2010 Cadillac CTS Sedan AWD V6-3.6L Page 498
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Driver or Passenger Seat Back Cushion Heater Replacement (KA1) (See: Body and Frame/Seats/Seat Temperature Element/Service and
Repair/Driver or Passenger Seat Back Cushion Heater Replacement (KA1))
* Driver Seat Cushion Heater Replacement (KA1) (See: Body and Frame/Seats/Service and Repair/Driver Seat Cushion Heater Replacement
(KA1))
* Passenger Seat Cushion Heater Replacement (KA1) (See: Body and Frame/Seats/Service and Repair/Passenger Seat Cushion Heater
Replacement (KA1))
* Control Module References (See: Testing and Inspection/Programming and Relearning) for MSM replacement, setup, and programming
B2509
DTC B2508 or B2509
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC B2508 01
- Seat Heater Relay Circuit Short to Battery
DTC B2508 02
- Seat Heater Relay Circuit Short to Ground
Diagnostic Fault Information
Circuit/System Description
The driver and passenger seat heating elements are controlled by a common high current relay internal to the memory seat module (MSM) and by
individual low side element control circuits. The MSM connects the heated seat heater element supply voltage circuits for both seats to a common
reference point. This reference point is biased to approximately 2.5 V. Before the MSM will allow heated seat operation, it checks to see if this
reference voltage is shorted to ground or voltage. Once the module verifies that it is not closing to a shorted heating element, it allows for heated
seat operation. The module will then continue to monitor the heating elements for a shorted circuit.
Conditions for Running the DTC
The MSM must be powered.
Conditions for Setting the DTC
