Dtc P0571 - Suzuki XL7 2007 Service Manual

10A-12 Cruise Control System:
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector C1
at the BCM.
2. Ignition ON, verify that a test lamp does not
illuminate between the steering wheel control supply
voltage circuit terminal 17 and ground.
➢ If the test lamp illuminates, test the steering wheel
control supply voltage circuit for a short to voltage.
3. Ignition OFF, disconnect the harness connector C3
at the BCM.
4. Ignition ON, verify that a test lamp does not
illuminate between the cruise control indicator
dimming signal circuit terminal 22 and ground.
➢ If the test lamp illuminates, test the cruise control
indicator dimming signal circuit for a short to
voltage. If the circuit tests normal, replace the
steering wheel controls switch assembly - left.
5. If all circuits test normal, replace the BCM.
Repair Instructions
Perform the "Diagnostic Repair Verification - Vehicle
Diagnostic Information: ".
• "Steering Wheel Control Switch Assembly
Replacement: "
• "Control Module References: " for BCM replacement,
setup, and programming

DTC P0571

Diagnostic Instructions
• Perform the "Diagnostic System Check - Vehicle
Diagnostic Information: " prior to using this diagnostic
procedure.
• Review "Strategy Based Diagnosis: " for an overview
of the diagnostic approach.
• "Diagnostic Procedure Instructions - Vehicle
Diagnostic Information: " provides an overview of
each diagnostic category.
DTC Descriptor
DTC P0571 00: Cruise Control Brake Switch Circuit
Circuit/System Description
The stop lamp switch signal circuit is a direct hardwire
input to the engine control module (ECM) from the body
control module (BCM). The ECM monitors the stop lamp
switch signal circuit in order to detect when the brake
pedal has been applied. When the brake pedal is
pressed, the BCM sends a serial data message to the
ECM indicating that the brake pedal has been applied.
The BCM also sends a high voltage signal on the stop
lamp switch signal circuit to the ECM. This DTC will set if
the serial data message and the voltage signal on the
stop lamp switch signal circuit do not match.
Conditions for Running the DTC
• The engine speed is greater than 700 RPM.
• The traction control system or the antilock brake
system are not active and have not failed.
Conditions for Setting the DTC
• The ECM detects that there is a 8.3 km/h (5.1 mph) or
greater decrease in vehicle speed within 1 second.
• The ECM detects that the class 2 serial data message
and the voltage signal on the stop lamp switch signal
circuit do not match for 10 consecutive times that this
diagnostic is run.
• The above condition is present for greater than 2
seconds.
Action Taken When the DTC Sets
• The cruise control system is disabled.
• The ECM stores the DTC information into memory
when the diagnostic runs and fails.
• The malfunction indicator lamp (MIL) will not
illuminate.
• The ECM records the operating conditions at the time
the diagnostic fails. The ECM stores this information
in the Failure Records.
Conditions for Clearing the DTC
• A last test failed, or the current DTC, clears when the
diagnostic runs and does not fail.
• A history DTC clears after 40 consecutive warm-up
cycles, if failures are not reported by this or any other
emission related diagnostic.
Reference Information
Schematic Reference
"Cruise Control Schematics"
Connector End View Reference
"Cruise Control 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
• "Scan Tool Data List - Cruise Control"
• "Scan Tool Data Definitions (Disengage History) -
Cruise Control"
Circuit/System Verification
In order to avoid a misdiagnosis, inspect for proper
operation of the stop lamps. Refer to "Exterior Lighting
Systems Description and Operation: " in Lighting
Systems.