The Heirloom Laguna Deux

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SiC
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Re: The Heirloom Laguna Deux

Post by SiC » Sun Sep 22, 2019 11:48 pm

Pulled the beasty out this morning and put the Boxster away.
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Tyres weren't completely flat this time. However they are very badly flatspotted. Pumped the fronts up to the max motorway/towing pressure to try getting them to round off a bit. Going to have to bite the bullet and get the fronts at least replaced.

Put a second hand Sat Nav CD unit in
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Screen came alive but it wouldn't talk to the button control unit. The buttons just flashed on and off - apparently means incompatible. FFS

So pulled out the button unit. Couldn't find my radio keys, so used the next best* thing
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Got a replacement unit that apparently is a matching part code. Hope it works as this will start getting expensive.
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While I was in the glovebox I thought I should check the pollen filter.
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Almost full Northampton Renault Dealer service history on this car. FFS

Looking at the aux belt, I think it's going to need that changing soon as it's very cracked. Also I have no idea if/when the cambelt was done, so that'll have to be on the high priority list.

I'll give my local garage a call and see how much they want for all to be done. Both belts + tensioners + water pump. Probably leave the dephaser and take the risk on it (which I'll probably regret...)
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Re: The Heirloom Laguna Deux

Post by ghosty » Mon Sep 23, 2019 2:24 am

Fucked filters are no surprise on a dealer service history. On my aunt's old Fiesta now with a family friend, the air filter wasn't even a service item on the dealer service list, let alone something on the list and ignored.
Watch for pedestrians...
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Re: The Heirloom Laguna Deux

Post by SiC » Sat Sep 28, 2019 11:37 pm

Started using the Laguna this week. This morning it struggled to start as I put a way too small battery in it. Upon starting it decided to stop reading the fuel level and the posh lady moaned there was no fuel. After a minute it decided it did want to start reading the fuel level again. 
 
Anyway went off into town as I need to go to work this morning. Afterwards I went off to get a few bits and pieces - including a new battery.
 
New battery fitted and it starts much better. Except on a drive the posh lady told me that my right brake light was faulty. Checking them and they were fine? Restarting the car cleared the warning.
 
Also found out today with this heavy rain that it has automatic wipers. However there is no way of adjusting the sensitivity of this? Usually I've known an adjuster. Did the early ones not have this? I know my wife had a 52 plate Clio II with auto wipers and that had adjustable sensitive. Maybe the factory fitted the wrong stalk on the Laguna...
 
Earlier this week I plugged in a second hand Satnav CD reader to try getting the screen alive again.
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This it did but the control button unit isn't compatible with it. Turns out you need to get an almost exact match part numbered pair. Go figure.
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Got one that some random internet post said was correct and fitted it. Now the satnav came alive fully and so I could use the radio
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Unfortunately the new CD unit wouldn't read the disc. Actually it didn't even spin the disc. Pulled the unit apart and swapped in the old units CD reader
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Now it just spits the disc out every time. Kinda given up trying to get the satnav bit working now. At least I have the radio, time and outside temperature back again.
 
While I was replacing the cd drive, I also replaced the pollen filter
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I think I'm going to have to replace the cambelt for sure. Don't like driving it with a aged belt and it's giving me anxiety when driving that it may snap suddenly. The cracked aux belt doesn't give confidence that the cambelt will be in sparkling condition.
 
No one can remember if the cambelt has ever been changed. Our best guess is no, as we think we didn't on the basis that if it snapped, it would have been a useful way to get my grandad to give up driving.
 
One final thing I've noticed is that the climate control has two modes. Fully minimum temperature on it gives cold. Any temperature above that gives full heat. I can hear the flaps moving and you can hear them going to the full extent on both sides. Pretty sure it's the cabin temperature sensor that is on the blink.
 
Tried cleaning it and removing any dust but it made no difference.
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Got to love early 2000 Reno...
 
