Are My Glow Plug(s) Bad?

[yarmo]

Just got the blinking glow plug light (as well as a check engine light with several codes) when I went to start. It will blink like this for a while, then eventually it lets me switch the Jeep to off, then it starts up fine.

Is this a bad glow plug indicator? If it is, can I run it like this for a few days? I have a camping trip scheduled this weekend, and I really doubt the dealer can get it turned around that fast... I'm assuming this is covered under my extended warranty since I've only got 55k miles?

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[JL.FR]

Hi Jack, when starting the car and the glow plug light is flashing along with other lights, it's likely the problem isn't the glow plugs, but I would say it could be a sign of low battery voltage. the jeep is 4 years old and the battery could be 5 years old. Have the battery tested and bring jumper cables.

 

[yarmo]

Hi Jack, when starting the car and the glow plug light is flashing along with other lights, it's likely the problem isn't the glow plugs, but I would say it could be a sign of low battery voltage. the jeep is 4 years old and the battery could be 5 years old. Have the battery tested and bring jumper cables.

Ok I’ll do that. I have deleted the aux battery already.

What’s interesting is when I go to start it, it will always do this. Then I can shut it off then try to start one more time and it turns over perfectly? That’s why I was leaning towards glow plugs.

 

[BDinTX]

I don't know jack about glow plugs but also would suspect battery issue.
2021 diesel
2022 eliminated aux battery
2024 replaced main battery correcting intermittent Water in Fuel warning
2025 battery monitor reporting battery bad, cranking voltage dropping to 9.51v

 

[yarmo]

Went and got my battery checked, auto zone said it looks fine and has 600 cca still?

 

[yarmo]

But.. I have also been getting intermittent water in fuel messages… I might just replace it anyway to see.

 

[BDinTX]

Have you been watching your voltage while driving? I've been seeing mine charging at 14.5v lately, I really think the charging system is trying like heck to keep the battery alive.

 

[yarmo]

So I leave my jeep for multiple months at a time, but I keep it on a trickle charger. Wondering if it’s just not holding it well enough while I’m gone.

I’ll check the voltage in a little bit good idea.

 

[yarmo]

My voltage looks normal, so I'm leaning towards this not being a battery issue.

What's interesting is I can clear the check engine codes and leave my jeep for a while, then when I come back and start it up it's fine no issues. However if I shut it off then immediately go to start it, that's when the glow plug light and check engine codes show up.

 

[JL.FR]

Hello Jack, Onboard computers behave erratic when they detect low current during startup. Testing the battery without putting it into startup mode is not enough. A battery at the end of its life is detected at maximum charge, during startup in winther with the lights on.

 

[yarmo]

Ok, you've all convinced me, I'm ordering a new battery stay tuned...

 

[BDinTX]

I haven't been impressed with my Walmart Everstart, it appears to be fairing worse than the factory one.

 

[grimmjeeper]

My Die Hard AGM from Advance Auto is running strong over 3 years now.

 

[yarmo]

I’ve replaced my battery, but I’m unfortunately still getting the glow plug light flashing at startup. However, I do think the battery did resolve some of my problems as my intermittent water in fuel message has vanished!

 

[yarmo]

Well, it's with the dealer now. Fingers crossed my warranty covers whatever it is!

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