Coolant Sensor

Alex1888

Active Member
Oct 26, 2020
62
21
Got a new battery installed this morning and went out a run. When I got back I checked the battery charge capacity and it was only 75 percent so looks like I have a drain somewhere so tomorrow will be a day of pulling fuses I think or I have a dodgy wire somewhere. On the plus side the car didn't lose power or go in to limp mode.
 

DEAN0

Old Git
Feb 1, 2006
5,297
305
Preston - UK
Got a new battery installed this morning and went out a run. When I got back I checked the battery charge capacity and it was only 75 percent so looks like I have a drain somewhere so tomorrow will be a day of pulling fuses I think or I have a dodgy wire somewhere. On the plus side the car didn't lose power or go in to limp mode.
Measure the voltage over the battery with the engine running - make sure the battery is charging.
 

BillyCool

Active Member
Jan 16, 2020
655
249
Leicestershire, UK
The coolant temp sender in the block is a real pain to get to and change. I had mine done a few years ago and my mechanic said it was a right pain - he had to take out the airbox, pipework and other bits to get to it.

I fitted a new battery recently on my 2014 TDI as the older one would not charge above 60%. Certainly stopped the known long cranking issue.

Hope you get your issues fixed. If you Google `paracitic battery drain`, there are some useful pages on trying to track down the culprit.
 

Alex1888

Active Member
Oct 26, 2020
62
21
The coolant temp sender in the block is a real pain to get to and change. I had mine done a few years ago and my mechanic said it was a right pain - he had to take out the airbox, pipework and other bits to get to it.

I fitted a new battery recently on my 2014 TDI as the older one would not charge above 60%. Certainly stopped the known long cranking issue.

Hope you get your issues fixed. If you Google `paracitic battery drain`, there are some useful pages on trying to track down the culprit.
Yeah I think I might get the garage to fit the coolant sensor.

My battery was 85 perce t when I checked it earlier so maybe not got a drain, will check in the morning.

Getting a few strange errors after a scan but I'm putting that down to new battery and the car being confused lol. One is driver side window regulator fault code. Done the resetting window 'trick' but error keeps coming back. Window works so no big deal. Electric issues are such a pain.

Cheers mate
 
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DEAN0

Old Git
Feb 1, 2006
5,297
305
Preston - UK
My battery was 85 perce t when I checked it earlier so maybe not got a drain, will check in the morning.

Yeah I think I might get the garage to fit the coolant sensor.

My battery was 85 perce t when I checked it earlier so maybe not got a drain, will check in the morning.

Getting a few strange errors after a scan but I'm putting that down to new battery and the car being confused lol. One is driver side window regulator fault code. Done the resetting window 'trick' but error keeps coming back. Window works so no big deal. Electric issues are such a pain.

Cheers mate
Do you have a battery charger/maintainer ?
Might be worth hooking it up overnite to see if it brings the battery up to 100%

Also - if that battery is not an exact replacement for the one that was on the car - it should be coded to the car so it knows what 100% is
 

Alex1888

Active Member
Oct 26, 2020
62
21
Do you have a battery charger/maintainer ?
Might be worth hooking it up overnite to see if it brings the battery up to 100%

Also - if that battery is not an exact replacement for the one that was on the car - it should be coded to the car so it knows what 100% is
I don't have a charger unfortunately.

Can I code it with Carista?
 

andylong

Active Member
Jan 21, 2021
489
1
129
If you have the same battery type and ah then coding won't be necessary as the specs will be the same.
Both of those things above will change the charge and discharge, and perceived state of charge, characteristics which nowadays cars care about.
 

andylong

Active Member
Jan 21, 2021
489
1
129
Your batteries state of charge will vary with temperature and age. Your car can only measure it's voltage, and decide on its state of charge from that, the relationship between those 2 things is affected by temperature, age and battery type.
Any load will reduce the battery voltage...it's very approximate.
 

BillyCool

Active Member
Jan 16, 2020
655
249
Leicestershire, UK
I don't have a charger unfortunately.

Can I code it with Carista?

Yes - you can change the code with Carista and tweak the Ah value if you need to. The car will then change it's charging settings. This is apparently advisable. You do not need a specific code - just change it by one digit.
 

SuperV8

Active Member
May 30, 2019
1,344
594
Brilliant info guys. Thanks I'll do that today
Also note - you have a 'smart' battery charging system - so it will probably never get to 100%! The battery management systems leaves some battery capacity in reserve to store excess energy when coasting down hill for example.
Also means using the volt meter to check the charging voltage is difficult as the charging voltage goes up and down depending in the battery management system requirement.
Your Carista should be able to monitor battery voltage. Over a journey should expect it to be going up and down.
 

Alex1888

Active Member
Oct 26, 2020
62
21
Also note - you have a 'smart' battery charging system - so it will probably never get to 100%! The battery management systems leaves some battery capacity in reserve to store excess energy when coasting down hill for example.
Also means using the volt meter to check the charging voltage is difficult as the charging voltage goes up and down depending in the battery management system requirement.
Your Carista should be able to monitor battery voltage. Over a journey should expect it to be going up and down.
Cheers mate. All good with the battery so far. Got a few different errors during last scan but putting it down to new battery. Things like my window regulator and some others. I think some things just need reset.