 
#LagunaLife
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Re: The Heirloom Laguna Deux

Post by Hooli » Sun Sep 29, 2019 12:42 am

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Re: The Heirloom Laguna Deux

Post by AutoshiteBoy » Sun Sep 29, 2019 11:04 am

Whats the date on the non-genuine cabin filter?
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Re: The Heirloom Laguna Deux

Post by SiC » Sat Oct 12, 2019 11:52 pm

On Monday this is booked in for some major fettling. Cambelt, aux belt, tensioners, water pump and thermostat. Part of my investment into this to make sure it lasts a long time. Always risky giving a Laguna too much attention though.

In the meantime, I decided to change the plugs today. Cheap enough and I have no idea when they were last done. Idle is a tad unstable too.

Bonnet up
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Tiny little engine cover off
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Coil plugs off. Plastic tube covering the wires is very brittle at this age
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Coils out
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Plugs out
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Look a decent colour. Gotta love fuel injection to keep things running sweet. We really do take it for granted nowadays
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Electrode is pretty worn though. Main dealer service history on this
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Coils are a known weak point around this age. They are original too (Week 26, 2002)
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Denso though
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Obviously being of Japanese manufacturer, they are of good quality. Sagem were the troublesome ones according to Renault
//cloud.tapatalk.com/s/5da2547c20c6f/4242A.pdf

Next up is the climate control. It seems to have two modes. Minimum temperature (16c indicated) gives full cold. One notch above (16.5c) it gives full hot. The engine coolant thermostat is broken at the moment so that's bareable. However once Mondays work is done, it's going to get very unpleasant. So I decided to have a look.

A common issue with these is either the exterior temperature sensor or the interior sensor. Exterior is fine as it's reading a realistic 11 celicus on the big screen. Interior I did some diagnosis.

It lives up behind the rear view mirror
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The blue bead is the temperature sensor and the white cylindrical object is a humidity sensor. There is a little fan behind which forces air over this


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Getting it apart required judicial force to prise the middle
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Which after some delicate bending, got it split
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Quite a simple circuit. Solder joints look good. Material coating is conformance coating, this prevents corrosion
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Checking the temperature sensor with a Multimeter gave sensible values. A common type is 10k ohms at 25c. Breathing over it brings the resistance down to around 7k. This corresponds to roughly 35c. Quite acceptable
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So I had a check of the climate control panel. Like most Renaults of this era, it's mostly held together with plastic tabs. Pulling the card reader out required no screws removed. Climate panel had two plastic to be gently bent and the panel pivoted out.

Top side looked good
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Bottom panel looked all good too
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Hmmmm


Some more Googling found that there is three temperature sensors in this system. Exterior, interior and a evaporator temperature sensor. Interesting!

Now I wouldn't have immediately thought the evaporator sensor would be a problem as it goes to these extremes with the Aircon off. Either way I thought I'd have a look.

The sensor lives in the passenger footwell behind a plastic kick panel. A twist and a pull was all it took to remove. Then the connector gently pulled back to disconnect.
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So did it do anything? You bet it did! With it disconnected, I can hear the mixer flaps progressively move now as I turn the temperature up. Running around the block seems to show it works properly now!

Only on a Renault can you properly fix electrical problems by disconnecting and removing things... :D

I'll probably get another one as when I've got the Aircon regassed, the system will need it to properly regulate the temperature. I believe the evaporator must never go below freezing point otherwise things don't work properly. So in cold weather especially, this sensor should stop that happening.

Probably be a dealer part if they still do it. They're getting of the age now that Renault is stopping parts support. eBay doesn't bring up much either, apart from a few international sellers or some manky and expensive UK breakers.
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Re: The Heirloom Laguna Deux

Post by SiC » Sat Oct 12, 2019 11:53 pm

AutoshiteBoy wrote:
Sun Sep 29, 2019 11:04 am
Whats the date on the non-genuine cabin filter?
Dunno, I chucked it straight out. Don't think it had one on it though. Certainly not noticeably.
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Re: The Heirloom Laguna Deux

