how to tell if intake temp sensor is faulty?
Thread Starter
AudiWorld Super User
Joined: Aug 2004
Posts: 3,277
Likes: 2
From: Toronto
how to tell if intake temp sensor is faulty?
This is on 2001 A4 with 1.8T motor that we have in the family. The fans always come on when the car is started, even on cold days. They don't appear to stop at all.
The temperature outside was about 5 C (40 F), and the car has been parked for 5 or 6 hours.
Took VAG-COM to it, took measurements of intake temperature sensor. The readings I got were about 21 Celsius (70 F ) at idle, dropped a few degrees when I hit the accelerator (I'm guessing it's sucking the air at a faster pace, so it's cooler).
It's odd that the temp reading was so high.
Any insight is appreciated.
The temperature outside was about 5 C (40 F), and the car has been parked for 5 or 6 hours.
Took VAG-COM to it, took measurements of intake temperature sensor. The readings I got were about 21 Celsius (70 F ) at idle, dropped a few degrees when I hit the accelerator (I'm guessing it's sucking the air at a faster pace, so it's cooler).
It's odd that the temp reading was so high.
Any insight is appreciated.
AudiWorld Super User
Joined: Jun 2008
Posts: 2,284
Likes: 100
From: Fallbrook, CA
I don't think that the air temp sensor has anything to do with running the fans. Coolant temp is what you want to look at, plus that sensor is far more likely to be troublesome. Your car may also have a thermoswitch on the radiator, you could disconnect that and see if the fans run when cold. I've had to change one of those before. As to the intake temp reading, remember that the air passes through the compressor side of the turbo, which can be quite warm, so to see if the sensor is accurate, you may have to remove it from the intake manifold.
Super Moderator
Joined: Sep 2009
Posts: 9,250
Likes: 480
From: Boston MA
I like to use VCDS to check the temp sensors after the car sits overnight.
The various sensors should be reading close to ambient air. Check your engine coolant temp reading. See if it looks wacky.
The various sensors should be reading close to ambient air. Check your engine coolant temp reading. See if it looks wacky.
Thread Starter
AudiWorld Super User
Joined: Aug 2004
Posts: 3,277
Likes: 2
From: Toronto
yeah, to my surprise, the engine coolant temperature was reading between 86 to 90 degrees F within a minute or two of starting the car. That seems too hot since the ambient temp was 40.
however, would coolant temp of 90 F turn on the fan?
however, would coolant temp of 90 F turn on the fan?
AudiWorld Super User
Joined: May 2002
Posts: 5,138
Likes: 4
From: Redmond WA
Your Audi should run about 91C , make sure you are not mixing up units.
At 90F only the electric fan would be running with the AC on. Below 40F ambient the AC could be blocked by the outside air sensor so the fan won't run. Check for the snowflake in the cluster.
Thread Starter
AudiWorld Super User
Joined: Aug 2004
Posts: 3,277
Likes: 2
From: Toronto
No, I am not confusing my units of measurement. All my readings were done in Celsius, I converted to Fahrenheit for the forum. Ambient - 5C, air intake temp - 21C, coolant temp - 32C.
I switched to Econo mode on the HVAC controls, but the fan still spins.
I switched to Econo mode on the HVAC controls, but the fan still spins.
Thread
Thread Starter
Forum
Replies
Last Post
fusion1127
A8 / S8 (D2 Platform) Discussion
0
Oct 13, 2013 03:59 PM
GTA_Driver
A6 / S6 (C5 Platform) Discussion
0
Nov 17, 2011 07:25 AM
