My SES Light was on. Pulling the codes told me it was glow plugs. With 125K on my 2000 Excursion I figured it was about time to replace them. Well, I put in the new Glow Plugs but the SES light still comes on with the same codes
Anyway to trouble shoot what might be causing it (i.e. Relay, module or harness). Any recomendations?

Thanks

 

What was the code? With the code we could give you the diagnostics to fix the problem. Does the truck start easily when it is cold or are you having cold start issues? You see, without more info, it makes it hard to pinpoint the problem...

 

Welcome to FTE. Like Neal asked, how does the truck start? What part of the country are you in, and how cold is it there? Your Excursion has the California style GPCM (glow plug control module) which is set to throw a check engine light for glow plugs.

There's a chance your GPCM is bad. If you get a test meter you can check for power immediately after the key is turned on at each of the wires coming off the GPCM. Depending on temperatures and conditions, the glow plugs should come on for 0 - 120 seconds, so you don't have a lot of time to check.

 

Sorry, should have posted the codes in the first place, but I was lazy Just went out and pulled them:
P0470 - Actually this is a new one
P0672
P0674
P0676
P0678

I think those are the cylinders on the drivers side. Before I replaced the Glow plugs, it was more variable.

Live in Austin TX, we have had some cold weather, but nothing extreme. The truck starts easily in the mornings.

 

Welcome to FTE, Hookster.

Here's what I get for those codes:

P0470 Exhaust Back Pressure Sensor Circuit Malfunction
P0672 Glow plug #2 circuit failure
P0674 Glow plug #4 circuit failure
P0676 Glow plug #6 circuit failure
P0678 Glow plug #8 circuit failure

 

Ryan beat me to it. You are correct about those being the drivers bank glow plugs.

With one whole bank failed you may have a faulty GPCM since it's hard to believe you would have 4 new ones fail all on the same side.

First check the 9 pin connector at the valve cover and the connector at the GPCM to make sure they're not loose. Unplug them (drivers side harness) and make sure none of the pins inside the plugs are messed up. If you can follow the above diagram and have an OHM meter, check resistance in the glow plug wires. They should OHM out less than 5.

Before we get into the EBP sensor, can you confirm that was a P0470 code and NOT a P0670 (glow plug control circuit malfunction)?

On another note, did you make sure after replacing the glow plugs that NONE of the wires on the harness under the valve cover (UVCH) would rub against a push rod or anything under there? If the truck starts running rough and you see a P1316 the first place to check will be those wires.

 

Thanks. Yes I was careful about the wiring (thanks to these forums) nothing should be rubbing. I'll check out the connection you referenced and try and check the resistance ( not a wizard with my multi-meter).

I can verify that the code is P0470, I checked it twice.

Thanks for the help so far!


Oh, found my old ID. I'm the original poster

 

Then disregard the welcome and we'll just say welcome back.

You can try wiggling the wires on the EBP sensor to make sure nothings loose. I've seen some debate on this, but many guys swear by cleaning out the tube. A write up on that is here. http://guzzle.rbmicro.com/ebps.html