DTC P056C
Diagnostic Instructions
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
|
|
| |
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. |
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
Schematic Reference
Cruise Control Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Cruise Control Description and Operation
Electrical Information Reference
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
| 1. |
Ignition OFF, disconnect the
harness connector at the S70L Steering Wheel Controls Switch -
Left. |
| 2. |
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. |
| 3. |
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. |
| 4. |
Ignition OFF, disconnect the
X3 harness connector at the K9 Body Control Module. |
| 5. |
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. |
| 6. |
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.
|
