Help with Insulation Test and DTC Codes

I am using a chinese megger VICI VC60B+. as per the instruction on the repair manual, one lead to the frame wire and the other to the body ground. also notice that the wire is not connected to the other end either (the hybrid battery) from the previous step.
My results with the megger don't give me any readings or resistance when it should be 10 M ohms. the ones I tested at the junk yard had the same readings as mine. any thoughts? is there another way to test the frame wire?

 

Well, note that the manual says "Standard resistance: 10 MΩ or higher."

If your meter is giving you an offscale-high "no reading", that falls under "or higher."

Are you not sure that's what's happening? Do you have a photo of the "no reading" reading?

 

but right before that it says "using a Megohmmeter". that seems very confusing.

I think you are right "no reading", that falls under "or higher." the reading basically doesn't change at all when testing, so it is zero. I can take a picture

 

I also ran into the same issue, thought my cable was bad, was using the VICI VC60B+. If I recall correctly I ended up disconnecting all cables and testing each line individually. It turned out I just needed more practice using the meter and understanding the reaction time and what your actual testing. One part of the issue I found is I thought I had a shielding issue, turned out I had contaminated the end of the cable with a semiconductive fluid (electrolyte from a lead-acid battery). After cleaning the cable the short disappeared.

 

Yes, do take a picture; "it is zero" is pretty much the absolute complete opposite of what I think you're seeing.

They say "using a megohmmeter" to make sure that you're using an instrument that produces a high enough voltage to catch insulation flaws that an ordinary multimeter might miss. Still, if the resistance reads off the scale of your megohmmeter, it is certainly "10 MΩ or higher."

 

wardtp. I just did a bunch of testing:

Standard resistance testing:
1. I decided to extend the cables of my meter to measure the resistance of each end of the long cable from one end to to the other end. the results were good, there was conductivity with no loss on each cable.
2. I tested for conductivity again from one end to the other end but this time I connected the cable to the metal jacket/sleeve at the invertor connector and this time I got about 2.5 Mega ohms of standard resistance on the upper cable and infinite resistance on the lower cable.

Megometer resistance testing:
1. I measured each cable from the invertor side to the closest body ground on the front of the engine and I got infinite resistance for both.
2. I then measured the upper invertor connector at the metal jacket inside the conductor as you described and I do get conductivity but only when I use the Megometter. when I use standard resistance it doesn't detect any resistance and it goes to infinitive.

I think this means that the upper cable is slightly faulty. I am planning to compare it again with the ones at the junkyard to test the resistance of the metal sleeve jacket. I only tested them to the center conector for the cables and they all had infinitive resistance like mine when using the megameter.

Then I got underneath the car to inspect the cable run that is embeded in a hard plastic outer shell. I did find an area that was a bit rough where it could have possibly rubbed against or be hit by a road hazard. I think this could be a possible source of the faulty cable as I don't see any water intrusion or corrosion at any of the ends.

lunacy, no electrolites issues here. like Wardtp said, this is unlikely in this area.

 

This is the frame wire connector showing the center conector and the outer metal sleeve/jacket that Wardtp and I are referring to. this is using an extension cable so I can reach from the front of the car to the back of the car with my multimeter.

Posted via the PriusChat mobile app.

 

This is the default screen when you don't get any readings or sounds from the mega meter, which I think it means there is not conductivity at all. Chapman, I am not sure what you mean with it might "be the absolute complete opposite of what I think I am seeing". please explain. thank you.

Posted via the PriusChat mobile app.

 

unfortunately I also have to replace the inverter besides the frame wire cable. but I am hoping that would fix this error code.

 

It's not super-easy to find the manual for your megger online (the thing is, there seem to be at least two different variants floating around with the model name "VC60B+", under a bunch of different manufacturer names, where one variant has a selector knob like yours, and another variant has buttons).

I think this might be from the right one:



So, per item 2, the indication for "over range" is where only the most significant digit (MSD) "1" shows, as in your photo. You have a "200 MΩ" scale selected, so "over range" means the resistance you are measuring is higher than 200 MΩ. And higher than 200 MΩ is definitely "10 MΩ or higher", so the meter is telling you that the cable you are measuring is just fine.

