Hi all, first time posting and first time to this board was last week. Have been searching board for solutions to this check hybrid system and haven't found any solid leads yet.

Long story short: have a 2007 hybrid camry I'm working on (not mine). Have reconditioned battery pack (replaced 2 cells myself) but still get check hybrid system.

Long story not short: This car is not mine, it belongs to a friend who received it as a gift from some other friends. The original owner drove it until it started throwing codes for replacing battery pack. Dealer wanted 4 grand so the original owners decided it wasn't worth it and just bought new vehicles (I think they actually had two identical 2007 hybrid camry's!). They gave this one to Jenn and then sold the other I think.

Jenn, drove it until it wouldn't even start. She was a broke college kid so I looked into it and found out you could clean the bus bars and replace cells if needed. I pulled the whole battery pack apart and found one cell at 2.5V and another at around 6.8V. All other cells were at 7.5 or 7.4V. I cleaned all the bus bars and replaced the washer nuts with new ones. I read in another post you can clean the bus bars with muriatic acid. Wish I had thought about that before the hours of cleaning

As best I can tell, the problem with the bus bars corroding is that the voltage probes that run back into the Denso voltage sensor module can't read voltage through the corrosion. I'm assuming this sensor module measures differential voltage between the adjacent cells? Or maybe it measures with reference to ground? Either way I measured around 14V between each adjacent set of probes at the pins going into the connector on the sensor module. I did not load test the cells but I will if I need to (although I dread pulling that battery pack back out now). I did measure about 253 V going into the HV relay assembly once the service plug was back in.

I haven't been able to pull any codes with a OBDLink MX scan tool. I'm not sure if the techstream software will work with that module but the software I've used so far can't get me anything useful. If this scan module won't work with this car I was looking at ones on ebay for around $40 so I can pull codes and get more info.

This car is not in the best shape (interior and exterior) plus it hasn't been well maintained since poor college kid has been driving it for a while (needs tires, brakes, probably all fluids changed). Based on the other posts I've read in this forum, it seems it could have other costly problems (water pump, coolant system, brakes...). She can now afford to replace the battery pack but my advice to her was to let me get it running with the reconditioned battery pack first, then drive it for a while to make sure no other problems pop up.

If anyone has advice on getting codes (especially using the OBDLink MX) or other things to try I would appreciate it! If not, I will order a tool from ebay and see what I find.

Things I have tried: Charged 12V battery, tried jumping 12V battery from another car, reset ECU from scan tool, tried the emergency starting by holding power button for 15+ seconds (does that ever work?). On the MIS, the battery shows as level 1 according to the owners manual (lowest it can go without showing an empty battery). It started out as level 8 I think after a reset and then dropped to level 1. I guess that means it thinks the battery is dead or does it do some kind of load test?

 

Read codes. MiniVCI & Techstream.

 

Get USB to OBD2 cable and down load Techstream online. It's free.
Many of that year cars had Check HS code fixed by replacing battery - the 12V one. It is likely done by now. It's a deep cycle battery and needs DC charger and you can not test it like you test conventional 12V.
With only several cells underperforming, vehicle should still run, only have worse mpg and recharge more often.
If you done everything right, connected everything back right - saw post when fella replaced entire battery and hit the no start just to find after desperate days later - that he missed one connection, then she should run normal more or less.

 

Got TechStream setup and pulled these codes on the hybrid system:

P0A0D - High Voltage System Inter-Lock Circuit High (Current and History)
P0A7F - Hybrid Battery Pack Deterioration (Pending)
P0A84 - Hybrid Battery Pack Cooling Fan 1 Control Circuit Low (Current and History)

The HV disconnect plug is definitely in so I must have messed up something in the battery pack for the P0A0D. Need to look more into that one.

No doubt hybrid battery pack is deteriorating.

The last one there I think may have been the problem all along (besides battery pack dying). I found this: https://techinfo.toyota.com/t3Portal...=1467649768101 which is exactly what I need to diagnose but that page is for 2010 prius. Know of one for 2007 camry?


I'm also getting code C1241 (Low/High Power Supply Voltage) and C1259 (HV Control System Regenerative Malfunction). I've been reading that C1259 can be due to low 12V battery. I had the 12V battery on a charger but need to put it back on and see if these codes clear.

 

Those "C" codes are typical for when you have HV battery related codes. They go away when the "P" codes are addressed.

