DASH Error Lights Exclamation w/Triangle, VSC, and small Exclamation - Car runs great?

P0A80 points to a bad traction battery while P0A84 points to a problem with the traction battery ventilation system. Since you replaced all of the components and the car is still logging P0A84, I believe that you need to carefully inspect the wiring harness between the traction battery ECU (which is the one that logs the DTC) and the components: battery blower motor controller, blower motor, and the battery blower relay.

Download electrical wiring diagram and repair manual info at techinfo.toyota.com to help you understand the wiring of this circuit.

Can this particular wiring harness be easily swapped between cars? If not, then use the repair manual's troubleshooting info on DTC P0A84 to help you check the wiring harness with a digital multimeter.

 

Yes probably the HV fan is not operational and overheating the batteries but not sure why the HV batteries are getting hot to begin with. Or you have the fan duct work all messed up and have a vent blockage to outside.

You never posted where you live so not sure of your climate and topography if you have alot of hill's in your commute. Hill's are hard on hard on the Hybrid Battery.

Not sure what your reading the codes with but if its a Techstream or a Scan Scan gauge you can use those devices to turn the HV fan at various speeds for a test.

 

Reviving an old thread here because Ema threw the 2 codes listed here on my way home from the mountains of North Carolina. She is giving both the P3000 and POA84. Of the two I believe the POA84 is the potential root cause. My cooling fan almost never runs and it came on a couple of times while we were hiking over the weekend, maybe more. Lots of long downhills on twisty roads at lower speeds so the battery gets charged and could be getting hot to have the fan come on? Then on a big downhill coming out of Asheville I got the red triangle, yellow exclamation point, VSC and "Problem" "!" point on the MFD. At the bottom of the hill I pulled over and turned her off. The cooling fan was running when I turned her off.

I checked everything I could but didn't have my mini vci so couldn't pull codes. Powering back up, the yellow exclamation point and VSC light were out. I drove her home, probably 100 miles monitoring temps and stuff on my ScanGauge. My mini vci cable was busted and my new one arrived on Tuesday that I had ordered so I pulled the codes then. The POA84 had me looking at the cooling fan. Everything appeared good, no blockages or dirt. I did find about 2" of water in my aux battery compartment, grrrr. So maybe the motor is going bad for the cooling fan?

You can test the cooling fan with the Techstream software so I did but don't have any point of reference or prints to use as a guide so was hoping someone here could help? The fan has 7 settings (0-6) with 0 being off and 6 being "full speed". I believe the parameter labeled "VMF Fan Motor" is for the cooling fan. Again hoping someone here can help. The readings are as follows:
0 = 0.0 V
1 = 9.8 V
2 = 9.4 V
3 = 8.8 V
4 = 7.4 V
5 = 5.2 V
6 = 3.2 V

Those appear to be VDC but what strikes me as odd is why does the voltage decrease as the fan speed increases. I would think that the voltage would be maximum at the maximum speed? Again, I don't have any prints so am hoping someone here can lend a hand. To me it appears the motor is bad even though it runs?

Also the vent ducting wasn't connected as tight as I would like in the motor area going to the battery so I duct taped that together a little better to ensure proper airflow to the battery but suspect a bad fan could be causing the P3000 hybrid ECU issue?

FYI, all the HV battery blocks are within .1 V of each other and all have identical internal resistance of 0.019. So I think the HV battery is just fine itself. I didn't see any wide swings from full green to purple or ANY unusual battery activity at all since the codes were thrown.

Any help, thoughts or ideas would be greatly appreciated. Thanks in advance!!!!

Chris

 

how many miles on the old girl?

 

399,714 ... and counting

 

wow.

 

Hi Chris,

The potential failed items include:

Wire harness or connector
BATT FAN fuse
Battery blower relay No. 1
Battery blower assembly
Quarter vent duct (battery blower motor controller)
Battery ECU

Since you found water nearby, I would suspect a bad connection in the associated wiring harness or the battery blower motor controller.

The Toyota repair manual goes into considerable detail regarding how to verify the wire harness. The battery blower motor controller adjusts the voltage applied to the blower motor, based upon a pulse modulated signal from the battery ECU.

The battery ECU is responsible for monitoring temperature of the battery modules and deciding the appropriate voltage to apply to the blower motor via the blower motor controller. It sends the pulse modulated signal to the blower motor controller to adjust the blower motor voltage.

The battery ECU then measures the actual voltage applied to the battery blower motor and logs the fault code when the voltage measured is less than expected. It is possible that ECU has failed, although all of the other possible items should first be tested and found good before replacing the ECU.

