GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0564: Cruise Control Multifunction Switch Circuit

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

B+

1

P0564

1

--

P0564

Cruise Control ON/OFF Switch Signal

1

P0564

1

P0567

P0568

P0564

Cruise Control Resume/Accel. Switch Signal

1

1

1

P0567

--

Cruise Control Set/Coast Switch Signal

1

1

1

P0568

--

1. Cruise Control Malfunction

Circuit/System Description

The cruise control switch is an input to the engine control module (ECM). The ECM monitors the cruise control switch signal circuit in order to detect when a cruise control function switch has been activated. The ECM detects a predetermined voltage signal when a cruise control function switch is applied, with each switch having a different voltage value.

Conditions for Running the DTC

    • The ignition is ON.
    • The cruise switch is ON.

Conditions for Setting the DTC

    • 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 every 0.05 second.

Actions Taken When the DTC Sets

    • The malfunction indicator lamp (MIL) will not illuminate.
    • The cruise control system is disabled.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists.
    • A history DTC will clear after 40 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Cruise Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cruise Control Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Engine ON, while rotating the steering wheel to both steering stops, observe the scan tool Cruise Control Switch parameter while pressing each of the cruise control switches. The parameter should toggle between ON, OFF, Resume, Set, and Cancel as the applicable switch is pressed.

Circuit/System Testing

  1. Ignition OFF, disconnect the X201 harness connector at the turn signal/multifunction switch.
  2. Ignition ON, test for B+ between the B+ circuit terminal A8 and ground.
  3. If less than the specified value, test the circuit for a short to ground or an open/high resistance.
  4. Verify the scan tool Cruise ON/OFF switch parameter displays OFF.
  5. If not the specified value, test the signal circuit terminal B8 for a short to voltage. If the circuit tests normal, replace the ECM.
  6. Install a 3A fused jumper wire between the signal circuit terminal B8 and the B+ circuit terminal A8. Verify the scan tool Cruise ON/OFF Switch parameter displays ON.
  7. If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  8. If all circuits test normal, test or replace the turn signal/multifunction switch.

Component Testing

  1. Disconnect the X201 steering column harness connector.
  2. Cruise control switch ON, measure the resistance between terminal A8 and terminal B8 while individually activating and holding each cruise control function switch and compare the resistance reading to the values in the table below.
  3. If not within the specified resistance range, replace the turn signal/multifunction switch.

Function Switch

Minimum Resistance Value

Maximum Resistance Value

OFF

O.L.

O.L.

ON

8.0k Ohms

8.4k Ohms

Set/Coast

1.3k Ohms

1.7k Ohms

Resume/Accel.

4.2k Ohms

4.6k Ohms

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Turn Signal Multifunction Switch Replacement
    •  Control Module References for ECM replacement, setup, and programming