grrrrr! glow plug codes

[rickricca]

Hi all

I am hoping to pick some brains re my just purchased 99 7.3

I didn't know you now have to smog these things in CA

I had a glow plug controller error bank one.
Showed two bad plugs with resistance test at Valve cover plug
Replaced all glow plugs and harnesses (tested the new ones before installing)


Now I am getting P1393 GPC low input bank 2

P1391 Low input bank one

and P0380 Glow plug control circuit

I must have missed something

any thoughts?

I am grateful in advance

 

[DaveBen]

Make sure the Under Valve cover wiring harness is connected to each connector and correctly. Loose connections are equal to no connection.

Dave

 

[rickricca]

Thanks Dave, will do the resistance check at the valve covers tomorrow. I didn't change the glow plug relay, 8 working plugs instead of 6 might have finished it off. Think I will try that if my resistance measurements check out

 

[JLDickmon]

see if the Powertrain Control Module is grounding the glow plug relay by taking a test light or voltmeter and checking for near battery voltage on the purple/orange wire while the Wait To Start light is on.
If you have a logic probe, simply disconnect the wire while you are changing the GPR and check it for a ground signal then.

hopefully, it's just the low amp side of the relay open.

 

[JLDickmon]

and Welcome to the Forum!

 

[JLDickmon]

Hey.. is this a Federal or California emissions truck?

I just remembered that the California trucks use a Glow Plug Controller along with the PCM and relay..

Means we might have one more F.R.E.D. to diagnose..

 

[rickricca]

it was the relay. I changed it and now it doesn't (as of last nite) throw any codes at all. Need to daily drive it for a bit and see if it holds. If it does, it's smog check time Thanks for the replies

 

[rickricca]

Now I have the p1000 not ready code. This is what got me kicked out of the smog test last time around. Hopefully enough successful drive cycles will make this code go away?

Thanks for the brain picking

 

[JLDickmon]

P1000 means it hasn't completed a drive cycle.

I would venture a guess they boot you from emissions testing for it to make sure you didn't clear the codes in the parking lot prior to testing.

If you drive it enough cycles it will clear itself, OR..
Clear it and put your tester away. As long as you don't retest before a drive cycle is complete, it won't generate.

 

[01yellerCobra]

You can't clear the P1000 code with a tester. The only way to do it is to drive. That's the reason they put it there. Every time you flash your computer or disconnect the battery it pops up. You should be able to find the steps online.

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