Main 2 errors still there though, coolant sensor and transmission selector sensor. Done a few long runs and car hasn't gone into limp mode and no warning lights. All my fuses are good as well. Will just have to keep monitoring it for now.

Thanks everyone for the help, much appreciated.
 
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SuperV8

Active Member
May 30, 2019
1,344
594
Cheers mate. All good with the battery so far. Got a few different errors during last scan but putting it down to new battery. Things like my window regulator and some others. I think some things just need reset.

Main 2 errors still there though, coolant sensor and transmission selector sensor. Done a few long runs and car hasn't gone into limp mode and no warning lights. All my fuses are good as well. Will just have to keep monitoring it for now.

Thanks everyone for the help, much appreciated.
Can you share the fault codes from Carista for the coolant sensor & transmission selector?
 

Alex1888

Active Member
Oct 26, 2020
62
21
Can you share the fault codes from Carista for the coolant sensor & transmission selector?
This is my latest results from Carista:

ABS:
08274
08330

Infotainment system:
02571 - Input for interior light dimmer

Central electronics:
00522 - Engine Coolant Temperature Sensor (G62)
00531 - Mass Air Flow Sensor Reference Voltage
262912

Driver's door:
65588


Obtained with Carista 7.4 for Android.
 

Alex1888

Active Member
Oct 26, 2020
62
21
The transmission selector sensor fault doesn't show on Carista app but shows on Car Scanner Pro
 

SuperV8

Active Member
May 30, 2019
1,344
594
This is my latest results from Carista:

ABS:
08274
08330

Infotainment system:
02571 - Input for interior light dimmer

Central electronics:
00522 - Engine Coolant Temperature Sensor (G62)
00531 - Mass Air Flow Sensor Reference Voltage
262912

Driver's door:
65588


Obtained with Carista 7.4 for Android.
Regarding this fault code:
00522 - Engine Coolant Temperature Sensor (G62)

Are you handy with a DVM?

1: check the temperature sensor supply voltage.
Disconnect the coolant temperature sensor.
Turn the ignition on.
Measure the voltage on pin 1 in the female connector. Is it between 4.8 and 5.2 V?
If YES - move onto 2:
If NO - Turn the ignition on. Do not reconnect the coolant temperature sensor. Measure the voltage on pin B 38 (E1 Engine control unit). Is it between 4.8 and 5.2 V?
If YES - Measure the resistance between pins 1 and B 38 (E1 Engine control unit). The resistance should be less than 1 ohm. Check all wires; renew if
necessary. See the diagram below for details on wire colours/codes, connectors, welds and locations (if applicable).
If NO - Check the following: E1 Engine control unit. Attention! If no faults are detected during the diagnostic check, the control unit may be internally faulty.

2: Check the temperature sensor ground (pin 2).
Turn the ignition on. Measure the voltage on pin 2. Is it between 0 and 0.2 V?
If yes - This test has been completed successfully.
If No - Turn the ignition on. Measure the voltage on pin 1 (O8 Grounding point 486). Is it between 0 and 0.2 V?
If YES - Measure the resistance between pins 2 and 1 (O8 Grounding point 486). The resistance should be less than 1 ohm. Check all wires; renew if necessary.
If NO - Check the following: O8 Grounding point 486.
 

Alex1888

Active Member
Oct 26, 2020
62
21
Regarding this fault code:
00522 - Engine Coolant Temperature Sensor (G62)

Are you handy with a DVM?

1: check the temperature sensor supply voltage.
Disconnect the coolant temperature sensor.
Turn the ignition on.
Measure the voltage on pin 1 in the female connector. Is it between 4.8 and 5.2 V?
If YES - move onto 2:
If NO - Turn the ignition on. Do not reconnect the coolant temperature sensor. Measure the voltage on pin B 38 (E1 Engine control unit). Is it between 4.8 and 5.2 V?
If YES - Measure the resistance between pins 1 and B 38 (E1 Engine control unit). The resistance should be less than 1 ohm. Check all wires; renew if
necessary. See the diagram below for details on wire colours/codes, connectors, welds and locations (if applicable).
If NO - Check the following: E1 Engine control unit. Attention! If no faults are detected during the diagnostic check, the control unit may be internally faulty.

2: Check the temperature sensor ground (pin 2).
Turn the ignition on. Measure the voltage on pin 2. Is it between 0 and 0.2 V?
If yes - This test has been completed successfully.
If No - Turn the ignition on. Measure the voltage on pin 1 (O8 Grounding point 486). Is it between 0 and 0.2 V?
If YES - Measure the resistance between pins 2 and 1 (O8 Grounding point 486). The resistance should be less than 1 ohm. Check all wires; renew if necessary.
If NO - Check the following: O8 Grounding point 486.
Thanks, if I can get to the sensor I'll try that. There's not much space to get in to it.
 

SuperV8

Active Member
May 30, 2019
1,344
594
Thanks, if I can get to the sensor I'll try that. There's not much space to get in to it.
Basically with the ignition on, 1 pin on the coolant temperature sensor connector should have 5v and the other pin should be 0v, reference to ground.
If this checks out, it's probably a new coolant sensor.
If this is not the case - you are into checking wiring/ECU/grounding.
 
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