2010 Cadillac Truck SRX FWD V6-3.0L Page 699

2010 Cadillac Truck SRX FWD V6-3.0L Page 699

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

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

* Relay Replacement (Attached to Wire Harness) (See: Power and Ground Distribution/Power Distribution Relay/Service and Repair/Relay

Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (See: Power and Ground Distribution/Power

Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))

* Windshield Washer With Seal Pump Replacement (See: Sensors and Switches/Sensors and Switches - Wiper and Washer

Systems/Windshield Washer Switch/Service and Repair/Windshield Washer With Seal Pump Replacement)

B3843

DTC B3843

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 Descriptor

DTC B3843 02

- Outside Air Quality Sensor Circuit Short to Ground

DTC B3843 05

- Outside Air Quality Sensor Circuit High Voltage/Open

DTC B3843 08

- Outside Air Quality Sensor Circuit Performance - Signal Invalid

Circuit/System Description

The HVAC control module detects exhaust gas by an air quality sensor. The air quality sensor is a 3-wire sensor with an ignition voltage circuit, a

ground circuit and a signal circuit.

The information is pulse width modulation (PWM) signal generated on the output pin.

The HVAC control module evaluates the information of the air quality sensor and closes the recirculation door while in the automatic mode as soon

as the concentration of pollutants exceeds a preset value.

Conditions for Running the DTC

* Ignition ON.

* The HVAC control module is ON.

Conditions for Setting the DTC

B3843 02

No PWM is detected and the signal is low.

B3843 05

No PWM is detected and the signal is high.

B3843 08

The Sensor sends a 5% PWM signal indicating an internal sensor short circuit or open circuit.

Action Taken When the DTC Sets

The automatic recirculation mode is disabled.