Check engine light

malibu
engines
lights
chevrolet

#1

My 2008 Malibu service manual states that the check engine light should briefly come on when I start my engine. When the engine is cold this does not happen. Also, it happens infrequently when the engine is warm. My Chevrolet dealer says this is normal as the light checks out when tested. Chevrolet has not given me a difinitive answer on this. My concern is that if this is a problem it may surface at another time when the light should go on and cause damage if not attended to. If the manual says the check engine light should go on when the engine is started and it doesn’t, doesn’t this mean something is wrong?


#2

It certainly could. First blush guess would be a bad bulb/led or a loose wire that’s making intermittent contact, or a bad solder join somewhere that needs to be warm in order to make contact.


#3

Thank you. I am waiting for the next level of technical management at Chevrolet to reply and I will inform them of your suggested reasons. What specifically should be be checked and replaced if necessary?


#4

ECU, check engine light (bulb/led), and all wiring in between. Note that if this is not under warranty, they’re likely to charge you a lot of money for it.

When (not if, but when) they resist checking it under warranty, explain to them that you have made them aware of a potential problem in which the check engine light does not come on when it is supposed to, and will therefore be back to see them at any time in the future that massive engine damage results from your not knowing of a problem due to the light that they should have fixed not telling you.


#5

Thanks again. My auto is still under warranty till May 12th. The dealer service manager claims everything was checked and he found nothing wrong. When I receive my survey from the dealer and Chevrolet I will put your comments in writing. Meanwhile, I’m still waiting to hear from Chevrolet’s technical management team.


#6

Perhaps your engine is starting too quickly. Turn your key to the run position and pause for a second before starting the engine. You should see the light then.


#7

I have tried this a few times when the engine is cold and the check engine light did not go on.

I appreciate your comment; however, doesn’t this create an extra step in starting the engine? Also, if this step is necessary, shouldn’t the manual state that this is the way to start the engine? I should mention that all the other warning lights go on when I start the engine.


#8

Its not a necessary step, just troubleshooting.


#9

Thanks for the clarification. However, as I said earlier, when I tried going to the run position when the engine is cold the light did not go on.


#10

You might consider having a chain type auto parts store (AutoZone, Checkers, Advance, etc) scan the car to see if any codes are present. They will do this for you free.

The car is 4 years old and there may, or may not, be an applicable warranty issue even if a code(s) pops up showing a problem. It all depends.

Let me add this. You the customer deal with service writers and service managers at the dealership. Very very few of these people have any mechanical expertise to speak of and rely on words to get through the day. A lot of these words are a combination of utter BS, placebos, and sometimes flat out lying.

I’d get the car scanned at a parts house and then post back with any codes that may be present.
Please understand that I’m not tarnishing all service writers/managers as being incompetent weasels. There are some good ones but in my experience the percentage of good ones falls into the low single digits.


#11

Thank you for your suggestion. I am not familiar with the chain auto parts stores you list, but I will search one out where I live (Union county in northern NJ). What are the codes that you mention?


#12

“My concern is that if this is a problem it may surface at another time when the light should go on and cause damage if not attended to.”

Reasonable concern. Why not “break” your car and see if the light works ?
If this was my car (others may not agree with this) I’d unplug something easy to get to, an 02 sensor, coolant sensor, etc. Then the “Check Engine” light should illuminate. I’d immediately shut the engine off and reconnect the component. This test should put your fears to rest.

However, the “Check Engine” light will remain on for several days unsless somebody with a code reader (at Advance Auto Parts, Autozone, etcetera) would be so kind as to turn it off for you.

I own an inexpensive reader (Actron Pocket Scan - appx. $50) that lets me retrieve codes and turn off the CEL. You could consider owning one and becoming your own Dr. Motors, Eh.

Note: Some vehicles will clear codes by disconnecting and reconnecting the battery, but on some cars you can create different problems. I’d go the reader / scanner route.

CSA


#13

Thank you. If I had the knowledge and skills to follow your suggestion I might do it, but I’m not a Dr. Motors. Instead, I located an AutoZone shop near where I live and I’ll bring my auto in next week and see if any codes are posted. I’ll report back then.


#14

“Instead, I located an AutoZone shop near where I live and I’ll bring my auto in next week and see if any codes are posted. I’ll report back then.”

That sounds like a good idea. If there are any codes stored then you will be informed.

However, if there are no codes (and chances are there won’t be any) then you are back to your original query - “My concern [edited - inoperative “Check Engine” light] is that if this is a problem it may surface at another time when the light should go on and cause damage if not attended to.

Apparently you have spoken with people at the Chevrolet dealership and they have told you that the light works, but you still have concerns. On your next delaer visit, perhaps the nice Service Manager could demonstrate the proper functioning of the light to you by creating a temporary minor fault, like one of the ones I suggested above. It would take just a minute or two and you’d see the light illuminate and the Service Manager could turn it off, again. That would put your mind to rest.

CSA


#15

One issue with creating a fault is that most faults require that the fault be detected on two successive drive cycles. To not cause any damage, I would pull the relay for the secondary air motor.

This relay should be in the underhood fuse and relay panel. Its easy to get to and won’t cause drivability problems. It will not trip the light until the second drive cycle, but the light should come on within two minutes of starting the engine.

You can just pull the relay and after a few minutes of operation, the computer should give you a pending code of P0410. If it does, then the computer is working properly, in part anyway.