2010 Cadillac Truck SRX FWD V6-3.0L Page 154

2010 Cadillac Truck SRX FWD V6-3.0L Page 154

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 B048D 01

- Auxiliary Heater Temperature Command Circuit Short to Battery

DTC B048D 06

- Auxiliary Heater Temperature Command Circuit Low Voltage/Open

DTC B048E 00

- Auxiliary Heater System Malfunction

Circuit/System Description

The HVAC control module sends a pulse width modulation (PWM) signal to the electrical auxiliary heater, if the interior temperature is too low

and additional heat is requested. The request signal from the HVAC control module, battery positive, ignition and ground circuits enable the

electrical auxiliary heater to operate. Through the signal circuit the electrical auxiliary heater sends via a PWM signal the current status to the

HVAC control module.

Conditions for Running the DTC

* Ignition ON.

* The HVAC control module is ON.

* The electrical auxiliary heater is ON.

Conditions for Setting the DTC

B048D 01

The voltage at the HVAC control module output to the electrical auxiliary heater is always high.

B048D 06

The voltage at the HVAC control module output to the electrical auxiliary heater is always low or floating.

B048E 00

The feedback signal of the electrical auxiliary heater does not correspond with the requested PWM signal.

Action Taken When the DTC Sets

The electrical auxiliary heater is inoperative.

Conditions for Clearing the DTC

The feedback signal of the electrical auxiliary heater corresponds with the requested PWM signal.

Reference Information

Schematic Reference

HVAC Schematics (See: Heating and Air Conditioning/Diagrams/Electrical Diagrams)

Connector End View Reference

Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)

Description and Operation

Automatic HVAC Description and Operation (See: Heating and Air Conditioning/Description and Operation)

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit

Testing/Circuit Testing)