Chevrolet Trax: DTC U0020:Low speed can bus
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 Descriptors
DTC U0020
Low Speed CAN Bus
For symptom byte information, refer to Symptom Byte List .
Circuit/System Description
Devices connected to the GMLAN serial data circuits monitor for serial data
communications during normal
vehicle operation. Operating information and commands are exchanged among the
devices. The devices have
programmed information about what messages are needed to be exchanged on the
serial data circuits. The
messages are also supervised and some periodic messages are used by the receiver
device as an availability
indication of the transmitter device.
Conditions for Running the DTCs
- Supply voltage to the devices is in the normal operating range.
- The vehicle power mode requires serial data communication to occur.
- The DTC U2100 does not have a current status.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter device
availability has not been received
Action Taken When the DTCs Sets
The device uses a default value for the missing parameter.
Conditions for Clearing the DTC
- A current DTC clears when the malfunction is no longer present.
- A history DTC clears when the device ignition cycle counter reaches the
reset threshold, without a repeat
of the malfunction
Circuit/System Verification
Diagnosis of this DTC is accomplished via the symptom or an additional DTC.
Refer to Scan Tool Does Not
Communicate with Low Speed GMLAN Device, or Diagnostic Trouble Code (DTC) List -
Vehicle .
READ NEXT:
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.
Diag
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.
Diag
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.
Diag
SEE MORE:
Removal Procedure
Drain the cooling system. Refer to Cooling System Draining and Filling .
Remove the air cleaner assembly. Refer to Air Cleaner Assembly
Replacement .
Fig. 58: Rear Hose, Hose Retainer And Rear Hose Clamp
Using BO-38185 Hose Clamp Pliers , reposition the heater outlet rear
Do a safety check before
proceeding. See If a Tire Goes
Flat
Remove the wheel cover, if the
vehicle has one, to reach the
wheel bolts.
Turn the wheel wrench
counterclockwise to loosen the
wheel nuts. Do not remove
them yet.
Place the jack at the position
marked with a half c