Audi TT Vehicle Systems and Diagnostics 2 — Questions and Answers
Question 1: What type of all-wheel-drive coupling does the transverse-engine Audi TT quattro use to send torque to the rear axle?
- Torsen center differential
- Haldex electro-hydraulic multi-plate clutch (Correct answer)
- Viscous coupling
- Crown-gear center differential
Correct answer: Haldex electro-hydraulic multi-plate clutch
The TT is built on a transverse platform, so its quattro system uses a Haldex multi-plate clutch at the rear axle instead of a Torsen or crown-gear center differential.
Question 2: What does Audi magnetic ride on the TT use to change damping force?
- Air springs with variable pressure
- Electronically switched valves in hydraulic dampers
- Magnetorheological fluid whose viscosity changes in a magnetic field (Correct answer)
- Hydraulic anti-roll bar actuators
Correct answer: Magnetorheological fluid whose viscosity changes in a magnetic field
Magnetic ride dampers hold fluid with magnetic particles that line up when a coil is energized, which changes damping almost instantly.
Question 3: Which dealer-level diagnostic software does Audi use to diagnose and program control modules in the TT?
- ODIS (Offboard Diagnostic Information System) (Correct answer)
- GDS2
- Techstream
- ISTA
Correct answer: ODIS (Offboard Diagnostic Information System)
ODIS is the VW Group's official diagnostic and flashing software used in Audi dealerships.
Question 4: A third-generation (8S) TT shows P0300 with no single-cylinder misfire code. What does this code mean?
- Cylinder 3 misfire detected
- Crankshaft position sensor circuit failure
- Catalyst efficiency below threshold
- Random or multiple cylinder misfire detected (Correct answer)
Correct answer: Random or multiple cylinder misfire detected
P0300 means the ECU has detected misfires that it can't pin to one specific cylinder.
Question 5: What does a failed PCV/oil separator valve typically cause on a TT with the EA888 2.0 TFSI?
- Low coolant temperature readings
- A whistling noise, lean fuel trim codes, and higher oil consumption (Correct answer)
- Transmission slipping in 2nd gear
- Intermittent airbag warning light
Correct answer: A whistling noise, lean fuel trim codes, and higher oil consumption
A torn PCV diaphragm lets in unmetered air, which causes lean codes like P0171, a whistle, and oil getting pulled into the intake.
Question 6: Why are early direct-injection-only 2.0 TFSI TT engines prone to carbon buildup on the intake valves?
- Fuel never washes over the back of the intake valves (Correct answer)
- The exhaust valves run too cool
- The turbocharger pushes oil into the cylinders
- The EGR valve is permanently open
Correct answer: Fuel never washes over the back of the intake valves
With direct injection, fuel sprays straight into the cylinder, so nothing cleans the oil-vapor deposits off the intake valves.
Question 7: On a 3rd-gen TT with an electronic parking brake, what must you do before replacing the rear brake pads?
- Disconnect the battery for 30 minutes
- Pump the brake pedal with the engine running
- Put the EPB into service/maintenance mode with a scan tool to retract the caliper motors (Correct answer)
- Remove the ABS fuse
Correct answer: Put the EPB into service/maintenance mode with a scan tool to retract the caliper motors
The EPB motors must be retracted electronically in service mode, or you can damage the caliper actuators.
Audi TT Vehicle Systems and Diagnostics 2
What type of all-wheel-drive coupling does the transverse-engine Audi TT quattro use to send torque to the rear axle?