My turn for the Check EV message

[xyzzy]

Our 2014 model has decided it does not want to behave as it should. The history:

A few months ago I drove the car normally to a park, stayed there for a few hours, then started home. A couple of miles from the park I was stopping at a red light when at the very last stage of stopping (car barely moving) there was a small jerk. The Check EV message came up and the aircon fan went onto maximum. No controls were responding, I could not put the car in park or neutral (it was stuck in drive), I could not turn the aircon fan off, I could not put the hazard flashers on and I could not even turn off the car. After some 30-40 seconds the car started to respond. I turned power off. waited some 10-15 seconds power on again and all was good (no Check EV message). We drove a short distance to the next red light where a similar jerk on stopping happened but no aircon fan and this time the car responded after maybe 7-10 seconds, again cycled power with 10-15 second wait and all was good. As it seemed to happen on stopping I made the call to jump onto the freeway and get home (or as close as I could). So onto the freeway keeping to the right lane and about a mile down the freeway I lose drive power, this time I get a power steering warning, then Check EV, then brake system failure warning, then back to Check EV. Murhpy's law applying, this happened just as I was near a busy on ramp. Managed to get to the emergency lane without drive, but steering and brakes working normally or close to normally. Also the seat warmers went into hyper drive, to the point I was worried the seat will melt and I was doing a bridge position to keep away from the seat. Car stuck in drive. After 10 seconds or so I was able to turn the car off. Again I waited some 10-15 seconds the car powered on with no errors and we drove some 8 miles down the freeway without any issues. At the exit ramp when I stopped at the red light, the now familiar small jerk and up comes the Check EV light. Again after 10-15 seconds the car starts responding (I was trying to put it into neutral to check for response), cycle the power and we drove home without any more issues including stopping at 2 red lights.

We have another car so my wife (who normally drives the EV) was instructed to use that one. Then life got in the way and now finally I have a chance to work on it.

Looking for patterns I found:

• When the Check EV fault comes up, if I remove my foot from the brake pedal the car will start to respond (so I can turn it off straight away)
• The fault is most easily replicated after the car has sat for a while
• When the Check EV come up, if I try to turn in on shortly after turning it off it will bring up the check EV warning immediately after the self check completes and force the car into neutral
• It needs to sit for longer than the previous 10-15 seconds, but if I let it sit turned off for a short while it will return to normal operation (no warnings)
• I have now had it lose power 3 times while in motion driving gently around my block, in all these cases it will give some jerks then run for a few car lengths then some more jerks and loss of drive.
• Now it generally gives a power steering warning before the Check EV warning

I replaced the 12V battery as an "in case" as the old battery was about 4 1/2 years old
Just under 1 year ago the engine seals were done by QC charge. Checking the speed sensor is dry.
We have owned this car from new and until a few years ago it was serviced by Toyota Carlsbad as specified in the manual.

It would be nice to get this car going again, but I don't want to sink too much money into trying.

 

[davewill]

If there was ever a time to plug into the car to retrieve diagnostic codes, this is it. Should be well worth having @aiflash or QC Charge do that for you.

 

[hokiematt]

The item that caught my attention was stating that the hazard lights wouldn't work; this particular circuit involves no computers, just a common flasher module. This makes me think you have a low voltage power problem, either something intermittent with the 12V feed or with a ground.

With the car in READY mode but still in park, I would poke around and wiggle/pull all of the wiring harnesses in the engine bay. Also look for any signs of damage: rodents have been know to eat the insulation on some wires that could now be exposed and intermittently shorting out. Look for corrosion/rust on the chassis where grounds are attached (typically a few medium size wires, often white with a black strip, crimped to a single ring terminal).

Has the vehicle ever been exposed to deep standing water?

 

[asavage]

Yeah, I got to ". . . and the aircon fan went onto maximum . . . " and thought "rats ate a wire". That's not a Tesla system, so this is going to be on the Toyota side.

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I used to get an Avalon (or Solara?) in the shop all the time with rat damage; mostly, they'd crawl in the intake up to the air filter and shred the nice, fluffy OEM air filter. I eventually fashioned a hardware cloth (wire mesh screen) baffle that stopped that one, and told the owner to acquire two cats

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For a couple of years, we were getting 80s/90s Fords in the shop with fuel injector wires eaten. I distinctly recall an E150 and a Thunderbird, both with a dead cylinder, caused by an injector wire chewed through.

 

[xyzzy]

Thank you for the replies so far. I too was thinking that the Check EV should not cause the other controls to misbehave. I had not thought of animals chewing wires. This car usually lives in a garage which has no signs of rodents, but it may be a case of a wire insulation has failed in some way.

I am wondering if there is a way for the Toyota side to cause the Check EV / no drive issue or if the Check EV shows there is a common path which is affecting both Toyota and Tesla sides?

