Avensis 2001 Mileage 115,000 One month ago, warning light comes on. Service is due anyway. Regular garage (not Toyota dealer) does service, identifies faulty oxygen sensor (there are 3, the faulty 1 is on the left exhaust manifold). Orders replacement sensor. Takes 2 weeks to arrive (remember earlier this year there were major problems with contaminated fuel from Tesco that damaged oxygen sensors on a wide range of cars).
Replacement fitted, warning light cleared.
2 weeks later, after driving about 1000 miles, warning light on again. Garage says their diagnostic kit shows "no fault found". They clear the warning light. 3 times since, I drive anything from 10 to 30 miles, warning light comes on. Garage clears light, again says "no fault found": repeatedly.I ask at Toyota dealer. They say their diagnostic kit never reports "no fault found". Is this believable? What about an intermittent fault?
Is there any published information about what faults cause the warning light to come on?
Any ideas gratefully received ...
-- Graham