Geralt

This URL didn't quite work for me. But this did: https://www.toyota.co.jp/recall-search/dc/en/search Nice to have an unequivocal result for the van....and a characteristically Japanese apology!

I think access to ABS is relatively easy so changing it might not be too tricky. Bleeding the system might be complicated but I think any garage could do that. But I think that is a bridge to be crossed if you come to it. It might be the instrument cluster. Yes definitely do that first. Problem might go away after re-seating the connectors.

Sorry to hear you're still having trouble but I think changing those sensors was never going to solve the issue. As previously mentioned, I'm fairly sure vehicle speed comes from ABS ECU via instrument cluster. If I were you I would be getting a basic oscilloscope and tapping the SI and SPS+ signals on the back of the instrument cluster to check that you have the 4 pulse signals while somebody else drives the van. If one of them is missing then that indicates the source of the issue.

You mean the transmission shaft speed sensors?

I tried Techstream v12 today using the Virtual Machine (Win XP) method but I get identical results. So I'm further convinced it's either the vehicle or the MVCI cable. Looks like I'll have to try debugging with the Arduino after all.

OK, I see, So do you have a 24V (or 2 x 12V) leisure battery then?

It's part of the conversion. Not original. Not as a far as I know. Could you let us know how you determined this please?

I'm amazed the volume change with temperature is noticeable. What is your transmission code? Mine starts with a U. Maybe Google that for maintenance info.

This means the CAN bus connection is interrupted. This is a pair of wires forming the serial communication medium. Check connectors for tightness and corrosion on the pins. I very much doubt this code would occur due to faulty battery cells.

Doesn't it have a dipstick to check the level?

An earlier version (v17) made no difference. I could be wrong but I think the diagnostic options are very limited on the 2003 - 2004 Alphards to those ECUs which can affect tailpipe emissions via K-Line i.e. Engine/Transmission and ABS and that's why you can't connect to other ECUs on your 2004. According to your profile you have a 2007 model (too) so how do you get on with that? If you can talk to loads more ECUs I think this probably proves my theory. I haven't solved my issue yet but I have a plan to use an Arduino to log the K-Line comms and see who's at fault. Techstream or Engine ECU. Whether it gets to the top of my To Do list we shall see.

I don't think it has tappets, rather it has overhead cams. I think that perhaps it's VVT noise as oil pressure is rising. Perhaps it's always been there and now you notice it because the background engine noise is reduced? Anyway, if you have plenty of oil and no check engine or oil pressure lamps illuminated then I wouldn't lose any sleep about it.

I think the first step is to get the OEM speaker part numbers then maybe a car audio specialist could advise suitable replacements. https://partsouq.com/en/catalog/genuine/locate?c=TOYOTA00 Put in your VIN then search for speaker then get the part number. Then on eBay you can find out which other models share the speaker which gives you more options. For example, my Gen 1 Alphie shares a front speaker with a Land Cruiser.

I assume that the air con guy confirmed by other means that there is pressure in the system and that is why he suspects the switch is faulty? Anyway, I did some digging in the wiring diagrams. Apparently this is a "triple pressure switch". As you can see it has two pairs of terminals with colours: Red-bLue / Light Green - Black Black-Orange / White-Black If I were you I would first check the A/C fuse is intact then diagnose the switch by shorting the R-L/LG-B together and shorting B-O/W-B together. If the A/C system then blows cold, air con guy is correct, it is the switch at fault. If not, then it is not the switch. If it is the switch then it looks like this one in Oz: https://www.dcpowersolutions.com.au/denso-air-conditioning-pressure-switch I looked on PartSouq but it is not identified as a separate part strangely but I guess you can worry about that when you've confirmed it is the switch.

Is it either of these coolboxes? : https://www.halfords.com/motoring/travel-accessories/coolboxes/halfords-24-litre-12v-electric-coolbox-748115.html https://www.halfords.com/motoring/travel-accessories/coolboxes/halfords-14-litre-12v-electric-coolbox-748107.html Both pages say 40W / (~3.5A @ 12V). So just 0.5mm² cable should be plenty. Maybe you misread 3.5A for 35A? I think it's always better to err on the side of caution and add a fuse for electrical safety and, if it blows, will be more readily accessible. Head over to 12V Planet for some good advisee: https://www.12voltplanet.co.uk/knowledge-centre.html

Possibly a parking sensor fault warning: https://www.cx3forums.co.uk/viewtopic.php?t=2356

Here's the fuse locations:

That's great so what is the code reader telling you about the cause of the engine light this time?

I did a bit more digging. Further to my previous post, I think this confirms the signal route for vehicle speed in the Alphard too: https://www.toyaris4.com/toyota_yaris_vehicle_speed_sensor_a_no_signal_p050031_-1132.html There are four pulses per rotation of a wheel on the SPS+ signal. The circuit detail broadly matches the Alphard Gen 1 wiring diagram too: The only contradictory evidence is the fact your odo keeps incrementing. I'm baffled as to how!

Safe trip. Yes we're pencilled in the for 2 but not committed yet.

If it drives OK I should think that you won't do any damage. BTW, is your vehicle 2002 or 2007? If the former then it's like mine. I can see in the wiring diagram that the ABS unit sends a speed signal (SI) to instrument pack. The instrument pack then processes and sends out a modified speed signal (SPS+) to other ECUs like Engine Management, Body Control, sat nav etc. It's the engine management ECU that's reporting P0500 probably hence the MIL on. I still don't think the issue is gearbox sensors. It's more likely that it's ABS but then I don't know why you're not seeing a brake fault light on the dash in that case.

In that case I doubt there is a problem with the incoming vehicle speed signal. Usually a single signal is used to update both speedo and odometer but I'm not certain of that so am prepared to be corrected. It could be that the instrument cluster speedo motor is broken. Also if it runs well and changes gear at the right times that too suggests the gearbox speed sensors are OK in my view. Has your OBD reader arrived?

Just for reference, the manual says the sonar system should start working under 50cm. At 25cm the lights and buzzer should be continuously on.

By odometer OK, you mean it still increments?

I think you posted an engine warning light problem thread before. The advice then was to buy an OBD reader. Did you get one in the end?