ADT HVAC & Comfort Electronics 3

Question 1

An Audi A6 C8 with heat pump system stores fault code B10DB00 'Refrigerant circuit — insufficient heating capacity.' The outside temperature is -5°C. What is the FIRST component to inspect?

Accepted Answer

Reversing valve (4-way valve) operation and solenoid resistance

Answer

The heat pump's reversing valve switches refrigerant flow direction for heating mode; a sticking or failed valve will prevent the system from building adequate heat pump capacity.

Question 2

Which Audi scan tool function allows a technician to manually command individual HVAC flap actuators to their end positions for mechanical binding diagnosis?

Accepted Answer

Output test (Actuator diagnosis)

Answer

The Output Test function in VCDS/ODIS allows each blend door and mode door actuator to be individually driven to its stop positions to verify mechanical freedom and motor function.

Question 3

On an Audi Q5 with automatic recirculation, the system repeatedly switches to recirculation even in clean air conditions. The cabin air quality sensor has been replaced. What should be checked NEXT?

Accepted Answer

LIN bus wiring continuity between sensor and HVAC module

Answer

If the replacement sensor still causes erroneous recirculation, a wiring or LIN bus communication fault between the sensor and module can produce false high-pollutant frames triggering recirculation.

Question 4

An Audi technician uses ODIS to perform a refrigerant quantity check. The system requires 650g of R-1234yf. After recovery, the machine reports only 480g recovered. What does this MOST likely indicate?

Accepted Answer

A leak exists in the system resulting in 170g loss

Answer

A recovery weight of 480g versus the specification of 650g indicates approximately 170g of refrigerant has leaked from the system, requiring a leak test before recharging.

Question 5

The Audi auxiliary parking heater (Webasto/Eberspächer) uses which fuel source on diesel-engined Audi vehicles?

Accepted Answer

Diesel fuel tapped from the vehicle's main fuel tank

Answer

Audi's diesel parking heater draws diesel fuel directly from the main fuel tank via a metering pump to combust and heat the coolant circuit.

(ADT) Audi Diagnostic Technician Practice Test

(ADT) Audi Diagnostic Technician Practice Test

ADT HVAC & Comfort Electronics 3