Serviec Engine Soon light

[Buckwheat]

Hi Folks,

I recently bought a 2002 GMC 2500HD with the 6.0

It has about 212k on it , yet the oil pressure and motor seem very good. However my service engine soon light came on and I hooked an OBII to it and it said a knock sensor was crapping out, so I figured I would replace both with AC Delco and a new OEM wiring harness for it too since folks have been complaining about the aftermarket products throwing knock sensor codes again, just after replacing the sensors.

 

Question: Would the service engine soon light point out a knock sensor before the check engine light came on and threw a code for a OBII?

Forgive my ignorance but this is my first GM product since 1984 and I honestly dont know if this truck has a both ( service engine light and check engine light)

Thanks for any help

[davester]

I don't believe there are separate 'check engine' and 'service engine soon' lights...

[Buckwheat]

Hi Davester, thanks for your help! So the service engine soon light is the same as a "check engine" light as in other vehicles? And I can use the OBII for code reading when the "Service Engine Soon" light is lit up?

[Swimmer8366]

No it has just one check engine light

 

Sent from my Z981 using Tapatalk

[Swimmer8366]

 

Sent from my Z981 using Tapatalk

[Buckwheat]

Hi Thanks! Whew...it is a steady light, but when hooked to the OBII it indicates a knock sensor as the culprit, so I guess I will have something to do this coming weekend by replacing the harness and the two sensors with AC Delco stuff...I have seen the horror stories of using after market knock sensors...folks are going back in there 2-3 times to fix it because of faulty after market knock sensors.

 

I was unsure if I had two separate issues...one from the OBII reading I was getting but not in conjunction with a typical "Check engine" light illuminated and another from the "check engine soon" light,,,just didnt know if I actually had two on this vehicle.

Thanks again folks...you guys are great!

[davester]

To do it, you also need to replace the intake manifold gasket (as the knock sensors are underneath the intake manifold). So it carefully and torque the manifold bolts down in the correct order, as it is a fairly common problem for the intake manifold to leak.

[Buckwheat]

Thanks folks!

I have the intake manifold off and are going to replace the knock sensors and harness with OEM stuff today...It appears some folks are putting some high temp RTV around those rubber plugs...will do that too.

Davester, thanks for the the info, I also got new intake manifold gaskets too...will clean everything up before install.

I hope this is a first time-last time install....I went all OEM after reading horror stories of folks having to go back in 2-3 times because of aftermarket parts.

 

 

Update: Ok after reinstalling everything and doing some test driving...everything seems ok. The service engine soon light went out within seconds of changing out the knock sensors.

While I was in there I went OEM all the way, I got the knock sensors, sensor harness, High temp rtv'ed the plugs in place and replaced the throttle body gasket too....no more lights and it purrs like a kitten.