Ask a Mechanic: Flashing lights

Dear Ask a Mechanic,

I have this annoying problem with my 2009 Honda Fit that I’m hoping you can help me with. The check engine warning light has been permanently on for at least the last three years, even though I’ve had major work done to the car as well as regular maintenance. Mechanics don't seem to know how to turn it off, not even the Honda mechanics.

The D (drive) indicator light has been flashing for at least as long, and lately the indicators for windshield wiper fluid and the antilock braking system are also constantly on. I no longer trust any of these lights. Is it possible to disable them all? This is important as I'm trying to sell the car, which is otherwise in great operating condition and has low mileage. – Lights On

Without being able to run a diagnostic scan to see which systems are reporting issues – and if there’s any commonality between them – it’s difficult to do much more than speculate. Solely based on what’s shared by those systems, the gauge control module ties into most of your Honda’s electronics through a pair of communication networks. Theoretically, a defective gauge module could cause false indications. This is unlikely, though.

A flashing drive light in a Honda denotes a transmission-related problem, which could illuminate the check engine light as well. Some antilock braking system faults can affect several systems and illuminate multiple malfunction indicators. I’ve encountered this before, including in a Fit with a faulty rear wheel speed sensor. The washer fluid light could be related, or simply due to a no longer fully buoyant sensor float.

I still believe that a skilled technician, using proper equipment, should be able to determine the cause of the warning lights.

A serious concern here is your desire to disable those lights in the name of making the vehicle more saleable. Even putting the moral arguments aside, there are potential legal ramifications to disabling a safety system warning indicator, like the one for the antilock braking system.

Unfortunately, with so many variations in equipment and test displays, even if a buyer were to take the car for a pre-purchase inspection – which is always a good idea – it’s quite possible that a technician wouldn’t notice that any secondary indicators were missing.

Also, while this doesn’t apply to your 2009 Honda, vehicles built on or after September 1, 2011, are required to have their stability control indictor light and system – which incorporates the antilock braking system – functioning to pass an Ontario safety standards certificate inspection.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.