Credit: vbxmaxima

So there you are, happily driving your Max like I was, when the dreaded Check Engine Light came on. There is a simple procedure you can do to find out what’s wrong without having to take it to a dealer.

So there you are, happily driving your Max like I was, when the dreaded Check Engine Light came on. There is a simple procedure you can do to find out what’s wrong without having to take it to a dealer.

1. With the car parked and the engine off, pick up a flat head and phillips screwdriver.

2. The ECU is located by your gas pedal and is protected by a plastic cover.
Remove the cover by a quick twist of two screws:

You’ll find that the screw heads will pop up. Gently, but firmly pull the screws out – they’re the plastic snap-on type.

3. Remove the panel to expose the ECU. The Diagnostic Test Mode Selector is the screw indicated by the arrow.

4. Here is a close up of the screw. It is protected by a warning sticker.
You’ll have to poke through the sticker to get to the Selector screw.

If you have a hard time reading what the sticker says (like I did) here’s what it says:

DO NOT FORCE PAST STOP

AFTER PERFORMING SELF DIAGNOSIS
TURN SELECTOR FULLY COUNTER-CLOCKWISE
TO STOP

5. Put your key in the ignition. Turn your key to “ON” but don’t start the car.
Your dash lights and the check engine light will come on.

6. With a flat head screwdriver, turn the ECU selector screw clockwise until you feel it go against the stop.

7. After waiting for at least 2 seconds, turn the selector counter-clockwise until it’s stop.

8. Now watch your check engine light. It should be blinking at you. You will see a series of slow blinks or pulses, followed by a series of quick pulses. You need to count each type. If you missed it, don’t worry, it will continuously repeat. The trouble codes are 4 digit numbers. The long pulses represent the first two digits and the short pulses the last two digits.

Note: If there is more than one error code, they will be displayed in sequence.

FOR EXAMPLE:

(LONG PULSE) (LONG PULSE) (LONG PULSE) (SHORT PULSE)(SHORT PULSE)
….means trouble code 03 02

ANOTHER EXAMPLE:

(LONG PULSE)(SHORT PULSE)(SHORT PULSE)(LONG PULSE) (LONG PULSE)(SHORT PULSE)
…means you have TWO trouble codes: 01 02 and 02 01

9. Got the codes? Good! Time to find out what’s wrong. Time to use the ECU Decoder!

10. Now that you found the codes and what they mean, it’s up to you whether you want to take it to a mechanic or fix it yourself.

11. If you do fix it yourself, don’t forget to reset the check engine light! The check engine light will not go away if you don’t, even after the repairs have been made.

RESETTING THE CHECK ENGINE LIGHT

To reset the engine light is a simple procedure.

  1. Turn the selector screw clockwise to its stop.
  2. Wait 2 seconds.
  3. Return back by turning the screw counterclockwise to its stop.
  4. IMMEDIATELY REPEAT steps 1 to 3.

The next time you start your engine, the check engine light should go away!