Chevrolet Trax: Air conditioning compressor malfunction (C67)
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.
Circuit/System Description
The A/C compressor uses a conventional belt driven magnetic clutch to engage
and mechanically turn the
compressor. When the A/C switch is pressed, the HVAC control module sends an A/C
request message to the
ECM via serial data. If specific criteria is met, the ECM then grounds the A/C
compressor clutch relay control
circuit, which will switch the A/C compressor clutch relay. With the relay
contacts closed, battery voltage is
supplied to the permanently grounded A/C compressor clutch. The A/C compressor
clutch will then be
activated.
Diagnostic Aids
The following conditions must be met in order to turn on the A/C compressor:
- Battery voltage is between 9-18 V.
- Engine coolant temperature is less than 124ºC (255ºF).
- Engine speed is greater than 600 RPM.
- Engine speed is less than 5 500 RPM.
- A/C high side pressure is between 269-2 929 kPa (39-425 PSI).
- Throttle position is less than 100%.
- Evaporator temperature is greater than 3ºC (38ºF).
- ECM does not detect excessive torque load.
- ECM does not detect insufficient idle quality.
- The ambient temperature is above 1ºC (34ºF).
- Blower motor must be in any other position than off.
- A/C switch is depressed.
Reference Information
Schematic Reference
HVAC Schematics (Encore), HVAC Schematics (Trax)
Connector End View Reference
WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS -
INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT
CONNECTOR END VIEWS - INDEX - TRAX
Description and Operation
Manual HVAC 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
NOTE: Refer to HVAC System Malfunction (C67) before performing this
procedure
- Ignition ON, press and release the A/C Switch.
- Verify the scan tool HVAC A/C Switch parameter changes between Active
and Inactive.
If the parameter does not change
Replace the A26 HVAC Controls.
If the parameter changes
- Set A/C system to coolest setting with blower ON.
- Press and release the A/C switch several times.
- Verify the scan tool ECM A/C Request Signal parameter changes between
Active and Inactive.
If the parameter does not change
Replace the K33 HVAC Control Module.
If the parameter changes
- Verify the A/C compressor clutch engages when commanding the ECM A/C
Relay output function On
and Off with a scan tool.
If the A/C compressor clutch does not engage
Refer to DTC P0645, P0646, or P0647
If the A/C compressor clutch engages
- All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- HVAC Component Replacement Reference (C67)
- Control Module References for HVAC control module replacement,
programming and setup
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
HVAC Control Module Replacement
When replacing or disconnecting the HVAC control module, it will be necessary
to perform a recalibration
process. When installing or reconnecting the HVAC control modu
SEE MORE:
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
NO
Rear safety belt comfort guides may
provide added safety belt comfort
for older children who have
outgrown booster seats and for
some adults. When installed on a
shoulder belt, the comfort guide
positions the shoulder belt away
from the neck and head.
Safety belt comfort guides are
available throug