Wednesday, April 3, 2019

2019 Cadillac Truck Escalade AWD V8-6.2L Diagnostic Instructions Page 563


Replacement (Tahoe with HP2) ()Driver or Passenger Seat Back Cushion Heater Replacement (without HP2) ()



* Driver or Passenger Seat Cushion Heater Replacement (without HP2) ()Driver or Passenger Seat Cushion Heater Replacement (with HP2)



()



* Control Module References (See: Testing and Inspection/Programming and Relearning) for the HSM replacement, setup, and programming



Rear Seat



DTC B2508 or B2509 (Rear Seat)



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 rear seat heating elements are controlled by a common high current relay internal to the rear heated seat module (RHSM) and on the low side by



individual element control circuits. The RHSM connects the seat heater element supply voltage circuits to a common reference point. This reference



point is biased to approximately 2.5 V. Before the RHSM will allow heated seat operation, it checks to see if the heating element supply voltage



circuits and control circuits are shorted to ground or battery voltage. Once the RHSM verifies that it is not closing to a shorted heating element, it



allows heated seat operation. After which it continues to monitor for a shorted circuit.



Conditions for Running the DTC



The RHSM must be powered.



Conditions for Setting the DTC



B2508 02



Before the heated seats are activated, the RHSM detects a short to ground on the seat heating element supply voltage circuit or control circuit.



B2508 01



Before the heated seats are activated, the RHSM detects a short to battery voltage on the seat heating element supply voltage circuit or control

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