Hello Everyone. Happy New Year! I have a Prius 2005. In the past, I replaced bad cell 2 times, no problem except last time was around Nov 1st, about 2 months ago. This time I bought 2 used cells removed from 2012 Prius . The Car ran fine but next day, the warning came up and nothing is working, wont start up. I ran diagnostic, it said the negative side hybrid relay stucks closed. I opened up the battery, and I checked the function of all relays. I found one of the temperature sensor wire is broke right at the edge of the sensor. I think I broke it when I accidently dropped 1 cell to the floor from 3 feet above the ground. I resoldered the wire (but i did not check the function of the sensor). However, fixing the sensor doesn't help. I was thinking the car worked fine before until one cell went down to 6.2 v , other cell to 7 v. so it must be the batteries I installed are incompatible, therefore I ordered the 2009 used battery. After Installed 09 batteries the car worked fine until yesterday (almost 2 months), the triangle came up again. I diagnosed and the code said bad hybrid battery, needs to be replaced. However, the car still running normal except the warning light. I opened up and replaced the relay for the negative side of the hybrid which diagnosed bad 2 month ago. I Checked voltage on all cells, they are all over 7.5 v. My 12 volts battery also replaced from dealer few months ago. I cleared the code and test ran. I noticed the battery indicator full charged but suddently went down quick to 3, 2 bar then the warning light came up, then it charges again, but i noticed intermittently I went down then warning pops up. Does anyone have that problem before? The car still run with the warning on. I am afraid to run long test and just around the block to find the problem. Please help!
Here is the update. Yesterday, i drove around the block until the car died. I touched the battery pack to check the temperature OK, Fan was running OK. I opened up the battery and check all cells. I found all the cells are 8 volts or more, except 1 cell is 6.5Volt. I replaced the bad cell but did not have a chance to start the car until this morning. The Car started up with warning light, I diagnosed, Error Temperature sensor..see picture please help.
If you're lucky, you've successfully repaired the failed module but didn't connect all the temperature sensor wires back to the pack. IIRC, there are three but the one(s) underneath are, of course, very hard to check. Or it could possibly be that one of those wires is broken. GOOD LUCK!
Here is the Final update, hope to help someone who has the similar problem in the future... I looked up the error code "temperature sensor circuit A is high" meant "High Resistance". When the circuit is open the resistance is high. I opened the right side end bracket, using the small mirror and small tweeter to pull out the sensor without removing the battery. the wire was broken but still attached to the sensor by the shrink tube. i resolder the wire. The problem is Fixed. No more warning light. I cleared the code. Test drive all day yesterday, no problem. Thank you.
Hi Joseph, I’m glad you were able to fix the problem! After reading this thread, I’m confident I have this same issue. When you say you soldered the sensor wire back, are you referring to one of the two green wires with white stripes on them? Both of these have come off of the little yellow plastic rectangular shaped thing connected to the bracket. But, I can’t see how to solder it back on.
If you are unable to repair the wiring there may be a Priuschat member who is willing to sell or give you replacement wiring from a recycled Gen 2 pack. There are a few members who are in the business of selling packs with new modules and/or rebuilt units. Texas Hybrid Batteries, ericbecky, and strawbrad are a few of them. Best of luck.
Have been having similar issues with sensor, the wire was pretty much gone for a 1/4 inch or so and I used some fine copper wires to thread it together. But resistance is very high on it. Was going to get some new wire and sensing head to try to make a better connection. Considering using gold plated eyelet/head but not sure what size the sensing wire is..anyone know? Looks like sensing wire is 22 gauge. Gold plating looks like a poor option due to the higher voltage. Copper foil may work fine.
