PIE0759B

Subject:
Engineering Information - Malfunction Indicator Lamp (MIL) Illuminated on Driver Information Center (DIC), HVAC Not
Blowing Cold Air and/or HVAC Working Intermittently, DTCs P0534, P1E00 Set
Attention:
Proceed with this EI if the customer has commented about this concern AND the PIE number is listed in the Global
Warranty Management / Investigate History link (GWM/IVH). If the customer has not commented about this condition
or the EI does not show in GWM/IVH, disregard the PIE and proceed with diagnostics found in published service
information. THIS IS NOT A RECALL refer to Service Bulletin 04-00-89-053 for more details on the use of Engineering
Information bulletins.
This EI has been revised to update the Subject, Condition, Correction, and Contact Information. Please discard PIE0759A.
Brand:
Cadillac
Model:
Model Year:
LYRIQ
VIN Breakpoint:
from
to
from
to
2023
2024
–
–
Engine:
Transmission:
–
–
Involved Region or Country
U.S. Dealers ONLY
Condition
Some customers may comment on have one or more of the following conditions:
•
•
•
Malfunction Indicator Lamp illuminated on Driver Information Center (DIC)
HVAC not blowing cold air
HVAC working intermittently
Technicians may find one of the following DTCs set.
•
•
P0534 - Air Conditioning Refrigerant Charge Low
P1E00 - Hybrid/Electric Vehicle Powertrain Control Module 2 Requested Malfunction Indicator Lamp
Illumination
GM Engineering is attempting to determine the root cause of the above condition. Engineering has a need to
gather information on vehicles PRIOR to repair that may exhibit this condition. As a result, this information will
be used to "root cause" the customer's concern and develop/validate a field fix.
Cause
Correction
Important: Service agents must comply with all International, Federal, State, Provincial, and/or Local laws applicable to the activities it performs
under this bulletin, including but not limited to handling, deploying, preparing, classifying, packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict between the procedures set forth in this bulletin and the laws that apply to your dealership, you must
follow those applicable laws.
Important: This engineering information (EI) can only be completed by certified repair facilities who have met all specific training, tool and equipment
requirements pertaining to the vehicle Brand and Model serviced. Repairs must be performed by a technician who has successfully completed the required
training.
If you encounter a vehicle with the above concern, perform the following steps BEFORE contacting one of the engineers listed below.
Note: DO NOT perform a code clear.
Follow the SI procedure for this DTC (P0534). This will involve several steps. Please ensure that you complete the stated tests.
Special notes:
–
It is important to confirm that the refrigerant system is fully charged. While inspecting for proper charge, verify the recovered oil for debris.
–
If a leak is observed/suspected:
•
•
Trace the source of the refrigerant leak using A/C dye and a black light.
If a leak is located take a clear close-up picture of the location on the pipe where the leak was found.
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•
•
–
If the location of the leak was found at the joint, check the torque on the joint.
Please contact the Engineer below (redacted).
If all steps in the SI procedure for P0534 are complete, sensors are functioning and there is no evidence of a refrigerant leak or an undercharged
refrigerant system:
•
Verify that the Passenger Cabin Air Temperature (PCAT) sensor voltage is correct. This can be verified using the GDS tool under HVAC sensor
data.
•
If the PCAT is displaying the correct voltage (converted to an expected temperature), please proceed by contacting Engineering (redacted).
Contact Information
The Contact Information has been redacted.
Please include the following information if leaving a message:
–
Technician name
–
Dealer name and phone number
–
Complete VIN and repair order (R.O) number
On the repair order, document the date and time the call was placed (even if the engineer was not reached).
If engineering is unable to return the call within one hour, proceed with diagnosis and repair based on information found in SI.
Warranty Information
If engineer was contacted or required information was provided, use:
Labor Operation
Description
Labor Time
4488398*
Engineering Information - MIL Illuminated on (DIC), A/C Not Blowing Cold Air
and/or A/C Working Intermittently, DTCs Set
0.6 Hrs.
*This is a unique Labor Operation for bulletin use only.
Version
3
Modified
Released August 28, 2023
Revised October 11, 2023 - Updated Steps 2 and 3 and the Contact Information.
Revised November 16, 2023 - Updated the Subject, Condition, Correction and Contact Information.
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