Ask the mechanic >What is wrong with my RAV4?

Hi Paul, thanks for the publications every week about cars. I have a Toyota Premio 1998 model and its really giving me a problem. It lights the engine check light and it takes minutes to go off when I start it.
They have changed plugs, picker and “ekinati” but nothing has changed.
I need your assistance thank you.

The check engine light on your car is displayed to warn you that there is an engine emission fault in your Premio. Very often this system is upset by overdue service parts.
One way to tell what the problem is, is check if you have exceeded the 100,000 kilometre service. That is when you should have changed the long life fuel filter which can affect fuel delivery pressure and the emission system.
A computer diagnosis will quickly confirm if there is another fault such as one of the sensors on the engine management system. Also confirm that your engine air cleaner is not dirty and due for replacement. I assume that you replaced your spark plugs with genuine Toyota ones

Hi Paul, I am one of your readers thanks for the good work. I have a problem with my first generation RAV4 since I delayed service by 300kms. Whenever I start the engine, revolutions do not stabilise normally and it fails to reach 1,000 rpm.
The engine revolutions are erratic up and down until it stabilises. I have done the normal service and changed spark plugs but no change. Mechanics in Kabale have told me that it’s an engine problem and some are saying I should get rid of the car. I love my Toyota RAV4, moreover it’s a manual transmission.
Can you advise.
Mbabazi Joshua,
Kabale.

Joshua, your RAV4 needs a long life fuel filter replacement and cleaning the throttle valve and idle air control valve attached to it.
This should be done by a smart mechanic using carburetor cleaner or petrol. That will fix the erratic idling and poor performance. This
RAV4 has probably passed the 100,000 kilometer mileage mark. That is when Toyota recommends that you replace or renew the long life service parts or fluids such as fuel filter, timing belt and gearbox oil. Do attend to them all. Use genuine Toyota parts to get satisfactory results. Unless your mechanics have a strong reason like poor engine compression due to oil loss, they do not have a good case to write off your RAV4 engine.

I own a corona (kibina) the gears suddenly stopped shifting. It’s automatic.
Please help.
Charles Egimu

Charles, you need a good mechanic to inspect your automatic gearbox and determine whether it has failed due to hydro mechanical or electrical causes. The automatic transmission is a combination of a mechanical system of planetary gears with clutch bands and a torque converter in the gearbox housing, a hydraulic system which includes the electro hydraulic control unit or valve body. This component houses the gate valves (solenoid switches) which receive electronic signals from the transmission computer to activate a particular gear set such as 1-3. It is necessary to periodically maintain the automatic gearbox with the correct type of transmission fluid (ATF), in your case Dexron ii or Toyota Tiv. This will provide viscous (fluid) pressure to engage the selected gears as well as lubricate the entire system to avoid mechanical damage.
Transmission failure may also be due to electrical faults such as a faulty transmission computer or failure of solenoid valves.
This can be confirmed by a car electrician or a computer diagnosis. From experience, repair of damaged gearboxes is hampered by lack of new spare parts such as replacement valve bodies or clutch bands. Use of used repair parts can provide short term solutions which are not permanent. Should the mechanic establish that the damage is mechanical I will recommend replacement with a quality used gearbox.