 

[xyzzy]

Hmm so when I posted the original description of the issue, I also ordered the parts to get TPD going. I just got TPD connected and downloaded the logs from before the time of the original failure until now.

The first thing that happened is DI_f020 speed sensor problem detected, followed 7 seconds later by DI_w020 Speed sensor problem detected, then a minute and a half later by DI_f108 Drive not possible because of other system problem. Then a few days later with the car sitting in the garage, there are 12V battery related messages (CHG_f022, CHG_f039, BMS_f061)

While I was sitting in the car, with the car powered on downloading the logs DI_w020 popped up again (with no Check EV warning displayed).

So it looks like the speed sensor misbehaved. As I understand it, this would drop out the contactor, and with a weak battery and with no charging and headlights on the voltage probably dropped causing the Toyota systems to misbehave.

Need to research these error codes to better understand what they mean.

 

[hokiematt]

The 'Check EV' warning in the instrument cluster is based on a message sent from the Tesla gateway in the cargo area (inside left rear access panel) to the Toyota side of things. There is nothing on the Toyota side that would cause that message, and reading fault codes through the OBDII port under the dash will simply result in "P312F: propulsion control module requested malfunction indicator lamp (MIL)"

A bad speed sensor can cause the DI_w020/f020 error. Coolant in the inverter can also cause this error, and seems to be a more frequent issue with the coolant seal going bad in these aging drive units. It's definitely worth spending a few minutes to remove and inspect your speed sensor (accessible at the passenger end of the motor; see various threads here if needed) and see if there are traces of blue coolant on it.

The DI errors should not cause the contactors to drop out. You may have more than one problem if they are. A bad 12V battery will cause a host of odd issues; if your battery is more than a few years old, consider having it tested and perhaps replaced.

 

[xyzzy]

Thanks Hokiematt, I have recently checked the sensor and it was dry, as I expected as QC Charge replaced the seals just a year ago. As I recall when they worked on the car they had stated there was no fluid in the inverter. So unlikely to be that. I am hoping to check the sensor cables are intact, no shorts and connectors good later today or on the weekend.

12V battery was replaced last weekend as it was on the older side and while I was keeping the battery charged while the car sat in the garage, I felt it was an easy risk to address.

I don't know if the contactor was dropping out when this issue happened, I had read somewhere that it does if the speed sensor faults, but that was on the internet.

 

[asavage]

At least one person (@DougL) with those codes has recently reported that replacing the speed sensor fixed his.

 

[xyzzy]

Thanks Al,
I did come across that thread. The evidence is pointing to the sensor. Just need to check the wires / connectors to eliminate the easier options. I sure wish there was some way to test the sensor so I could be sure before spending $300 on a new one.

 

[asavage]

Nobody has posted an o'scope waveform of "good" and "bad" speed sensor signals, so there's no performance check to be done, AFAIK. Even then, most people don't own a 'scope, so if the good/bad waveforms were publicly available, few DIYers would be able to use that info. I mean, can you backprobe an automotive connector without compromising the weathertightness? It's a skill that you don't just have. And while you can use a piercing tool to tap that connector's leads, you have to re-seal it or the harness can become compromised. All this is not stuff that most DIYers know; they think they can just somehow use a DMM and it'll be able to give a GO/NOGO, but this speed sensor seems to fail in a different way that isn't amenable to DMM testing.

I often build a breakout harness to do this sort of thing, which is both expensive (in terms of time and assembly) and requires tools I've acquired that well exceed $300.

IOW, for most people, spending $300 as a gamble that may pay off or not, is still darned inexpensive compared to the alternatives. This is just modern living, I'm afraid.

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What I'd like to see is a "loaner" known-good speed sensor for this kind of situation. It's so easy to R&R that it's no hassle to swap it twice.

 

[alflash]

Note.
Tesla's opinion on this codes for RAV4EV
https://alflash.com.ua/2019/to_rav4ev/di_w008cause.png *)

IMHO.
If the vehicle is in IGN ON the failure is reported as a FAULT (for example: DI_f020). The vehicle opens contactors, or keeps them open.
If the vehicle is in Drive Mode, the failure is reported as a WARNING (for example: DI_w020), but does not open the contactors, to prevent loss of drive.

1/2 off-topic. I hope this can be useful for those who repair their cars themselves.
https://www.amazon.ca/dp/B0CTXGTVY2/
https://www.amazon.com/ZOTEK-Automotive-Oscilloscope-Multimeter-Tester、Voltage/dp/B0C3D1KVPB

*) HINT: These are undocumented codes which are not mentioned in the repair manual for this RAV4EV model.
Just like some others, for example, DI_w115

p.s. Topic about RAV4EV with DI_w020 and DI _f108
https://www.myrav4ev.com/threads/er...cement-and-problems-with-re-flash.2645/page-3