The voltage measurements reported via Mini VCI are very interesting. I suggest putting a voltmeter across the fan terminals to see what the actual readings should be. Clearly as the voltage applied to the fan motor increases, the fan speed will increase.

Suppose the ground connection for the blower motor controller is bad. An additional resistance introduced between the motor control circuitry and ground would result in a unintended voltage drop. As the current drawn by the blower motor increases, the voltage drop across that resistance would also increase.

It doesn't take much additional resistance to cause a problem. Suppose you have 1 ohm of extra resistance, and the blower motor wants to draw 5A current. The voltage drop across that extra resistance would be 5V based upon Ohm's Law.

That might screw up the voltage measurements at the fan motor. So the wiring harness checks will probably turn out to be an important step. Or maybe the motor controller has actually failed, that is certainly possible after such a long service life.

I agree with you that P0A84 is pointing to the root cause and not to worry about P3000, that is just logged by the hybrid vehicle ECU to show that the traction battery ECU is reporting a problem.
Good luck.

 

Patrick,

As always. THANKS!!!!!! You rock. The resistance thing was also were I am leaning as well. One VERY LARGE possibility I forgot to mention is the Grid Charger that was added. It is wired into the cooling fan assembly so that when the battery is grid charging the blower runs to keep the battery cool. There could easily be something in this wiring that is pulling the voltage down for the cooling fan. Remember I accidently dropped the Grid Charger connecting plug in water that was pooled in the spare tire area and caused the ground fault DTC to show up awhile back.

Having this additional wiring pretty much eliminates taking it to the dealer to have it looked at because they will just say replace the fan, replace the HV battery, replace the ECU... replace replace replace ... LOL. So I am kind of stuck troubleshooting myself which I really don't want to do but have to.

Thanks again, I will keep you updated.

Chris

 

Yes, the first step would be to get rid of any third-party modifications and wiring, then see if the problem remains.

 

The grid charger box should not be left attached to the harness when it is not in use.

 

EricBecky,

The grid charger box sits on a shelf in my garage when not in use. I actually purchased the Amphenol plug to cover the end of the connector to keep it safe. I didn't realize my spare tire area was filling with water. The plug got into that slightly and got wet awhile back and threw the ground DTC, don't remember what the actually code number is. So I moved and fixed that, it is up and safe now.

The below picture is off the patent pending controller for the grid charger. I removed the purple/purple, green/green wires and connected them directly to a terminal strip. You can see it in my left hand. Anyway this didn't help and the problem is actually worse now?



I completely removed the cooling fan assembly to clean it and check it out better etc... etc... I even tested it with a 9 volt and it runs but now after reconnecting the motor and taking the grid charger control out of the system the motor doesn't run at all. On TechStream it shows 0.0 Volts and soon generates the DTC's I mentioned within a few seconds of beginning the test? Even at Full Speed of 6.

The resistance across the motor is 1.1 ohms which seems ok to me. Not an EE so not 100% sure but the motor seems ok. So now I am not sure what to test next? Might end up having to put it all back together and go to Toyota anyway it seems.

Any thoughts?

Chris

 

Or you could download the relevant repair manual pages at techinfo.toyota.com as there is a lot involved in the troubleshooting process.

 

Patrick,

I signed up for the 2 day access and looked at the POA84 troubleshooting. The cooling fan relay is now checking as bad. I don't know if that was the whole issue or not but now I know I at least need a relay? Going to try and found one of those now.

Thanks,
Chris

 

Hi Chris,

Use an ohmmeter to determine the relay coil terminals vs. the switched terminals. Then, apply 12VDC to the relay coil terminals (you should hear the relay click) and measure resistance across the switched terminals (should be 0.5 ohm or less, after you account for resistance in the ohmmeter test leads), to verify whether the relay is bad.

 

Patrick

I did. 163 ohms across 1-2 so I know its bad. Trying to find the part# now so I can look for it locally and maybe avoid Toyota.

Chris

 

Relay contacts 1 and 2 are for the relay coil. If you measured 163 ohms across the coil, that is OK.

After you apply 12VDC across 1 and 2, then measure resistance across 3 and 5.

 

Patrick,

The repair manual says across 1-2 should be less than 1 ohm? Above 10 ohms for 3-5 without power on 1-2 then below 1 ohm on 3-5 with power. Step 11 I think it is.

Chris

 

My copy of the repair manual indicates the reverse. Anyway, apply 12VDC across the terminals that measure 163 ohms and see what happens. If the relay clicks, then measure resistance across the other pair of terminals while the relay remains energized.