Published in the February 2016 issue of “Die Porsche Kassette”

I don’t mean Hanukah, tree lights or Holiday lights, and

I’m not talking about Clark Griswold’s home illuminating prowess.

Let’s discuss some of your car’s most important dash lights (aka idiot lights) and what happens when they light up like a Christmas Tree!

Believe it or not, each and every one of those lights is designed to communicate something to the driver, who, in many cases doesn’t pay the needed attention.

They are also explained in the owner’s manual but many of us never even open it, let alone read it :(

Here are some of the most common.  Please note that the warning light icons may vary slightly from model year to model year.

CEL or Check Engine Light:



A blinking CEL means that there’s a misfire detected

and running the engine could cause irreparable


If it’s on solid, it’s letting you know that there’s an

emissions issue with the car, but it is completely safe to drive.  The car’s onboard diagnostics is detecting something different from the norm.  It could be (and usually is) something as simple as a loose or missing gas or oil cap which allows for a vacuum leak.

TEMP light:

When it blinks it’s telling you that the car is low on

coolant.  Top it off.  You can use distilled water if it

needs a quart or less.  If it’s more than a quart use

50/50 premix of any coolant which contains no

sulphates or silicates.  Usually says on the label

“safe for all cars”.

But, more importantly is finding out why the light was blinking.  Low coolant level means that coolant was been lost over time.  It’s leaking from somewhere, even if you can’t see it on your garage floor.

The two most probable causes are:

1.- A bad coolant cap.  Caps are wear items which should be replaced every 5-6 years.  Look at yours (with the engine completely cold) and see if you can find a white residue around the base of the cap.  That residue is dried-up coolant that has leaked.  Go buy a new cap and install it.

2.- Your coolant system is loosing coolant when the car gets up to temp and the system builds up pressure and could be from a cracked reservoir (expansion tank), from a bad sealing water pump, a loose hose clamp or a damaged radiator, among others.  To pinpoint the leak a pressure test may be required.


Each one of your eight brake pads has a sensor inserted into it.  When the pad wears down to that sensor, the sensor makes contact with the rotor and lights up the brake wear light.  It’s letting you know that your brakes are wearing thin, but you should be able to drive several thousand miles (unless you’re on the track).  When this light comes on it’s time to replace pads and or rotors.

RESERVE light:

This one is pretty obvious.  You have about 50 miles before

you run out of gas.

TPMS light:

Tire Pressure Monitoring System constantly checks your car’s tire pressures and lets you know when they are out of spec.  Rectify the issue as soon as possible.


This one indicates that the battery isn’t charging properly.  The battery alone (without the alternator charging it) cannot run the car very long without discharging and shutting down.  It can get you a few miles so try to turn off any unnecessary accessories such as radio, A/C, interior lights, etc.

ABS light:

The Anti-lock Braking System light comes on when the computer detects a malfunction.  Your brakes will still stop the car but they won’t have the anti-lock function, so beware.

A BUNCH OF LIGHTS ON all at once:

When you turn the ignition key on before

engaging the starter, the computer turns

on all of the warning lights on so that you

can verify that they are working, but if a

bunch of them come on all of the sudden

while driving, most likely you’ve lost the

poly-ribbed belt.  This belt runs the

secondary systems such as the A/C, the

Alternator, the Water Pump and the Power

Steering pump.

So, if you loose the belt while driving, at least those warning lights will illuminate and the steering will get harder but you can still steer the car, the alternator will not charge the engine but the engine will still run, the A/C will not cool but you’ll feel air (warmer) come out of the vents and more importantly the Water Pump will not run so the engine will quickly overheat.

If you are a few miles from your destination you can probably get there but keep an eye on the temperature which can quickly start to climb since coolant is not flowing through the system.

The most unlikely scenario is that the engine has died completely due to an IMS failure or other internal failure and that is covered on another one of my Tech Articles.

For more information on dash lights and more, please visit my website:


Happy Porsche’ing,

Ⓒ2016 Technolab /