Help with Check Engine

[Skooter_NB]

I have an interesting question. I noticed a couple days ago my Check Engine light was on. I decided to sit it out, and today I was cruising on the highway and pressed down to pass this guy. When I got off the highway right after that, I noticed that the low gas light was blinking on and off, even though I had a half a tank of gas. What's going on with my car?! Please help me! Thanks.

[JRE320]

It's a malfuction and it's a sickness. :(

[GDawgC220]

usually when the reserve light is flashing, it means that the system detects loss in pressure in the gas tank --> Loose Fuel Cap!

[Skooter_NB]

Yeah, so the gas cap was loose (damn full service people not putting effort into thier job), but the check engine light is still on... :( So I guess I should just go and check that out? Does anyone think that they could be related (like the lost pressure let air into the engine or something)?

[MrSpace]

It's the gas cap

before buying my car, it made this when I was test dricing it with the girl :-|

Finally the girl called me later that night to tell me it was the gas cap.

Etienne

[MrSpace]

oops did not read your reply

If your light still on them there is maybe something. In my case it went off after putting back the cap and restarting the car

Etienne

[GDawgC220]

sometimes you have to drive it around for some miles for the check engine light to shut off. It needs to have the system realize that the cap is on tight and the pressure is correct once again.

[Skooter_NB]

Alright. I'll see how it goes when I drive around later today. I'll get back to ya'll, and thanks for the help!

[Skooter_NB]

Well, I drove it around today and the light was still on... Could I just need to fill'er up again to restore the right pressure?

[GDawgC220]

Originally posted by Skooter_NB
Well, I drove it around today and the light was still on... Could I just need to fill'er up again to restore the right pressure?

Possibly, let the tank run down and fill it up. I know sometimes that you need to drive it to accumluate a lot of miles (75 or 100 miles before it will shut off)

[slowpoke]

Originally posted by Skooter_NB
Well, I drove it around today and the light was still on... Could I just need to fill'er up again to restore the right pressure?

it may be an oxygen sensor problem also...

[Skooter_NB]

Like something is wrong with the oxygen levels, or that the sensor is broken?

[JRE320]

The solution for this check engine light is to take off the negative
cable from the battery. Wait for minute and plug the cable back.
Now if the light comes on then you got a problem. ;)
And this is the last time I gonna answer this question. ;)

[slowpoke]

Originally posted by Skooter_NB
Like something is wrong with the oxygen levels, or that the sensor is broken?

assuming that JRE320's solution doesn't work (see above), the sensor maybe broken... from what i've searched on the internet, oxygen sensors do wear out with age and that they should also be replaced periodically (somewhat like spark plugs, just a lot more expensive though ;) )

[LV202]

You can clear the code by disconecting the neg cable from the battery. Make sure you have the stereo code handy or the dealer will charge you $$$ to get it.

But this isn't going to tell you jack squat.

The CEL will not reset itself btw. It has to be cleared or have the cable taken off (not the preferred method).

There are many things that will cause a CEL. Go to autozone and have them pull the codes FOR FREE. They will have the codes and tell you what they mean, you can go from there.

It may have been the gas cap. But it may be the O2 sensor, or a misfire on a cylinder....if you just clear the code and keep driving you are going to cause much more damage down then line.

So go to AZ and get the codes and then come back here.

Good luck.

[Rocky]

The CEL light can and will reset itself if the problem is intermittant and store the codes.

I have had a MAS failure and the CEL light would reset itself a day or 2 after it goes on. This went on for a few cycles..like 4 or 5 before I changed the MAS.

OBDII Cycle Instructions:
-------------------------
A complete driving cycle should perform diagnostics on all systems. A
complete driving cycle can be done in under fifteen minutes. To perform
an OBDII Driving cycle do the following:

1.Cold Start. In order to be classified as a cold start the engine
coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of
the ambient air temperature at startup. Do not leave the key on prior to
the cold start or the oxygen sensor diagnostic may not run.

2.Idle. The engine must be run for two and a half minutes with the
air conditioner on and rear defroster on. The more electrical load you
can apply the better. This will test the O2 heater, Passive Air, Purge
"No Flow", Misfire and if closed loop is achieved, Fuel Trim.

3.Accelerate. Turn off the air conditioner and all the other loads
and apply half throttle until 88km/hr (55mph) is reached. During this
time the Misfire, Fuel Trim, and Purge Flow diagnostics will be
performed.

4.Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3
minutes. During this time the O2 response, air Intrusive, EGR, Purge,
Misfire, and Fuel Trim diagnostics will be performed.

5.Decelerate. Let off the accelerator pedal. Do not shift, touch the
brake or clutch. It is important to let the vehicle coast along
gradually slowing down to 32km/hr (20 mph). During this time the EGR,
Purge and Fuel Trim diagnostics will be performed.

6.Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-
60mph). This will perform the same diagnostics as in step 3.

7.Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five
minutes. During this time, in addition to the diagnostics performed in
step 4, the catalyst monitor diagnostics will be performed. If the
catalyst is marginal or the battery has been disconnected, it may take 5
complete driving cycles to determine the state of the catalyst.

8.Decelerate. This will perform the same diagnostics as in step 5.
Again, don't press the clutch or brakes or shift gears.

[LV202]

I've talked to many MB techs and they all have said that the CEL will not reset itself. Once it is on, it's on until it's been read and cleared. I've never seen a CEL go off by itself in ANY car for that matter.


I've seen people clear the light, not fix the problem and have it come back on....

[vas2vas]

yiap on OBD II cars CEL has to be reset... in my old OBD I bmw sometimes it went away after turing engine off, plus it could be manually reset using combinations of gas pedal presses... not as easy or sophisticated as an OBD II reader, but FREE!

[LV202]

Combo of gas pedal presses? LOL that's crazy man!

[Rocky]

you've seen? I've experienced CEL reset light by itself.

[slowpoke]

or it could be that the light bulb of the CEL blew out already :) :) :)

[Skooter_NB]

Well, my CEL light is still on and I'm gonna get the car checked out soon... I'll definitely look into all the possible reasons you all have given me. Werd. Thanks too!

[LV202]

The sooner the better.

[SLAMMED_C]

when the reserve light flashes on the cluster, it means there is purge system leak. possibly a gas cap.. but more likely the charcoal cannister shut off valve (white valve)
in some rare cases it has been the charcoal cannister or even the MOT valve.

[LV202]

Originally posted by Rocky
you've seen? I've experienced CEL reset light by itself.

I guess it fixed itself then too?

[Rocky]

It happened to my MAS.

Only explanation that it happaned was that the MAS was on it's way out. It probably triggered the CEL just once and then the MAS was semi working. Driving the car around, the computer constantly check the measurements of the MAS. If they remein in spec, the light will shut off till the next 'hiccup' occurs and store the code in it's history.

Same thing happened happened to me right now. The CEL light was on 3 weeks ago after a day it went off. Pulled the codes it triggered and it was a injector circuit malfunction and Actuator potemeter malfunction.

Same thing that happens when a loose gas cap sets off a CEL light. Screw it in tight, drive it around a few days or go through the driving cycle so the computer can check the measurements and it will reset itself. I'm not sure about OBD I cars behavior though.

My bulb is functioning..i just left the car running and pulled out the electrical plug from injector 3 and the light went on.

[Rocky]

.