Coolant Temp Sensor Voltage Readings?!

Thread Tools
 
Search this Thread
 
Old Aug 10, 2018 | 07:43 PM
  #1  
Sufarry's Avatar
Thread Starter
|
Junior Member
Joined: Jul 2018
Posts: 20
Likes: 0
Default Coolant Temp Sensor Voltage Readings?!

As you guys know, still having ECT issues....

okay, so this is the reading I was getting from the ECU pins with the ignition ON and the sensor plugged in...

this cant be right?

Pin 5 ( ground ) and pin 13.

No voltage readings?

I do get ~2.0ohms when I test for resistance, which I think is normal for 75 degrees F.

 
Reply
Old Aug 11, 2018 | 07:14 AM
  #2  
act1292's Avatar
Senior Member
Joined: Jan 2006
Posts: 1,792
Likes: 52
Default

There won't be any voltage reading if the connector is not connected to the ECU. To get a voltage reading, the connector has to be connected to the ECU and you need to back probe the connector - that means probe from the wire side.

According to the FAQ at brickboard, the resistance should be as follows:
  • 32F (0C)-- about 6000 ohms within a range of +/- 10%
  • 68F(20C) -- about 2300 ohms
  • 104F(40C) -- about 1300 ohms
  • 140F(60C) -- about 600 ohms
  • 176F(80C) -- about 300 ohms
  • 212F -- about 190 ohms
What was the resistance with the engine warmed up?
 
Reply
Old Aug 11, 2018 | 07:26 AM
  #3  
Sufarry's Avatar
Thread Starter
|
Junior Member
Joined: Jul 2018
Posts: 20
Likes: 0
Default

Originally Posted by act1292
There won't be any voltage reading if the connector is not connected to the ECU. To get a voltage reading, the connector has to be connected to the ECU and you need to back probe the connector - that means probe from the wire side.

According to the FAQ at brickboard, the resistance should be as follows:
  • 32F (0C)-- about 6000 ohms within a range of +/- 10%
  • 68F(20C) -- about 2300 ohms
  • 104F(40C) -- about 1300 ohms
  • 140F(60C) -- about 600 ohms
  • 176F(80C) -- about 300 ohms
  • 212F -- about 190 ohms
What was the resistance with the engine warmed up?

Thank you for the reply! I'm not very handy with electrical stuff, but I'm learning .

I didn't check the resistance when it was warm. I have 3 ECT's. 2 brand new ( ordered an extra because I thought it was faulty ) and the original one that came in the engine when I got the car. So, my problem is with the original sensor, the car starts up when cold, but does not start up when warm ( have to feather the throttle quite a lot ). So, I replaced it with a 12$ one from IPd. Well, with the new sensor the car doesn't start when cold... and it throws a CEL for Coolant Temp Sensor Missing or Faulty... I then tried my even NEWER sensor ( replacement for my new one, since I thought it was faulty ) and it does the same exact thing. So, I replaced it with the original sensor, and it starts up like normal, but of course it still has the hot start issue

I talked to IPd yesterday, they are sending me a BOSCH ECT, so hopefully that will fix it.. But I can't see why the other 2 BRAND NEW sensors would be faulty? The resistance reading was normal. I haven't had a chance to try them when the engine is warm because it kills my battery trying to turn it over long enough to get it started. I may go home today and boil them and see what the readings are. Either way, it should still start the car when cold given that the room temperature readings from all 3 of the sensors are within normal range...

Any ideas?
 
Reply
Old Aug 11, 2018 | 01:51 PM
  #4  
pierce's Avatar
no mo volvo
Joined: Oct 2010
Posts: 11,289
Likes: 109
From: 37 North on the left coast
Default

2 K Ohms (aka 2000 ohms) would be in normal range, 2.0 ohms would most assuredly not be.
 
Reply
Old Aug 11, 2018 | 02:09 PM
  #5  
Sufarry's Avatar
Thread Starter
|
Junior Member
Joined: Jul 2018
Posts: 20
Likes: 0
Default

Originally Posted by pierce
2 K Ohms (aka 2000 ohms) would be in normal range, 2.0 ohms would most assuredly not be.
i meant 2000. It shows 2.0 due to the setting on my meter.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Squirt
General Volvo Chat
5
Dec 29, 2020 02:53 PM
Sufarry
Volvo 240, 740 & 940
9
Jul 30, 2018 11:24 AM
bobinyelm
Volvo 240, 740 & 940
11
Aug 2, 2013 02:03 PM
jdh0921
Volvo 240, 740 & 940
7
Aug 26, 2008 12:57 PM
Snooky
Volvo 240, 740 & 940
1
Feb 16, 2006 11:38 AM




All times are GMT -5. The time now is 06:09 PM.