AutoEclinic's video: How Diagnose A Check Engine Light : Code P0420 Catalytic Converter Volkswagen Passat

In this video we have a 2002 Volkswagen Passat with a P0420. There are different ways to diagnose this code but we show you a quick way. Michael uses an infrared temperature gun to check before and after converter temps to make sure the cat is doing its job. Cost for this tool very but are well worth it. It can be an aid in many different automotive diagnostics! The automobile consist of: Powertrain: 1. Engine: • Fuel System: Purpose is to deliver fuel to the engine. It consists of the fuel tank, pump, gauge/sensor, filter, pressure regulator and injectors. • Air Intake System: Purpose is to clean and direct outside air into the engine. It consist of air filter, ducts, air plenum and intake manifold. • Exhaust System: Purpose is to direct exhaust gasses out of combustion out of engine. It consists of the exhaust manifold, converters, pipes and mufflers. • Cooling System: Purpose is to remove excess heat from the engine. It consists of water pump, hoses, radiator, thermostat, cooling fan and coolant recovery tank. Also the oil system serves as a cooling system as well as a lubricating system. It consist of oil pump, pan, filter and cooler. Drivetrain: 1. Clutch: Purpose is to connect the engine and transmission together. It consists of clutch drive disc, driven disc, release bearing, clutch fork, cable, slave cylinder, master cylinder. There are three types of clutch systems: mechanical, cable and hydraulic. 2. Transmission: Purpose is to match engine speed to road speed. Two types used are manual or automatic. These consist of gears, linkages, cables and converters for automatics. A manual is connected to the clutch by a flywheel and automatic by a flexplate. 3. Driveshaft: Purpose is to connect the transmission to the rear axle. It consists of a slip yoke, shaft and universal joints. 4. Rear axle differential: Purpose is to change the angle of motion from engine to the wheels. It also divides torque between the wheels. It consists of a ring and pinion gear, carrier, bearings, crush sleeve and axle shafts. 5. Wheels/Tires: Purpose is to provide traction to the road as well as carry the weight of the vehicle. Vehicle Control Systems: 1. Brakes: Purpose is to slow and stop the vehicle. It consists of master cylinder, brake booster (vacuum or hydraulic), calipers, drums, pads and rotors. 2. Steering: Purpose is to direct vehicle in the required direction. Consists of steering gear (rack & pinion), steering wheel, column, inner/outer tie rods, pump, reservoir, hoses and pipes. 3. Suspension: Purpose is to provide stability and handling while also providing comfort to the ride. Consists of shocks, struts, sway bars, end links, springs, trailing arms and bushings. Comfort System: 1: Heating Ventilation Air Conditioning (HVAC): Heats and cools interior air to passenger comfort. Also circulates outside and inside air. • Air Conditioning: Consist of condenser, compressor, accumulator (receiver/dryer) orifice, expansion valve, hoses, evaporator, controls, actuators and modules. • Heating: Consists of heater core, valves, hoses and switches. Electrical Systems: 1. Power Generation: Creates electrical power to run all the electrical systems. Consists of the alternator. 2. Power storage: Stores unused power to start the car and supply voltage to the alternator to create more electricity. • Both systems consist of wiring, harnesses, fuse, relays and modules.