 

I just went and checked my Vici VC60+, that I bought in September 2018. The photo you posted is the screen you get when it's in megger mode, but not measuring anything. In megger mode, you also have to push that round orange button labeled "push to test" to get the meter to actually make a measurement. You can either push the round button, take a reading, and let go, or push and turn the round button to lock it on to take readings continuously. While it's measuring, you will get an intermittent series of beeps from a beeper inside the meter.

If it's in megger mode, and measuring (the orange button is pushed down), there is a "lightning bolt inside a triangle" high-voltage indicator on the LCD, just to the left of the "1" digit in your photo. If the orange button is pushed down, the high-voltage indicator is on, and the thing the meter is connected to has higher resistance than the meter can currently test, you get the "1." indication, which means "over range on the high side".

If you put the meter in megger mode, hooked the leads to something on your car, pushed the orange button, the meter started beeping, and the display just says "1." like that - it means that the thing you're connected to has higher resistance than the limit of the meter in that range - 200 megohms, in that photo. Usually that's what you want.

It's also possible that when you make a test, the meter will flash a reading other than "1." for a second, and then change to "1.". From what I understand, that is OK. Most megger instructions I have read tell you to take readings for several seconds (at least 5 to 10) before accepting the "final" reading. There may be a small bit of capacitance in the thing you're measuring, and it has to "charge up" with the applied voltage, before you can see if there's also a low enough resistance to worry about.

The other indication you can get, while the orange button is pushed down, is that the beeper will start beeping continuously. When that happens, that means the resistance of the thing you're measuring is so low that the meter isn't able to develop the full high voltage (either 1000 V, 500 V, or 250 V for this meter). If that happens, you can try switching to a lower voltage range and testing again.

This post Chasing info code 123 *without* P3000? Or do I need a better scan tool? | PriusChat is the first one where I posted results from meggering my Gen1 last year. The quick version of those results follows. All the service manual figures are for a Gen1, so you should use the ones for your Gen2 instead:

---
At 500 volts on the meter, the two DC cables from the traction battery to the inverter, the megger always showed over-range - more than 200 megohms. The spec is 10 megohms, so that test passed.

When meggering between each pin in the MG1 and MG2 connectors (the motor side of the connector) and body ground , the megger started at a lower reading (around 20 megohms), and then rose over the course of a few seconds to over-range. Again, the spec is 10 megohms, so I believe those passed.

Finally, I meggered between all eight of the MG1, MG2, and battery terminals at the inverter, and body ground. All eight read 1.1 megohms on my meter. Spec for this is 0.9 megohms, so that passed.
---

In my case, I ended up opening up the traction battery pack, taking off all of the bus bars, cleaning the module ends, cleaning the ring terminals on the main + and - wires and on the service plug wires, applying a wire brush and vinegar to the bus bars, drying everything out, and reinstalling, and the "leak" code hasn't been back for about 15 months and 5,000+ miles.

When I was shopping for mine, I saw Vici, Victor, Samyo, and Kiamitor. Mine is a "VC60B+"; I think I also saw just "VC60B" and "VC60". I also saw the same variation of some having a rotary knob and others having buttons. At the time, they all started at about US$40 and went up from there.

 

duplicate - deleted

 

yes the picture above I attached was just a sample of the value without pressing the orange button which remain at "1" prior to testing and/or "above range" during insulation testing. thanks for the clarification. I just think the manufacture should have come with a different signal for both settings.

The whole insulation testing appears to be inversely proportional to resistance testing and that is why I was a bit confuse.

In my case I did all that and I have moved to further testing since the batt is good. I determined I have a bad inverter and possibly a bad frame wire. Thanks to the final code on techstream, this diagnostic is now confirmed.

 

1. are there any wizard electronic gurus out there that can comment on this problem with the internal metal sleeve/jacket that it is in the conector of the frame wire (shown below, see picture) that plugs into the inverter?

2. what is the function of this metal sleeve, additional insulation or protection? is it inside the cable or just the conector? is it just floating on the outer shell of the main wire?

 

The high-voltage cables are shielded. The outer shield is continuous from end to end and through the connectors. All of the high voltage parts of the circuit are floating with respect to body ground, but the shields are grounded to the body.

That has a couple of effects. 1) any shielded cable will tend to reduce the emission of radio interference if there are rapid changes of the current flowing within. I don't know if this is an important reason for Toyota shielding the wires in this case, but it's one popular reason to shield cables. 2) the end-to-end grounded shield means that any damage to a high-voltage cable anywhere along its length can be immediately detected by the car's ground-fault detector.

