Hi All,

A couple of days ago I finally got a chance to go get my A/C regassed at my local Toyota/Lexus independent - just in time for the mini-heatwave we're having in the UK.

The system was pretty much empty (not a good sign), but even after a full recharge the compressor will not run. (Turning on the A/C does cause idle-up, however.)

Techstream showed no CAN bus comms w/A/C system (along with SRS, for some reason - even though the airbag light does not stay on after startup).

Now, given that I bought the car less than 3 months ago, this is subject to a warranty repair. (Not that it's a great warranty - they'll only pay up to £500 not including diagnostics and not including wiring looms. Whether I still have legal recourse against the dealer is a matter for debate!)

Anyhow, it's booked to go back in on July 4th, so between now and then I need to gather as much information as I can, so as to avoid unnecessary work in locating the problem.

On this basis, any pointers would be very much appreciated!

Thanks,

Rich

 

Forgot to mention that the dealer claimed that the previous owner had had the subwoofer reconditioned (even though I have no documentary evidence of this apart from the fact that it works just fine), and the rear air struts have been replaced (with KYB). Presumably, then, the rear seat would have had to be taken out for either (or both) of these jobs? (Maybe a connector wasn't put back WRT the rear A/C controls or the cooler behind the armrest?) And incidentally, there's a bit of PVC tape round one of the wires in the fusebox in the trunk - no idea what, I'll take a picture of it when I can.
Also, the car has had three column telescoping motors; again I'm wondering if something was disturbed WRT the SRS - even though everything looks correct.

 

Sorry for your trouble. It sounds like a bus signal line problem to me. The possibility of a failed bus transmitter/receiver is rather low in my past experience. Most of the problems were pinched bus signal cables or open cables. In case of a bus signal line's problem, I'd use a TDR for a quick troubleshooting. It's a very convenient equipment to find out the exact failing point of the bus signal line but dealer's usually don't have it.

 

Thank you Yamae,

Yes, it's unlikely that my local independent would have a TDR for CAN Bus.

One of my concerns, over and above that of the non-working A/C, is that the SRS might now be at risk of accidental deployment (e.g. by electrostatic build-up if that section is unterminated, or during investigation). The side curtain airbags (with their proximity to the ear) trouble me greatly!

I do now have the set of workshop manuals (Bishko reprints) but have not yet had a chance to wade into them!

Best,

Richard

 

As an update, the rear A/C fuse (3) has clearly been replaced. (Rear A/C controls, in the armrest, also give the correct indications.)
Any clue as to what the taped wire is for?
Planning to dive into it tomorrow.

 

It gets better. Lifting the fusebox lid reveals yet another taped wire - having been cut and spliced - appallingly. Now to get lost in the Bishko books - but not having the electrical system supplement I'm not sure how easily I'll find out what these wires are for.

 

Forget cut and spliced. They've been stripped and soldered-to. Horifically.
Blue spacer there only to make it clearer to see.
Put it this way: I'd like to meet the person that did this...

Incidentally, I also found a black, braided co-ax cable, roughly 3.5mm diameter, just cut and hanging there. Radio or car-phone? Not sure. (The radio works OK-ish...)

 

Hi friend,

Red & Black wire is ok, it looks like a stranded copper core wire from best I can see and can be taped no problem, tape well.

For the white wire, can't really see what's going on but I'd re-splice it and clean it up.
If it is a shielded wire with foil or metal braid surrounding a copper core this needs to be done more carefully to keep shield intact and separate from copper wire core(if it's shielded) but can't see.

 

Thanks Margate,

Yes, I can repair the damage (however I wish I had a pin extractor, then I could remove the excess solder and apply heatshrink to the affected areas).

I was more interested to know exactly what these wires are for, and whether they're related to the non-working A/C - possibly the rear system causing it.

Best,

R

 

My apologies, I wish I can be more help.

When I was considering buying one of this model for my elderly father to cruise around in, I downloaded the entire TIS electrical wiring for this car.
It's on a USB somewhere and haven't been able to find it and I've looked everywhere.

The "overall" wiring diagrams will be hard to diagnose this IMO but the TIS Electrical wiring schemtics is where I would go and is much better and detailed and organized with connector & plug info.
A 2 day membership and download ALL electrical from Toyota/TIS I can with connectors, harness junction drawings, ground point drawings, electrical component locations, everything!

With that it will be easier to find a point of attack for diagnosis(with max precision) and even someone like myself who does diagnostics for my job it will still take an hour or two to completely understand the path and flow and determine best way to start.

In general the rule is physical inspection first when possible and then note any components not working properly as clues where to begin.
A bad ECU can shut down a data bus with unpredictable symptoms- so can a noisy data bus.

 

Go to this site and you will find all the repair manual and electrical diagrams online, Has come in handy for me dozens of times> https://www.lexusy.pl/LS430/contents/index3.html

 

Many thanks, I'll have a look!

 

Managed to tidy these up somewhat. Fortunately the add-on wires were simply wrapped round (largely dry-jointed I might add!) and no strands were broken. I was able to pare back the insulation so as to make nice clean edges and I've temporarily bound them with self-amalgamating tape that does not leave a sticky residue.

However, I really want to remove the pins so as to put heat-shrink sleeving over the wires. (I've tried using jeweller's screwdrivers, but cannot displace the spring clip on the pin.) Please can somebody advise me as to specifically what type of pin extractor tool I need for this connector - there being many types available?

I never intended to steer this thread off-topic - sorry!

Thanks again,

R

 

Might be getting somewhere at last.

Evidently the compressor is not generating a tacho signal, probably due to something having sheared inside. (Because of lack of oil, maybe?) Therefore computer says no and won't even try to engage. This could explain why I was seeing nothing at the clutch connector (i.e. using a 5W test lamp) with the A/C on.

Plus, theres a huge leak somewhere and all my gas is gone - even before taking the compressor out! (£60 into thin air - literally!)

Should have guessed that if the dealer could have fixed it easily, he would have.

All the CAN bus stuff could have been a red herring!

R

 

My 2006 LS had a leak small and would lose fluid over a season. refilled for a couple of years.
Finally took it to a repair shop not Lexus who did a drain and vacuum. Said I have a small leak somewhere.
After refill next day totally empty. Did a refill on my own with gauges and pressure would not come up.
Found the major leak in the black rubber low pressure side (fill valve).
This hose had de-laminated and the running a vacuum finished it off.
Used one $35 e-bay and one year later cool and all is well checked pressure with gauge. ok
Compressor protects itself is no fluid.