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Discussion Starter #1
Hi All

As mentioned in my introduction thread my recently acquired Alfa has it’s engine management light on.
It’s a 156 Sportwagon Veloce with the 1.9 16V JTD Engine.

I brought it knowing the Engine Management light was on, and a message on the info screen reads Engine Control system failure, or something very similar.

The guy I brought it from has conned me a little, I took his word for it that he’d read the codes, and it was the EGR valve that was the issue. This was backed up by the fact that for the last few months all he’d done was drive the car up and down his road once every two weeks to warm it up.

Sure enough on the drive home I gave it a ‘bit of a thrash’ and was rewarded at first with lots of smoke when pulling away.
This stopped very quickly, and over the last few days it’s not smoked at all, drives very nicely and performs well.

As all my Code Reading equipment was Land Rover Specific I ordered myself a Foxwell NT301 Code reader, believing all would be well once I’d read and cleared the fault codes.

The Foxwell arrived yesterday and I plugged it in.
Considering I’ve been enjoying the car ‘enthusiastically’ for a few days, I was pleased really that there was only one fault code showing – P0481, relating to Fan 2 control system. But annoyed it wasn’t the EGR Valve.

it’s performed very well, and not appeared to get too hot by the gauge, despite our recent very hot weather.

Having spent some time searching on this great forum I’ve tried some fixes already, but the code pops up instantly again after being cleared along with the message and Engine management light.

My initial fault finding wasn’t helped by the Relays under the bonnet not matching their cover or the image in the owners manual. As can be seen from the image below I have a different layout of Relays and one 30A fuse to the cover, and no, the cover doesn’t fit properly, but I have established that on the Top row from Left to right the black relays are:

Fan 1 High speed – Fan 1 Low speed – Fan 2

Using a link wire to bridge the power feed on the Fan 2 Relay base the fan runs, so it’s not the fan itself.

I’ve tested the Fan 2 Relay on my bench and it switches OK.

I’ve swapped the Relay in the Fan 2 position with both of the Fan 1 relays and the fault stays the same, so I’m assuming the relay is not at fault.

The car came with some spares, including a used temperature sender which screws into the Thermostat housing.
The one in the car appears brand new, suggesting the owner swapped out the sender and it didn’t fix the issue.

I’ve disconnected and cleaned up all four of the connectors that appear to plug into sensors in the radiator, two at the top and two at the bottom.

The fault code still pops up though.

Does anyone have any suggestions what I should be looking at next?

Thanks

Nasher.
 

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Discussion Starter #3
Thanks Fruity.
I'll have a good read through your thread.

The AirCon works fine, nice and cold, which surprised me, you don't expect a 15yr old used car that looks a bit rough to have gas in the Aircon.

How would that be connected to the Radiator Fan 2 issue?

The code P0481 is quite specific for Radiator Fan 2, my Foxwell suggests it's the relay or a short in the fan, both of which I think I've eliminated.

Nasher.
 

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The engine ECM switches the relay for the fan high speed. Wires come from ECM, go to relay and back to ECM.

I'm not sure how the ECM monitors the circuit. It must be voltage or continuity (resistance) and it must be monitored all the time.

If you have a false fault code, I suggest careful checking of the terminals and wires. When a terminal is fitted to a wire, the metal strands are unprotected and this allows oxidation /corrosion into the wire. That being the case, then both the terminal and part of the wire need replacement.

This sort of fault is becoming very common and it is a sure sign of deterioration. In order to repair correctly, people need to get terminals for housings (with retaining tabs) and the correct crimping pliers for OE type terminals (not the amateur red/blue/yellow plastic covered connectors).

Unfortunately Alfas do tend to have certain critical wiring/terminals unprotected and the environment influences the oxidation. Just look at the wires and terminals and even the relays in front of the battery. Fit new terminals/wires as necessary and protect with an anti corrosion spray such as ACF-50. It would be better to take early action to avoid phantom faults but hardly any one will because this idea of unprotected monitored circuits is quite new and it will likely take a few years before it is realised that this is something to be expected (to some degree) in older cars.
 

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Discussion Starter #5
Thanks Fruity.

I sort of knew I'd just need to start going through connectors, I was just hoping somebody would point me in the right direction of exactly where to try first.

Crimps and cables are well known to me, but a bit smaller, I work in Aviation Electronics, but of course none of that is allowed to be so exposed in something like an engine bay.

Are both Fans two-speed?
From what I can tell only Fan 1 is two-speed not the Fan 2 I have the problem with.

Oh well, wish me luck.

