Toyota Avensis ZZT251 2003 Service And Repair Manual page 601

14–104
CO HC
Normal High
Low High
High High
AVENSIS REPAIR MANUAL (RM1018E)
ENGINE MECHANICAL
Problems
1. Faulty ignitions:
Y Incorrect timing
Y Fouled, shorted or improperly gapped plugs
Rough idle
2. Incorrect valve clearance
3. Leaks in intake and exhaust valves
4. Leaks in cylinders
1. Vacuum leaks:
Y PCV hoses
Y Intake manifold
Rough idle
Y Throttle body
(Fluctuating HC reading)
Y ISC valve
Y Brake booster line
2. Lean mixture causing misfire
1. Restricted air filter
2. Plugged PCV valve
3. Faulty EFI systems:
Y Faulty pressure regulator
Rough idle
Y Defective water temperature sensor
(Black smoke from exhaust)
Y Defective mass air flow meter
Y Faulty ECM
Y Faulty injectors
Y Faulty throttle position sensor
http://vnx.su
– ENGINE (1AZ–FE)
Causes