RAV4 XA50 PHEV/Prime or Suzuki Across HV Cable (CABLEGATE!) Corrosion Prevention Treatment

So there is a well documented issue with the Rav4 Hybrid whereby the high voltage cable that connects the battery to the rear motor corrodes to the point that it stops the hybrid system from working. In this instructable I've documented how I safely took the plug off, inspected it and treated it with some preventative maintenance.

My car isn't actually a Rav4 - it's a Suzuki Across. That's badge engineered Rav4, made by Toyota from Toyota parts in the Toyota factory, but with Suzuki badging applied. It's part of a deal between Suzuki and Toyota to share car platforms. It's pretty rare too - as of Dec 2022 there were only 360 in the UK. The headlights and grill are different (sourced, I believe, from the Toyota Wildlander model sold in China) but it's mechanically the same.

The car was 2 years and 4 months old, and has done 24,000 miles in the UK. We get some ice in the UK, and rare snow, so it's not been in a particularly harsh environment for its years, but corrosion was still visible on inspection.

But haven't you invalidated your warranty?

Maybe on that component, but Suzuki's don't have the 10 year warranty promised by Toyota - only 3 years, so the warranty expires in 8 months time. While there has been an extension to the Toyota warranty for this part in the US (and maybe Canada?), I believe it's only applicable to the Hybrid, not the PHEV/Prime, and not elsewhere, and not to Suzuki. So rather than wait and see if the dealer will do me right (which is unlikely) should it fail (which is possible), I thought I'd do some preventative maintenance and try and get over a decade out of this part before it needs replacing.

Is your car affected by the cablegate issue?

Officially no, because it's a PHEV/Prime, and its a Suzuki not a Toyota, but having taken it apart, I reckon it is affected, and that the corrosion would have become an issue in years to come, but hopefully my treatment will keep it going.

Isn't the HV system dangerous?

Oh yes, deadly. I'm not recommending anyone does this, just sharing my own experience. I made an informed risk/reward calculation and went and did this. Your risk appetite may be different from mine.

I've uploaded a PDF from Toyota EU that sets out the steps for making the hybrid system safe (p16 onwards). At the time of writing, the original is also sourced here.

• 10 mm socket (or 393.7 thousands of an inch as I believe they are called in the US)
• 12 mm socket (236.2 thou)
• Socket wrench
• Socket extension
• Small flathead screwdriver to pop out the plastic rivets
• Dielectric Grease (I did some reading on the difference between dielectric grease and silicone grease, and believe what i purchased and pictured is genuine dielectric grease with a proper, published data sheet)

SEE OFFICIAL TOYOTA INSTRUCTIONS

The High Voltage battery is protected by relay switches which are only closed whene there is some power coming form the 12V battery. So disconnecting the 12v battery negative terminal with a 10mm socket, and tuck the lead/connector out the way so that it can't accidentally come back in to contact with the battery terminal.

SEE OFFICIAL TOYOTA INSTRUCTIONS

Next there are three covers covering the service socket that isolates the High Voltage battery that need to be removed.

In the PHEV/Prime (as pictured) the connector is under the plastic cover between the rear passenger footwells.

In the Hybrid, the connector is behind the air intake-panel on the base of the rear bench seat on the driver's-side (UK & RoI) or passenger-side (elsewhere). I don't have photos of that, but found someone's Youtube video which shows it.

1 - The plastic panel has 4 concealed clips holding it on. Just lever it up with your fingers and the 4 clips will come undone.

2 - The next panel is secured with 3 12mm bolts. Take these bolts out then the panel comes off (the sealing foam was slightly adhesive so it did need a bit of force to overcome the adhesion).

3 - The lowest panel is secured with 4 10mm bolts. Take these bolts off and the panel lifts off.

With the covers removed you can now see the Service plug. View the animated GIF above to see how to remove it, by clicking the handle towards the front of the car, then rotating it up 90 degress. This rotations lifts the connector out of it's holder, and it is then free to just pick up out the whole.

A KTBD cycle is a standard unit of time used in Britain. It stands for Kettle/Tea/Brew/Drink cycle, and is equivalent to 11 minutes in the rest of the world (except in the US, where I believe it is the equivalent of "11.002 min US" or "11.002 freedom minutes").

This time period allows any capacitors that may have held a charge from the HV battery to calm down a bit.

Now, underneath the car. I had car ramps, which made it easier to photograph, but I believe there is enough space under the Rav4 to do this without raising it

There are 3x 10mm bolts holding the cover in place, in a row at the back (see photo with green arrows). Take them out and keep them safe.

Then there are 3 plastic clips: 2 at the rear of the car and one at the front (see photo with red arrows). These are a bit fiddly. They come in two parts: a peg and a sleeve. You need to lever out the peg only with a small flathead screwdriver, then once the peg is out, the sleeve is loosened and will also come out. Keep these safe also.

Once the panel is out, take some time (potentially another full KTBD cycle) to marvel at the amount of crud that has accumulated on the top of the panel.

Here is the fabled orange connector! It's a 2020 car, so it's the original fully enclosed one, not the new cutaway one, although whether that new design will be successful in remedying the problem remains to be seen!

The connector is attached with 2 x 10mm bolts - they're quite long, keep turning!

Once they are out, the plug pulls right out.

I had a bit of trouble getting the casing apart apart, managed to break a couple of the plastic clips. Couldn't find an elegant way of getting them undone, but they went back together securely. There was a surprising amount of crud inside the connector.

There is definite corrosion on the crimped colar for the exposed wire - I think it's electronic shielding wire (or maybe mechanical support?). The electrical contacts themselves looked OK - bright copper, they're just visible on the first photo.

To my amateur eye, it looks like the source of the problem is the crimp ring for the shielding, which judging by the brown rust is a ferrous metal. It's attached to aluminium casing, and they're reacting together. Iron oxide and aluminium are pretty reactive (thermite!), so once it starts to go it will accelerate.

I applied dielectric grease around the seal between the two components (i.e. on the aluminium casing and the rubber seal), and gave the exposed shielding wire a liberal coat too. I could have put it on the copper contacts itself but didn't.

I could have also cut the hole in the casing to make it the same as the new Toyota part, but I will wait until the warranty period is expired before I do that, because I'm not sure what the Suzuki dealer would make of that rather visible hack.

The Youtuber I referenced earlier has done a follow-up video where he does a more measured application of similar grease, but in all honesty I was a bit slap dash, which may be an ethnic thing, and why we don't have any large scale British-owned car brands these days!

Reassembly is just a reverse of the steps above.