Nasher
 

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....
Are both Fans two-speed?
From what I can tell only Fan 1 is two-speed not the Fan 2 I have the problem with.

Oh well, wish me luck.

Nasher
The fans are not really 2-speed. For the low speed, a series resistor is simply switched into the powerfeed of the Fan
(O10 & O12 in the diagram)

Also note the 156 uses 2 temp sensors, one for the ECU, that is used for control of fans and engine management, and a seperate one for the temp.gauge.
Sensor(s) are NTC, and in later model cars both NTC sensors are placed in the same screw-in housing, so at first glance look like a single sensor, but electrical connections show connections for both sensors.

For additional info, see attachments :
 

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Discussion Starter #8
jwq, many thanks, that's great info, the wiring diagram will really help.

So I can see now that for Low speed operation both fans are activated by a signal from Pin 90 on the ECU to a single Relay J30 which switches the Earth for both Fans which is then 'restricted' by Resistors O10 and O12.

For High Speed operation both fans are activated by a signal from Pin 69 on the ECU to individual Relays for each Fan J31 and J32, which again obviously switch the Earth to the Fans but without the resistors.

So it appears that there should not be a case where Fan 1 should Run without Fan 2.

I can really narrow down my search for a bad connection or component now, but it looks like I could narrow it far more if I could establish exactly which Fans are running at Low and High Speed.

For example if Fan 1 runs at both speeds I can eliminate sensors, an ECU fault etc and just concentrate on Fan 2 wiring and connectors etc.

At the moment if I open the bonnet with the car hot Fan 2 is off but Fan 1 is on, but I honestly couldn't say if it's running fast or Slow.
My guess is that Fan 1 is running slow and fast, but Fan two only running Slow.

A daft question really, but at what times should the fans run Slow and Fast?
I could be wrong, but I'd suggest that at rest, slow road speed, or just after turning the ignition off the Fans will run Fast. And at faster road speeds the fans will run slow.
So I'm not sure how I'll test if Fan two runs at slow speed whilst travelling at higher Road Speeds - If that makes sense.

Interestingly at no point when I bridged the 30/87 Terminals on the relays did both fans run at once. So this suggests my problem is O12. But that is contary to what I think above.

Nasher.
 

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Discussion Starter #9
Sorry, one more question.

What do the Resistors look like? and where are they located in the engine bay?

Thanks

Nasher
 

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Where abouts are you? It's easier to use a diagnostic tool to manually activate the fans and find out where the fault it. May be someone nearby with the kit who can lend a hand.
 

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So when you link 30-87 on j30 did just one fan run?
Also fan speeds are controlled by ECU based on temp sensor feedback.
Have you bridged 30-87 on J31 and 32 to test individual fans at high speeds?
 

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Discussion Starter #12
Lukew hi.

I'm down on the South Coast of the UK, North Of Portsmouth, between Waterlooville and Petersfield.

Nasher.
 

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Sorry, one more question.

What do the Resistors look like? and where are they located in the engine bay?

Thanks

Nasher
Afaik, the resistor(s) are mounted on the radiator, they're quite large so hard to miss. You should be able to find them tracing back the wire from the Fan connector ;)
The 2 fans should work as one, so both behave in parallel
Low speed is when airco is on, or when engine temperature reaches first tripping point. 2nd (hi) speed is engine temp 2nd tripping point.
On petrol engines this is:
lo: 95 degr
hi: 102 degr



I would think it's the same on the diesel
 

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If when you bridged the relays, both fans didn't run at once, I'm sure you will know that this suggests the resistor/terminals/wiring is the fault (assuming you had bridged/activated the relay for low speed and nothing happened).

You will probably also realise the output side of the relays is not monitored so any fault indicated by diagnostic trouble codes indicate issues from ECM to relay and back to ECM.

Note that the 2 high speed fans have terminals 85 & 86 swapped. It looks like you already have a suspicion about the pin 69 wiring (LR) but don't forget wire (RV either). I think you'll have this one wrapped up quickly.
 

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Discussion Starter #15
Thanks Guys, I'm far better prepared to have a look at it now, just need to get myself a spare hour or so to do it.

I'll report back later

Nasher.
 

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Update

I noticed late yesterday when I stopped the car and opened the bonnet that only one fan was running, the temp gauge inside the car was showing @100, and the fan looked to be running at slow speed.

So this morning I decided my best course of action was to look at the Resistors.

