Service engine light

[Robert D]

So what is the deal with the 'service engine soon' light? Is this an emissions check light, or does it trigger when the oil is too low? It seems to come on and off intermittently. The oil level looks to be fine, so I'm not quite sure what the light means.

 

[k20]

It doesnt mean the oil is low, it usually means some type of sensor is out of spec and needs replaced. Pull the codes on it and see what codes it has stored. Autozone can do it for you, or if you make a paperclip into a U shape, and plug it into the top 2 right ports, and switch the ign to run, it will flash the codes through the check engine light. It will flash 12 3 times, then any problem codes. When it starts flashing 12 again, any stored codes are finished.

 

[readymix]

SES light comes on when the computer detects that any given sensor is out of range. Could be anything really, from O2 sensor to the CTS, to the Knock Sensor or EGR system.....Check your codes and post up the results. On the OBD1 trucks it is as easy as jumping two contacts on the ALDL port and turning the key to "ON", then count the flashes of the light

 

[Robert D]

Sweet, I will have to do this Wednesday. I'm a busy man for the next couple days. As long as it is just a sensor and not something which will serve to be catastrophic I can live with it!

 

[sweetk30]

if its 96 and newer you need a scanner dont jump the pins like the 95 and older.

 

[K5MONSTERCHEV]

The "MIL" (malfunction indicator lamp) will set if the emissions are 1.5 times or greater what they should be. What year is the truck?

 

[Robert D]

91 GMC Jimmy 4WD.

 

[Robert D]

Ports of the? And where is it? I can find these codes today after work, but where is the port I am supposed to jump? (91 GMC Jimmy 4x4)

 

[ryoken]

http://www.cfm-tech.com/gm_tbi_trouble_codes.htm

 

[Robert D]

Thanks a lot!

 

[k20]

Yeh I did leave out the little part about where to put the paperclip didnt I?