Faulty fan or J293?

[a4_jim]

Please help.....

Pulled the two below codes from my car which drives likes its in limp mode.

18339 - Coolant Fan Control Module (J293): Malfunction
P1931 - 004 - No Signal/Communication - Intermittent

17522 - Oxygen (Lambda) Sensor; B1 S2: Internal Resistance too High
P1114 - 008 - Implausible Signal - Intermittent

I've checked both fans and they spin at low speeds thus my water temp was over 100c. I believe the J293 is a possible cause but this part is pretty expensive. I checked both fans could spin freely by hand but noticed the main 600w was squeaking, possibly carbon bushes are worn.

Question is could a faulty fan throw a malfunction code from the J293? If the carbon brushes are worn the fan will sooner or later burn out. The J293 would read this as a faulty module correct?

Not driven the car since and considering to replace the main fan before the J293 fan control module. Other symptoms I have is the A/C not being cool. So do I have a fan that is dying plus a dying J293 module?

Is the second code caused by higher than normal temps from the exhaust gases?

Thanks!

J

[a4_jim]

Bump....anyone?

Thanks

J

[andythechief]

Hi- I have a similar fault on my 53 plate 1.8T A4. From what I have read, yes a fault code will be registered if the fan motor is starting to fail / failed but also if the control module is failing too. On my car, the fan failing caused an 'intermittant- lower limit exceeded' fault as opposed to your 'no signal'

My car has the two fan arrangement and air con. The main fan works fine but the smaller appears to have failed completely. On the basis my aircon works fine and yes you are correct, the aircon does turn the larger fan on (as does elevated coolant temp), I would say your larger fan/module is the problem.

I would suggest the second error code has nothing to do with the first. A dangerous assumption as they are often related but nevertheless, I have had to replace my mapped control thermostat and one fan has failed and I have not had any faults on the exhaust. I also logged temperature readings before and after the work to date and have managed to reduce the engine coolant temperature slightly. Hopefully a little more soon....

I see my J293 has been replaced already given it is dated 2006. What I am completely unable to ascertain is how to test the outputs to the fans. Both are variable speed (I think) and are supplied by two wires- presumbly then they are given a variable DC voltage? If we are able to get these voltages, both of us could obtain an answer very quickly.

FYI- genuine J293 retails at £130 and smaller fan also £130.

Not a complete answer, but perhaps contributes to fixing something that may unfortunately become quite common.

Andy

edit- just been out and tested the outputs from the J293. The voltages between the two pairs of output cables were both 4.8V DC. I should say that to test the voltages, I had started the car, switched the aircon on (to activate the fans) and tested the voltages. So the car was not at a running temperature and I make the assumption that aircon always switches on both fans at the same speed and therefore voltage. With a running temperature I think it likely the voltage would be higher. So in my case, with the large fan running and the smaller not, I can only conclude my smaller fan has failed.

To get at the terminals on the J293 you will need to pull off its plastic cover- which breaks slightly but will clip back on ok. Once removed, be careful not to pull the cables/terminals, they are quite weak.