Check engine light is on?

JOSEPH529

MEMBER
1 POST
1992 FORD F-150
5.0L
V8
2WD
AUTOMATIC
74,000 MILES

Check engine light is on a a tough idle is happening until I hook up a scan tool and then the check engine light cuts off and it idles smooth as butter.

Was this

answer

helpful?

Yes

Thursday, September 10th, 2020 AT 10:37 AM (Merged)

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

There should be no change by hooking up a scan tool. If there is, you may have a bad ECM.

The ECM Lower LH Side Of Safety Wall, Below Brake Fluid Reservoir

What scan tool are you using?

Roy

The Electronic Control Assembly (ECA) stores information about vehicle operating conditions and uses this information to compensate for component tolerances. When an emission related component is replaced, Keep Alive Memory (KAM) should be cleared to erase the information stored by the processor from the original component.

To clear the KAM, disconnect the battery negative terminal for five minutes or more. Drive the the vehicle for at least ten miles to allow the ECA to relearn the values for optimum performance.
Note: During the ten mile relearn drive, the vehicle may exhibit some driveability symptoms. These should be eliminated when the KAM has relearned the operating values.

Image (Click to make bigger)

SPONSORED LINKS

Was this

answer

helpful?

Yes

Thursday, September 10th, 2020 AT 10:37 AM (Merged)

RL9106

MEMBER
2 POSTS
FORD F-150

I just bought a 1994 ford f150 and after a couple of days the check engine light came on. I'm not that much into cars so I don't really know what I should do. Anybody know what I could do to turn the light off?

Was this

answer

helpful?

Yes

Thursday, September 10th, 2020 AT 10:46 AM (Merged)

EPYON2K1

MEMBER
15 POSTS

Dude you can't really just turn off the Check engine light.

The check engine light works this way.

Hypothetically :
Ok so the light is on, because it's receiving a signal from let's say the transmission's fluid sensor. The sensor is on and sending an error code to the computer in your dashborad because the level of fluid is low.

Now are you just going to get this "turned off" and ignore the low fluid level? Don't kck the car when the transmission goes out on it. Kick the user. Remember the machines only do what the operator wants them to do.

Get this light checked out at aamco, autozone, somewhere!

Then they will give you a trouble code, P0****,
Could be your EGR, Tranny, Engine.

Could be serious or not, but get it checked out.

Was this

answer

helpful?

Yes

Thursday, September 10th, 2020 AT 10:46 AM (Merged)

PEPPERMRJ

MECHANIC
1,158 POSTS

You can retrieve the codes on an OBDI system yourself without a scan tool. Check your manual for the procedure. If you don't find it post back. The light will go out if the problem somehow rectifies itself (A loose connection). You can also clear it by disconnecting the battery. It will just reset tho if the problem still exists. Best to pull the codes and post back. The OBDI codes don't have the PO numbers, just normally 2 digits (12 or 53 for instance) or up to 3 digits.

Good luck. :)