Ask the Mechanic: Does a check engine light mean timing belt failure?

Hello Paul, I own a 2018 Toyota Harrier, commonly known as Kawundo, whose dashboard engine icon keeps going on and off as I drive. Does the timing belt need to be replaced?


Hello Richard, I understand the anxiety caused when you see the check engine light or MIL (Malfunction Indicator Light) on your dashboard. This amber light can mean a range of faults that affect engine running and the emission system. Faults that trigger the check engine light range from minor faults such as a loose fuel tank cap and loose circuit connector to more severe faults such as faulty ignition timing (due to timing belt wear), damaged engine management sensors or ignition coils. The check engine light should not be ignored and neither should one guess what is causing it.

The easiest way to find what is faulty is through a computer diagnosis from a technician who can interpret the fault codes. For your information, some Toyota Harrier engines are built with timing belts while others have the longer lasting (but oil quality sensitive) timing chains. You need to check the engine code of your Harrier to determine this.

Timing belts should be replaced at or before 100,000kms to avoid potential severe engine damage. Unfortunately, the vice of mileage reversal makes it difficult to know if your timing belt is due for  replacement. So, if you buy a used car with unclear service history or evidence of mileage tampering, it is best to carry out a precautionary timing belt replacement.


Hello Paul, I have just learnt how to drive. Why does the red dashboard door light of my Toyota Spacio stay on even when I switch off the ignition and remove the key? Also, when I take my car for washing, my battery gets drained. Why?


Hello Anonymous, as long as the door is open, whether the key is in or out of ignition, the dashboard door warning light should show. Light goes off when the doors are closed. Ignition on or off.

When you need to clean your car, you can switch off the interior courtesy lights above the seats. Select the off position. The courtesy lights will drain a weak car battery if left on for a while. A good battery should sustain a short time you spend cleaning the car. Try to clean the car with lights off. If battery drain persists, you ought to have the battery status examined by a battery dealer or mechanic. For now, switch the courtesy light off during cleaning.

Send sms: mycar (space) your comments and questions to 6933 or email them to: [email protected]