They both looked OK at first glance, but when I tested them with a Multimeter I discovered one was completely open circuit, and when I investigated I found that one of the Tangs from the tube had broken free of the track connecting it to the blade the wire connects to, and whilst I was prodding it, and wondering what to do next, the other end broke off.

I called both my Local Alfa dealers, 3/4hr in two different directions.
They both insisted that my car having given them the reg number only has one resistor not two.
I checked they were not looking at the internal heating fan resistor pack, and they both confirmed they were looking at a resistor attached to the radiator cowling, and again insisted my car only has one, and it would be £138!!!

One suggested my problem was that somebody had fitted the wrong radiator to my car, but didn’t reply when I pointed out that there was wiring for two resistors!

Anyway, that put paid to me finding new resistors today, but I’ve ordered two from EBAY for @£20ea.

I cleaned up the parts of the broken resistor and soldered it back together, adding a small cable tie through the tube and plastic body to remove any stress on the soldered joints.

When plugged back in I was pleased that when I bridged Relay J30 both fans ran at low speed.

Thinking I’d sorted it, I cleared the codes, but the P0481 popped straight back up again. – Bugger.

Back into fault finding mode, I now found that when I bridged either J31 or J32 both fans ran, not just one.
Looking at the wiring diagram I can only assume that the ‘other’ fan is being powered through both resistors.
For example, if I bridge J31 across 30 & 87,N12 is connected directly to earth, but N11 is also connected to Earth through O10 and O12.
Looking again at the Resistors, I’d assumed the resistance was in the green tube(Wire Windings) and that the large ‘Through Hole type components were Diodes to stop exactly the above happening, but apparently not.

Or, perhaps the Diodes are no longer doing their job, and the increased resistance showing is what’s causing my fault code, I’ll find out when my new resistors arrive.

To ensure that I had everything correct I unwrapped quite a bit of the loom, and traced the wires comparing them to the diagram, making notes of the cable colours as I went.
This through up some strange cable choices, such as the power Cables to J32 30 & 87 being a much much heavier gauge wire than anything else, and the Red one being split by the big 3 way connector just in front of the engine bay relay box. Which makes absolutely no sense at all.

The only wires I didn’t trace all the way through were the two signal wires back to the ECU, but it will be next weekend before I have time to do that now.

Taking the car out for a run this afternoon it certainly ran cooler, @90 -95 rather than the 100-105 it has been running at.

So I think I can say the despite the P0481 code the slow speed circuit is at least working.
I don’t know if the High speed circuit is working as the engine didn’t get hot enough.

I’m really interested in your comment Fruity that the output side of the relays is not monitored,so any fault indicated by diagnostic trouble codes indicate issues from ECM to relay and back to ECM. I’m assuming all the system can ‘see’ is a difference in Resistance.
I’m assuming the RV wire is OK as I have a good clean 12V at 85 on J32

To test the High Speed circuit, all I can think to do is trace the LR wire back to the ECU, snip it a few inches away and ground it to see if the fans start up.

My other option from reading on here would appear to be a faulty Temp sender, but the one in the car is almost new.
Is the relevant sender the one screwed into the thermostat housing?

Any more suggestions would be really appreciated.

Thanks

Nasher.
 

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Discussion Starter #17
Sorry, need to ensure I've ordered the right resistors.

The ones in my car have Black plastic bases, and I'm sure are marked 0.18 Ohm

Yet here:
https://www.alfaworkshop.co.uk/parts/Alfa_Radiator_fan.shtml

It looks like my 2004 156 Sportwagon fitted with a 1.9 16V JTD with aircon should have the Red base 0.23 Ohm resistors.

Can somebody confirm please?

I suppose it could have been fitted with incorrect resistors in the past, and I assume it will just effect the actual speed of the low speed running, but could it effect the Aircon and throw up my P0481 fault code?

Nasher.
 

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to test the high speed, it would probably be sufficient to pull the plug on the temperature sensor. This will throw up an error to the ECU, causing it to go into failsafe mode, meaning the fans will run at full speed.....

I appeciate you just bought the Foxwell tester, however, for regular faultfinding MES (http://www.multiecuscan.net/ ) might have been better, as this allows you to switch the different devices (such as fans ;) ) and translate the specific alfa faultcodes, together with possible causes....Not helpfull, I know ;)
 

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re the resistor, you could probably check on one of the eper sites (example: FIAT ePER ) and put in the VIN of your car. This will give you the parts for your specific model.
Of course an Alfa dealer could also do this ;)

If you send me your VIN, I could also see what my copy of eper says...
I had a quick look, and there seem to be multiple configurations....
example:
 

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