32 minutes ago, Tech1e said:

 

Fabia 1 is pre CAN for diagnostics. The CAN network is fairly basic and used mainly for comminucation between control units and gateway.

 

Just unplug the stereo (if aftermarket) and see if it comes back up.

It is the one that came with the car but not working. Maybe due to physical cable disconnection behind it or other reason.

Dear Wino & Techie I got good news from your guides.

 

So I got down this afternoon to confirm that EPU pin 43 was not continuous with Diag connector Pin 7 and we promptly swapped similar white/grey cables from the ECU connector going down the wiring loom.

 

Then we discovered the brown connector on thermoswitch 3-pin connector was broken at the connector head so we got another used one as replacement.  We could not find continuity between ECU T81/11 any of the wires in the 6-pin connector of Radiator fan control module.

 

We checked the outcome of our efforts so far and found out happily that we could now query the ECM from VCDS and if we allow the coolant temperature rise to about 95 degrees the radiator fan turns on and off for a few seconds and at most about 90 seconds.

 

So Iwant to thank you for the success achieved based on initial faults reported.

 

Then we noticed the instrument cluster temperature indicator always stop at 80 degrees even when coolant temperature as measured with VCDS goes as high as 95-98 degrees. At a point we also saw the catalyst container end that is away from the exhaust manifold glowing red hot!

 

What could be responsible for delay in fan turning on and the temperature gauge getting stuck at 80 degrees mark?

 

7 minutes ago, FemiE said:

We could not find continuity between ECU T81/11 any of the wires in the 6-pin connector of Radiator fan control module.

 

Can you explain why you think there should be a connection there?

 

I think that 6-way connector should have two connections to the radiator thermoswitch, two connections to the HVAC module, an ignition switched 12 volt and a permanent 12 volt.

Here's a rather rough sketch I've made of the circuit inside the fan control module:

 

Hi Wino, I saw a diagram online somewhere perhaps it is not for my engine code,

 

I will follow your schematic above.

Try shorting out the connections between the brown wire and each of the other two in the thermoswitch loom connector (with ignition on) to test whether both low speed (stage 1) and high speed (stage 2) relays are switching and causing the low and high speed running of the fan. Did you check the fuses I suggested in the fuseholder above the battery?

 

Failure of the low speed fan operation is common, due to the internal resistor breaking. Maybe your fan is only working at high speed?

 

You can download all the circuits for mk1 Fabias for a 7 Euro + tax fee at erWin Skoda, which is probably worthwhile for you.  I can help you to navigate that site to get the best value out of your 7 Euros if you want?

 

I'm not sure why your temperature gauge is showing a lower temperature than VCDS is seeing, is it possible that someone has taken the clocks apart and re-fitted the needle at the wrong angle?

1 hour ago, Wino said:

Try shorting out the connections between the brown wire and each of the other two in the thermoswitch loom connector (with ignition on) to test whether both low speed (stage 1) and high speed (stage 2) relays are switching and causing the low and high speed running of the fan. Did you check the fuses I suggested in the fuseholder above the battery?

 

Failure of the low speed fan operation is common, due to the internal resistor breaking. Maybe your fan is only working at high speed?

 

You can download all the circuits for mk1 Fabias for a 7 Euro + tax fee at erWin Skoda, which is probably worthwhile for you.  I can help you to navigate that site to get the best value out of your 7 Euros if you want?

 

I'm not sure why your temperature gauge is showing a lower temperature than VCDS is seeing, is it possible that someone has taken the clocks apart and re-fitted the needle at the wrong angle?

Yes I confirmed both fuses on the battery casing at pin 3 and pin 8 are intact.

 

I really need to confirm if the single fan is turning on at low speed or high speed before turning for the brief period the fan works.

 

I will check which of the relays works but I must mention I do not get any fan relay fault code in VCDS but when I disconnected the 6-pin connected on the fan module I got codes for both stage 1 and stage 2 relays open or short to plus.

 

I have tested the fan directly from the battery and confirned the fan works at high speed by connecting pin 1 and pin 3 cables to the battery. Is it safe to do the same with pins 2 and 3 to confirm fan low speed operation directly?

 

I can only do more checks tomorrow while I do more research tonight.

 

I appreciate if I can get good documentation on Fabias and Octavias made between 2002 and 2009 for a small fee.

 

Cheers.

15 minutes ago, FemiE said:

Yes I confirmed both fuses on the battery casing at pin 3 and pin 8 are intact.

 

I really need to confirm if the single fan is turning on at low speed or high speed before turning for the brief period the fan works.

 

I will check which of the relays works but I must mention I do not get any fan relay fault code in VCDS but when I disconnected the 6-pin connected on the fan module I got codes for both stage 1 and stage 2 relays open or short to plus.

 

I have tested the fan directly from the battery and confirned the fan works at high speed by connecting pin 1 and pin 3 cables to the battery. Is it safe to do the same with pins 2 and 3 to confirm fan low speed operation directly?

 

I can only do more checks tomorrow while I do more research tonight.

 

I appreciate if I can get good documentation on Fabias and Octavias made between 2002 and 2009 for a small fee.

 

Cheers.

In addition I want to confirm if by shorting you mean I should bridge the brown wire with the brown/blue and brown/green wires in turn with ignition on to confirm low speed and high speed fan operations.

9 hours ago, FemiE said:

In addition I want to confirm if by shorting you mean I should bridge the brown wire with the brown/blue and brown/green wires in turn with ignition on to confirm low speed and high speed fan operations.

Yes, exactly. 

With your brown wire previously broken, the radiator dual thermoswich would have been unable to make the fan spin whatever the coolant temperature was. Only other trigger is refrigerant pressure via G65 sensor and HVAC module as far as I understand.

 

I'm not sure if excessive coolant temperature seen via CAN comms can make the HVAC module spin the radiator fan. 

10 hours ago, FemiE said:

I have tested the fan directly from the battery and confirned the fan works at high speed by connecting pin 1 and pin 3 cables to the battery. Is it safe to do the same with pins 2 and 3 to confirm fan low speed operation directly?

Yes.

2 hours ago, Wino said:

Yes, exactly. 

With your brown wire previously broken, the radiator dual thermoswich would have been unable to make the fan spin whatever the coolant temperature was. Only other trigger is refrigerant pressure via G65 sensor and HVAC module as far as I understand.

 

I'm not sure if excessive coolant temperature seen via CAN comms can make the HVAC module spin the radiator fan. 

I will carry out the procedures today and give an update later in the day.

 

Thank you.

Hi Wino.

I finally got around to test Fan stage1 and stage2 operations today and both were successful.

 

The fan control module was switching on stage1 cooling at about 95 degrees and stage2 cooling only when I turn on the airconditioner and coolant pressure rises to about 14.5 bar.

 

I want to say thanks for all the support and the success achieved.

It was a pleasure helping you.

 

My experience of the refrigerant pressure triggered fan operation is that even with cold engine, if refrigerant pressure gets to 9 bar the fan(s) start at low speed, and if/when 16 bar refrigerant pressure occurs, the fan(s) go to high speed.  High speed switches off at 12 bar, and low speed at 6.3 bar if my memory is correct. I have some VCDS log graphs somewhere.

Both our cars have two fans, and on both the smaller fan is single speed, coming on with the low speed of the main fan.

Edited 18 October, 20187 yr by Wino