2014 TDI - Glowplug light - Engine Light
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AudiWorld Member
Joined: May 2011
Posts: 63
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From: St Louis MO
2014 TDI - Glowplug light - Engine Light
Replaced oil and ERG coolers by pulling the intake manifold (not an easy job)
Once complete started getting a intermittent glow plug light (flashing, but not always)
Now I have the light all the time and a engine light also
Ran the Vagcom - Have:
4527 4531 - Coolant Fan Control Circuit
16545 16547 - Implausible Data Received from Glow Plug Control Module
Where do I start on troubleshooting?
JPJM
Once complete started getting a intermittent glow plug light (flashing, but not always)
Now I have the light all the time and a engine light also
Ran the Vagcom - Have:
4527 4531 - Coolant Fan Control Circuit
16545 16547 - Implausible Data Received from Glow Plug Control Module
Where do I start on troubleshooting?
JPJM
AudiWorld Senior Member
Joined: Mar 2017
Posts: 1,616
Likes: 517
From: Fairbanks, Alaska
My first thought when I see an implausible signal is that something didn't get plugged in properly upon reinstall. I am not sure which plug or combination of plugs is associated with that module, but if you took photos of the space before working (SOP for me... learned the hard way!), compare those closely with what you did. Even if you plugged in everything well (seated/connected), several of the plugs are very easy to swap around (for example, the grey and orange plugs do not connect to their same colors on the other side). Since you have two errors, it is very possible that this is the issue.
AudiWorld Super User
Joined: Jan 2021
Posts: 4,567
Likes: 1,456
From: USA - NM
+1
Likewise, it's always a good idea to look at the time/date stamp contained (VCDS data) on each fault code shown to see what is popping up first.
The 'cooling fan control circuit' is normally associated with the radiator outlet coolant temp sensor, but definitely look up that code on Ross-Tech Wiki page online. Those coolant temp sensors are a known failure point, but they can act up if air bubbles remain inside the cooling system. Take a quick reading on the coolant temp sensors on VCDS on cold engine is easy way to determine if either or both coolant temp sensors are needing attention, or not. You can pull other fluid temps and ambient air temp as well for comparison on cold engine.
I did have issue with cooling fans running and fault code popped, and it was that temp sensor. It's an $8-10 sensor if you order it or buy it locally and can be much more expensive, but check the live data first.
Likewise, it's always a good idea to look at the time/date stamp contained (VCDS data) on each fault code shown to see what is popping up first.
The 'cooling fan control circuit' is normally associated with the radiator outlet coolant temp sensor, but definitely look up that code on Ross-Tech Wiki page online. Those coolant temp sensors are a known failure point, but they can act up if air bubbles remain inside the cooling system. Take a quick reading on the coolant temp sensors on VCDS on cold engine is easy way to determine if either or both coolant temp sensors are needing attention, or not. You can pull other fluid temps and ambient air temp as well for comparison on cold engine.
I did have issue with cooling fans running and fault code popped, and it was that temp sensor. It's an $8-10 sensor if you order it or buy it locally and can be much more expensive, but check the live data first.
Last edited by '10Q7TDI_Prestige'; Jul 9, 2025 at 03:39 PM.
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