Service Information

Cruze

DTC P056C

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 P056C 00: Cruise Control Cancel Switch Circuit Malfunction

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+	1	1	1	-
Signal	1	P0564 00	B3794 08, P0567 00, P0568 00	B3794 08
1. Cruise Control Malfunction

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

•	The BCM detects an invalid voltage signal on the cruise control switch signal circuit for greater than 2 s and sends a serial data message to the ECM. The ECM sets these DTCs when the message is received.

•	The ECM runs this diagnostic every 0.05 s.

Action Taken When the DTC Sets

DTC P056C 00 is a type C DTC.

Conditions for Clearing the DTC

DTC P056C 00 is a type C DTC.

Reference Information

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 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

Ignition OFF, disconnect the wiring harness plug at the S70L Steering Wheel Controls Switch - Left.
Ignition ON, test for B+ between the voltage reference circuit and ground.

⇒	If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

Test for B+ between the voltage reference circuit and the signal circuit.

⇒	If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

Ignition OFF, disconnect the X3 harness connector at the K9 Body Control Module.
Test for infinite resistance between the signal circuit terminal 36 and ground.

⇒	If less than the specified value, test the signal circuit for a short to ground.

If all circuits test normal, test or replace the S70L Steering Wheel Controls Switch - Left.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Cruise Control Switch Replacement

•	Control Module References for BCM replacement, setup, and programming