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Tahoe / Yukon Service Manual

Cruise Control Malfunction

Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC B3623 Steering Wheel Controls Distance Sensing Cruise Control Gap Up/Down Signal Circuit DTC B3794 Cruise Control Function Request Circuit DTC P0564 Cruise Control Multifunction Switch Circuit DTC P0565 Cruise Control Switch Circuit DTC P0567 Cruise Control Resume Switch Circuit DTC P0568 Cruise Control Set Switch Circuit DTC P056C Cruise Control Cancel Switch Circuit DTC P0580 Cruise Control Multifunction Switch Circuit Low Voltage DTC P0581 Cruise Control Multifunction Switch Circuit High Voltage DTC P0589 Cruise Control Multifunction Switch 2 Circuit DTC P0592 Cruise Control Multifunction Switch 2 Circuit Low Voltage DTC P0593 Cruise Control Multifunction Switch 2 Circuit High Voltage DTC P155A Cruise Control Switch State Undetermined DTC P155B Cruise Control Set/Coast Switch 2 Circuit DTC P155C Cruise Control Resume/Accelerate Switch 2 Circuit DTC P162C Vehicle Speed Limiting/Warning Switch Circuit Symptom Byte Information: Symptom Byte List Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc e
12V Reference 1 1 — —
Cruise Control Set/Coast/Resume/Accelerate Switch Signal 1, P0580 B3794, P0565 B3794, P0567, B3794, P0564, P155A
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Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc
P0568, P0581
Distance Sensing Cruise Control Gap Up/Down Switch Signal P155A, P155B P155A, P155B 1 —
1. Cruise Control = Malfunction

Typical Scan Tool Data Body Control Module - Scan Tool Parameter

Circuit Cruise Control Switch Status — Parameter Cruise Control Switch 2 — Parameter
12V Reference = Normal Function Inactive Idle
12V Reference = Open Circuit Open/Short to Ground Idle
12V Reference = Short to Ground Undetermined State Undefined
12V Reference = Short to Voltage Inactive Idle
Circuit Cruise Control Switch Status — Parameter Cruise Control Switch 2 — Parameter
Cruise Control Set/Coast/Resume/Accelerate Switch Signal = Normal Function Inactive /Cruise Control On /Set /Resume /Cancel Idle
Cruise Control Set/Coast/Resume/Accelerate Switch Signal = Open Circuit Open/Short to Ground Idle
Cruise Control Set/Coast/Resume/Accelerate Switch Signal = Short to Ground Open/Short to Ground Idle
Cruise Control Set/Coast/Resume/Accelerate Switch Signal = Short to Voltage Short to Battery Idle
Circuit Cruise Control Switch Status — Parameter Cruise Control Switch 2 — Parameter
Distance Sensing Cruise Control Gap Up/Down Switch Signal = Normal Function Inactive Idle /Gap Down
Circuit Cruise Control Switch Status — Parameter Cruise Control Switch 2 — Parameter
Distance Sensing Cruise Control Gap Up/Down Switch Signal = Open Circuit Open/Short to Ground Inactive
Distance Sensing Cruise Control Gap Up/Down Switch Signal = Short to Ground Undetermined State Undefined
Distance Sensing Cruise Control Gap Up/Down Switch Signal = Short to Voltage Inactive Short to Battery