Post by fried onions » Sun Oct 13, 2019 8:08 pm

All these extravagant electronics. I'll stick with basic old cars. And still modern traffic can't keep up with me.
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Re: The Heirloom Laguna Deux

Post by AutoshiteBoy » Sun Oct 13, 2019 8:32 pm

Clever diagnostic work.
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Re: The Heirloom Laguna Deux

Post by SiC » Sun Oct 13, 2019 9:58 pm

fried onions wrote:
Sun Oct 13, 2019 8:08 pm
All these extravagant electronics. I'll stick with basic old cars. And still modern traffic can't keep up with me.
They aren't necessarily more complex than an older car, just a bit different! Fault finding isn't really too different really - the good old fashioned process of elimination and some intuition. Just the tools you use to do it and the process is slightly different as it's more electrical than mechanical. My belief is very much that something is only complex if you don't yet understand how and why it works.

This generation of cars are fairly rudimentary really. For instance this climate control is a basic input, process and output system. Inputs are exterior, interior and evaporator temperature sensor, humidity sun sensor and user controls. Outputs are driver & passenger temperature mix flaps, air direction flaps, recirculation flap, blower motor and a/c relay. On an old car, you still have those flaps, fan speed and heat control (flap or valve) but as the processing is done by a human they don't move by themselves. A scan tool is what allows you to move those automatic climate controls by yourself in a similar way and what it thinks the inputs coming in are.

For example, if the drivers side is stuck hot, what do you do on climate? Try setting it to cold on both sides. Still hot on just drivers side? Check the flap motor is moving. If it is, then the flap is most likely broken. If not then remove flap motor and check it turns on the bench by powering the motor or use the diagnostic tool to do so. Use a multimeter to check the climate unit is sending a signal.

I knew the flap motors were working on this Laguna as I could hear them move and hit the end stops. So I could twiddle the controls and listen to how they reacted. Also putting my finger on the back of the control motors allowed me to check that what I was hearing is what I thought was moving. As both sides were moving to similar positions, I knew it must be an input problem. Sun strength is only used to tweak the temperature, so I knew that wouldn't cause it to move to the end stops on small temperature settings. Exterior was reading fine on the big display. As that gets send over the CAN network, it would be the same as what the climate is getting. Interior temp I checked with a multimeter, so knew that was good. Didn't check at the connector of the control unit but a scantool would have told me too. Then found out about that other evap temp sensor, so decided to disconnect that and have a listen. Quick and simple thing to do.

On manual? You try the control and check for movement. If no movement, check cable isn't broke or detached. If no movement, check flap/valve moves manually. If that all works, you check the matrix to see if it shuts off when the valve is off. Or check that the flap seals properly. Sounds less things to do, but in reality it's about the same amount of work. Just less electrical tools needed. Unfortunately I couldn't find my proper scantool in the mess I've got in my garage at the moment, so I had to do it more manually.

Both cases involve finding where in the chain of things the fault lies. Then dividing down and eliminating until the root cause is found.

Even engine ECUs of this era are pretty simple. Basically a bunch of inputs come in (rpm, engine rotation position, lambda, knock, manifold pressure, temperature, etc) that are put into a big table (engine maps) then used to determine how the outputs are driven (injectors, coils, valves, etc). Some sensors directly used for the maps (rpm, temp, manifold pressure) and others are used to tweak those maps (lambda, knock).

Brand new modern cars are however much more complex. For example, on climate many now take temperature readings from several points - including an IR camera type that measures the occupants head temperature. Still a process of elimination, but you need to use the scan tool even more instead of being able to use a multimeter or oscilloscope to find what isn't behaving correctly. Engine ECUs are a lot more smart too. With direct injection they need to exactly squirt at the right time while watching the result closely. They forward predict what the engine is likely to do based on how it's ran previously and try to adapt to suit. This can be done now as compute power has significantly increased.

As you've probably guessed from all my posts over the years, this sort of fault finding is what I enjoy most. Understanding and diagnosing complex systems is my day job and it's why I (mostly) enjoy doing the type of job I do.
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