Mechanical
EGR (Exhaust Gas Recirculation)
An emissions valve that routes exhaust back into the intake — a notorious carbon-clog point on diesels.
EGR valves get gummed up with carbon, especially on short-trip diesels. Symptoms: rough idle, loss of power, P0401 fault codes. A clean costs $400–$800, replacement $900–$1,800. On 4WDs that tow, an EGR delete used to be common but is now illegal in NSW and will fail an eSafety inspection.
Related terms
DPF (Diesel Particulate Filter)
A soot trap in modern diesel exhausts that requires periodic high-speed driving to self-clean.
OBD-II
The standardised onboard diagnostic port used to read engine and emissions fault codes.
Timing chain stretch
A common failure mode on VW/Audi 2.0 TFSI, Ford Ranger 3.2L and Nissan QR25 engines.
Timing belt
A rubber belt synchronising crankshaft and camshafts — must be replaced on schedule or the engine destroys itself.
Need a real inspection, not just a definition?
Aussie Auto Care does mobile pre-purchase inspections and EV battery health checks across Greater Sydney — 7 days.