement (Buick)
• Fastener Caution
• DTC P0572 or P0573