Ask the Mechanic


Of late, my Toyota Regius does not pick speed. Instead, when I step on the accelerator pedal, it just makes a lot of noise. What could be the problem?

John David

Hello John, you have not mentioned whether your Toyota Regius is the diesel 3.0 litre 1KZTE engine or the 2.7 litre petrol 3RZFE. I will point out the checks you need to carry out for both engine types, with the symptom of poor acceleration and engine power loss. With the 1KZTE turbo diesel engine, loss of power can be caused by simple service issues such as a dirty air filter or diesel fuel filter. Whereas your next service appointment may not be due, the use of adulterated diesel fuel or travel on very dusty roads may clog the fuel and air filters.

Ask your technician to check all vacuum hoses in the engine air intake for leaks, especially the ones to the turbo system. A noise in the engine when you accelerate may be because of a damaged turbo charger. This tallies with the engine lack of power when you accelerate. Check the turbo charger for oil and vacuum leaks or mechanical damage.

In case your turbo operation is okay, then your technician should check fuel delivery pressure from the injectors. This will determine whether you need to service or adjust your fuel pump or injector nozzles. This procedure is best carried out by a fuel injector pump specialist.

For the 3RZFE 2.7 litre petrol engine, your mechanic ought to check the condition of the air cleaner element, spark plugs and fuel filter. In case these components are okay, then consider a diagnostic check to report the performance of the mass air flow sensor.


I own a RAV 4 ACA31W 2007 240G, a Japanese domestic market version. Its audio/DVD and Navigation system is in Japanese. It has Japanese voice prompts when you start the car, and most labels/inscriptions are in Japanese too. Is there an expert in Japanese to help me out?


Hello Godfrey, unfortunately, some car audio systems with navigation facilities made for the Japanese domestic market are programmed with only the Japanese language option. Unlike some universal systems that have international language options to select, yours may not have that facility.

However, you can drive down to Katwe or Kisekka market where importers of used car radios will get you a decent and affordable alternative which fits in your car. This will end the frustration of not knowing how to navigate around your audio system.


I drive a 2001 Benz S500. When I lock the car with central locking system, the door locks do not engage. Why? Christopher.

Dear Christopher, the central door locking system of your Mercedes S500 relies on an electro pneumatic system to actuate the mechanical locks. The central locking system is actuated electronically when you press the dashboard mounted switch or press your remote key fob.

However, the central locking system relies on a pneumatic (vacuum pressure) pump to drive the mechanical locks. When your central locking system fails, you must inspect the electrical, pneumatic or mechanical components in order to find the fault. A good technician should be able to establish whether there is power supply to the central locking control module located in your boot side wall.

If you refer to your fuse assignment, you will identify the fuses for this system. Confirm that they are not damaged or corroded. Check the pneumatic pump to confirm that it is powered to release sufficient vacuum and the vacuum lines do not leak. You may need to strip some of the lower floor panels to inspect the vacuum lines in case any is broken or twisted.

Finally, test the driver door lock to confirm that it receives the electrical signal and responds mechanically.


I drive a Toyota Vista Ardeo which starts perfectly but will not move until after five minutes. What causes this delay? Robert.

Hello Robert, what you describe sounds like poor engine response or acceleration. There are a few factors that cause this sort of engine problem and all have something to do with the ignition system. You need to confirm that your engine has a clean and unrestricted supply of fuel, air and spark. Ensure that your engine fuel filter has been replaced, it is the long life type fitted in the fuel tank and should be replaced by 80-100,000. Often, it is neglected and tends to affect the performance of the fuel pump.

Also, make sure you have the correct genuine Toyota spark plugs and a clean air cleaner element. Should your symptoms persist, make sure your engine has no vacuum leak and the throttle valve movement is not restricted by soot.  D4 engines such as the one in your car are sensitive to regular service with genuine parts. Let me know how you get on after checking the suggested areas.


Hello Paul, when I put my Corolla S 2005 in reverse, it sometimes goes on smoothly or the car will jerk as if it is on hand brake. My mechanic has tried to service the gear box to no avail. What should be my next course of action?


Hello Bitrus, I presume your mechanic has checked the gearbox mounting (suspension) as it can cause a slight jerk when you shift. If the jerking is severe, have the automatic transmission carefully diagnosed to rule out transmission fluid (ATF) restriction, usually caused by a dirty or restricted ATF filter in the gearbox, even after you change just the ATF.

A computer diagnosis would be a useful way to examine the automatic gearbox electrics, particularly the valve body solenoids, which control and allow flow of ATF to particular gear bundles. The automatic gearbox valve body and solenoids will get damaged when you fail to renew the ATF fluid and it starts to overheat or becomes very dirty with sludge, which damages the valve body and solenoids.

When the valve block or solenoids are damaged, they will restrict ATF flow, which can cause a jerk when you demand performance by accelerating. A faulty transmission pump will also cause that sort of jerk, even after you service the gearbox.

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