03P (CFWA) radiator fan control unit J293 coding discovered



Verified VCDS User
Aug 10, 2016
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Eindhoven, NB, NL
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Dear all,

I have made a discovery, using some trial-and-error and confirmed:

Address 01: Engine (J000-CFWA)       Labels:. 03P-906-021-CFW.clb
   Part No SW: 03P 906 021 B    HW: 03P 907 425 
   Component: R3 1.2l TDI   H06 9980  
   Revision: 12005001    Serial number:               
   Coding: 00114036013400080000
   Shop #: WSC 31889 470 31889
   ASAM Dataset: EV_ECM12TDI03103P906021B 001043
   ROD: EV_ECM12TDI03103P906021AA.rod
   VCID: 270B06DDAF6FF1F3EE9-8073

This is the ECU for the 1.2 TDI CFWA engine with start/stop PR-7L6

The J293 is located, from factory, in the heart of the radiator fan and is operated via a single PWM wire by the J623 engine control unit.


Now there is also a radiator fan with 2 fans for the high-powered cars like the GTI and the R (1.4 TSI 132 kW and 2.0 TSI 165 kW).
This is operated in the same way.

There is also a radiator fan, that is not operated by the ECU but by the radiator outlet temperature sender and the climate control panel.
This is found in all cars without start/stop (PR-7L3).


T6ab/5 and /6 go to the climatronic panel, /2 is a +15.

Now, if these two were to combined in, let's say, a car with a 7L6 ECU and a 7L3 fan, the ECU will happily complain that the radiator fan is not connected and therefore will block the operation of the A/C compressor.
I found out the hard way.

But happily, there is a coding solution!
I found it, it's not labeled yet, but perhaps Ross Tech can do this.

ECU 03P 906 021 B (so 7L6!)

Byte 4 bits 0, 1 and 2:
01 (BIN 001) one switched fan installed via external J239 relay
03 (BIN 011) one continuous fan installed via PWM T94/90
04 (BIN 100) two continuous fans installed via PWM T94/90 like Polo 6R GTI/R WRC

I suspect that 02 might 'trigger' two switched fans but am unable to verify.