Circuit/System Description For an overview of the component/system, refer to: Cruise Control Description and Operation Conditions for Running the DTC Ignition/Vehicle = On Vehicle Speed. = Greater than 40 km/h (25 MPH) Cruise Control = On Frequency the DTC runs = Continuously — After the running conditions are met — For greater than 5 s Conditions for Setting the DTC B3623 Distance Sensing Cruise Control Follow Gap Set Circuit — Invalid Signal Received B3794, P0564, P0565, P0567, P0568, P056C, P0580, P0581 Cruise Control Switch Circuit — Invalid Signal Received P0589, P0592, P0593, P155B, P155C Cruise Control Multifunction Switch 2 Circuit — Invalid Signal Received P155A Cruise Control Switch State Undetermined P162C Vehicle Speed Limiting/Warning Switch Circuit — Undetermined State Actions Taken When the DTC Sets Cruise Control System Status = Disabled DTCs listed in the DTC Descriptor category = Type C DTC Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type C DTC Diagnostic Aids The cruise control system can be inhibited or disengaged for a number of reasons. These reasons may be a normal function of the vehicle or as a result of action the driver has taken. The cruise control system may also be inhibited or disengaged because of a fault in a vehicle system. The K20 Engine Control Module has a scan tool data list available that can help identify what may have caused a cruise control inhibit or disengage. The scan tool ECM Cruise Control Disable History Data list identifies conditions that will inhibit cruise control. When the cruise control system is inhibited the cruise control system will be prevented from engaging when requested by the driver, or the cruise control system will disengage, if the driver was actively utilizing the system. When attempting to diagnose the system, it is important to discuss with the customer the conditions under which the apparent malfunction occurred. This is critical to help identify those scenarios where the inhibit or disengage is the result of a driver action or normal system response and clarify how the function works. It is also critical to identify when the apparent malfunction occurred when attempting to replicate the condition. The parameters in the scan tool ECM Cruise Control Disable History Data list can be used to help isolate what is causing an inhibit or disengage condition. The scan tool ECM Cruise Control Disable History Data list has parameters that identify the last eight causes of an inhibit and the last eight causes of a disengage. For each Cruise Control Inhibit History and Cruise Control Disengage History parameter, extra information is included in additional parameters: Odometer at First Malfunction, Odometer at Last Malfunction, Diagnostic Status, Malfunction Counter, and Ignition Cycles Since Last Diagnostic Event. The scan tool parameters are a rolling snapshot of the last eight inhibit and disengage reasons, however, if the same condition causes an inhibit or disengage, the reason will not be logged in the next parameter. Instead, the Malfunction Counter parameter will increment and the Odometer at Last Malfunction parameter will update with the most recent odometer value that the condition occurred. When diagnosing an inhibit or disengage concern, especially in the case of an intermittent condition, these parameters are useful in helping determine the cause. Recurring causes will have a larger number in the Malfunction Counter parameter and will likely have a wide variance between the Odometer at First Malfunction and Odometer at Last Malfunction value, indicating the condition has occurred over a period of time driving the vehicle. Reference Information Schematic Reference Cruise Control Schematics Connector End View Reference Master Electrical Component List Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs DTC Type Reference Powertrain Diagnostic Trouble Code (DTC) Type Definitions Scan Tool Reference Control Module References Circuit/System Verification

  1. Ignition » On / Vehicle » In Service Mode
  2. Verify the condition does not exist: Cruise Control System Status = Inhibit by ECM ⇒ Cruise Control System Status = Inhibit by ECM If a condition exists » Repair or replace as necessary ⇓ Cruise Control System Status ≠ Inhibit by ECM
  3. Verify the component works as specified: Cruise Control Switch Assembly
  4. Refer to: Body Control Module - Scan Tool Parameter ⇒ If a condition exists Refer to Circuit/System Testing. ⇓ If no condition exists
  5. Verify that no DTC listed in the DTC Descriptor Category is set. ⇒ If a related DTC is set Refer to Circuit/System Testing. ⇓ If a related DTC is not set
  6. All OK. Circuit/System Testing Cruise Control Switch Signal
  7. Ignition/Vehicle & All vehicle systems » Off
  8. Disconnect the component: K9 Body Control Module
  9. Disconnect the component: Cruise Control Switch Assembly
  10. Ignition » On / Vehicle » In Service Mode
  11. Test for less than 1 V between the test points: 12 V Reference circuit & Ground Cruise Control Switch Signal & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇓ If less than 1 V
  12. Ignition/Vehicle » Off
  13. Test for infinite resistance between the test points: 12 V Reference circuit & Ground Cruise Control Switch Signal & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance
  14. Test for less than 2 Ω between the test points: 12 V Reference circuit @ Component harness & The other end of the circuit @ Control module harness Cruise Control Switch Signal @ Component harness & The other end of the circuit @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇓ If less than 2 Ω
  15. Test or replace the component: Cruise Control Switch Assembly
  16. Operate the vehicle within the Conditions for Running the DTC. Verify the DTC does not set. ⇒ If the DTC sets Replace the component: K9 Body Control Module ⇓ If the DTC is not set
  17. All OK. Distance Sensing Cruise Control Gap Up/Down Switch Signal
  18. Ignition/Vehicle & All vehicle systems » Off
  19. Disconnect the component: K9 Body Control Module
  20. Disconnect the component: Cruise Control Switch Assembly
  21. Ignition » On / Vehicle » In Service Mode
  22. Test for less than 1 V between the test points: 12 V Reference circuit & Ground Distance Sensing Cruise Control Gap Up/Down Switch Signal & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇓ If less than 1 V
  23. Ignition/Vehicle » Off
  24. Test for infinite resistance between the test points: 12 V Reference circuit & Ground Distance Sensing Cruise Control Gap Up/Down Switch Signal & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance
  25. Test for less than 2 Ω between the test points: 12 V Reference circuit @ Component harness & The other end of the circuit @ Control module harness Distance Sensing Cruise Control Gap Up/Down Switch Signal @ Component harness & The other end of the circuit @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇓ If less than 2 Ω
  26. Test or replace the component: Cruise Control Switch Assembly
  27. Operate the vehicle within the Conditions for Running the DTC. Verify the DTC does not set. ⇒ If the DTC sets Replace the component: K9 Body Control Module ⇓ If the DTC is not set
  28. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification For control module replacement, programming, and setup refer to: Control Module References