The interlock must be pushed in, levered up and then slid down to engage the circuit.

This is the diagram for removal:


Step 3 is slide the handle up, step 4 is lever it down and step 5 is pull it out. You need to do the reverse. The sliding of the handle engages the circuit to tell the car the plug is in place rather than just rely on seeing high current.

P0A7F is likely a result of your rebuild. Used modules from ebay are rarely good.

P0A84 dunno.

You can go to http://techinfo.toyota.com and sign of for access - $15 for 2-3 days or something like that. You have full access to the manuals and can download PDFs relating to those error codes for troubleshooting.

Note that if there is a little blue snowflake or "splat" next to any of the codes in the Health check, that means there is detail information. Click on that snowflake and look for the "detail" code. it's usually a 3 digit number, e.g., P0A7F-123.

Some of the basic DTC can have as many as 25 detail codes associated with them.

Good luck,

Steve

EDIT: If you go into the Hybrid Control ECU, you can see all 17 of the block voltages. Look for outliers.

 

Thanks for that info about the "splat". What I see now:

P0A7F and P0A84 are gone now. The blower wasn't plugged in, must have missed on one of the 3 or 4 removals, not sure why P0A7F went away.

Still have the P0A0D. I made sure the HV disconnect plug was firmly seated. When I clicked on the splat and got the freeze frame data what I see P0A0D-350 with all battery block voltages are around 15V except two. See screenshot below.

Since it's saying the circuit is high, the ECU must have something to detect when that plug is removed and that detection must be bad. At least that is all I can make sense of this since the plug is firmly seated. As I mentioned in the first post, I could measure 253 Volts going into the HV relay block. When I removed the HV disconnect, the voltage would drop to 0 Volts.

I did find one post where a guy said he used piercing probes to measure voltage and that those orange cables have a shield which he likely shorted the battery to after piercing. I have normal probes and just measured by touching the bare metal inside the back of the connector. Plus if I had a short all the cells should be dead.

Edit: Found this for Prius:https://techinfo.toyota.com/t3Portal...=1467656303476 so there is definitely a detection circuit for this plug.

Edit #2: "P0A0D-350 is also set if the power switch is turned on (IG) with the service plug grip removed. Confirm the conditions when the malfunction occurred." If that plug wasn't firmly seated this could have been the problem. According to that page, I need to clear the DTC and try again. Will do soon.

 

P0A0D will likely go away with a techstream reset or a 12V disconnect/reconnect.

Without a doubt, you have bad or severely imbalanced modules in blocks 11 and 15 based on those numbers. You will get a battery deterioration code very soon.

A healthy pack will have < 0.2V difference between min and max at OCV or very low load.

My tested/reconditioned pack is typically 0.12V or less. The max I have ever seen is 0.45V, but that was under full throttle acceleration pulling 130A.

 

Well finally got the thing cranked after about 8 months of sitting in the drive way.

I took a closer look at the HV disconnect plug and I could see 2 small terminals sticking out. When I put the plug back in, there was a small white connector that looks like it should fit onto those pins when you close the plug. But for whatever reason, the terminals came no where near the white connector. I used a jumper to short the pins in the connector (after verifying 0 ohms/continuity across the pins in the HV plug), cleared codes, turned of ignition, then turned back on and it cranked up (after a very very rough start no doubt due to old gas).

I don't understand how that white connector is supposed to work with the HV plug. Either I'm missing a part or I did something when I disconnected it 8 months ago.

You can see in the pictures below what I'm talking about. The top picture you can see at the top right the two pins. In the bottom picture the plug is fully inserted and locked but it comes no where near the white connector in the black housing on the bottom left. I pulled the white connector out of the black housing and jumped the pins. I guess for a "permanent" fix will stick the white connector directly into the HV plug.

 

I can see from the picture that you haven't engaged the plug as I instructed (along with pictures). The handle is slid straight down onto that connector completing the circuit.

EDIT: See how he slides it up and rotates it out before removal at 2:30?

You need to slide it down.

EDIT: even better, they show you how at 5:20

 

Doh! That was it. I glossed over details because I knew I had the plug in enough to complete the circuit. I can't believe I needed the computer to tell me to completely plug in the disconnect. Usually I'm the one getting on to people for not closely following instructions. Guess it's my turn this time.

Thanks so much for the help.