 

SOLVED. here is the UPDATE.

Short version: yesterday I found a good working framewire at the junkyard. this morning I hooked it up and I didn't get any error codes after running the car for 15 minutes and changing gears! Big thanks to Wardtp who previously had this same problem. I do want to add to future readers that Wardtp and I found this voltage fault at the frame wire by experimentation, because if you follow the repair manual procedure for diagnostics you will think the wire is good. so read the previous post carefully and look at the pictures previously I posted to check where you need to test.

Long version: yesterday I went again on a expedition through the biggest junkyard jungle in town with my machete (the megger) looking for a prius that had a decent frame wire. most outlets were still very wet from the recent rain so I had to shake them up and dry them prior to megger testing, this is what the pacific northwest has to offer for 9 months, I tested a total of 3 prius and the third one was the charm. the first one was sitting there for awhile and perhaps water got inside the wire and had similar readings as mine, the second one was slightly better, the third one was great and also very easy to take out since most of the parts of the front of the car was removed. overall it took me about 15 min max to uninstall something that will take like couple of hours on a prius with complete engine. This morning I got up at 4:30am very excited to try the wire out, I didn't even want to waste time removing my old frame wire which it will take some time. I instead ran the frame wire from outside of the car just for testing purposes. as soon as it was hooked, I set up my scanner and started the troubleshooting, I turn ignition on and I was not expecting any error codes as I have not gotten any codes on this code previously (if you were to get the error code at this phase, this would point out to a voltage leak in the battery area). so I proceeded to get the car into "ready" and shift to neutral right away, I waited several minutes and I was so happy at this point as that is when I the error code always would pop up and this time was clear. then I shifted into gear and move the car for several minutes and the code never came back.

I will report back after a few weeks of driving and also what I find out about the bad frame wire. I am planning to dissecting the wire to look for shorts or see if the connector is at fault. but for now I have to catch up with family, kids and my biking buddies. merry christmas and happy holidays to everyone and thanks to everyone who have helped me and others on the chat.

 

@Wardtp,

it's been suggested on another thread that I'm not following what you have found in this thread.

It's possible. One place where some more information could make your findings clearer would be in your post #8:

If you still remember, could you specify here exactly where the test probes of your megger were placed for these tests?

The last sentence quoted above says "to the frame of the car". Does that mean that one of your test probes was on the frame of the car for that test?

Hmm, wait, I think you did specify later, in post #24:

Ok, that gives a clear picture. There is a fault in the frame wire, manifesting as leakage between the wire's center conductor and its shield. (That's exactly why the HV wires are shielded—to be sure of detecting such leakage.)

In your test (1), the forward end of the frame wire is still attached to the inverter, so the wire's shield is in contact with the inverter which is bolted to the frame of the car, so your megger test between the center conductor and the frame of the car has a leakage path to detect.

In your test (2), you've unplugged the frame wire from the inverter, breaking the continuity from that end of the shield to the car frame. If you're testing from the aft end of the frame wire, maybe you have that end already disconnected, so that end's shield connections weren't in contact with the car body either?

(detail of image from here)

Your frame wire still has a fault somewhere, detectable between the center conductor and shield, but you don't detect it if the frame wire is unhooked at both ends and the shields aren't in contact with the car frame anywhere. You're just not really testing it in that case.

In your test (3), using the megger probes directly between the center conductor and shield, you are back to testing the same path as in (1), only even more directly, so naturally you see the fault again.

In the old 2006 manual version that kicks around the web, I can see there's a frame wire test in step 16, where the previous step (15) could only be reached by an NG result in step 4, and 15 has you disconnect all the HV terminals of the system main relays. If someone were to do that by also undoing the shield connections back there, then that would explain step 16 giving a false pass result.

One other thing I wondered about in post #8 was:

That is what I would expect, but can you give details of the megger reading that showed you the fault?

I am curious, because tri4all described obtaining a VC60B+ "overrange" reading in some tests, which would constitute a passing test, not a failing one. However, you did say in post #31 (after a photo of the overrange display):

I am assuming what you meant is you saw overrange in your test under conditions (2), but that you saw readings below the published standard under conditions (1) and (3). Is that close?