Gen 1 2002 CEL OBDII Code P1636 HV ECU Malfunction

I'm going to give an opinion somewhat contrary to Bob's. NiMH chemistry detests charging at high rates when cold. I expect the car will protect against this, at least I hope it does, and I know 100% for certain that Honda IMA does.

Below about 40°F, charging should be limited to only a couple amps. Charging first thing in the morning in a lot of parts of the country will be a problem. Below freezing, charging should be limited to 650mA.

Optimal charging occurs around 70-80°F as the charge efficiency is near 100% up to 70% SoC particularly with such low IR cells. When charge efficiency is that high, very little heat is produced. When you drive higher than 70% SoC, you start to get more and more heat as you approach 100% SoC. The car will obviously not allow this and stay well within the "near 100%" charge efficiency range, AND it will continually taper the current as you approach max SoC

Heat isn't the enemy. Excessive heat is the enemy. NiMH works extremely efficiently up to about 100°F and even higher. At about 115°F inefficiencies start to manifest themselves.

I understand the motivation to treat them as gently as possible, but they are extremely robust and the car uses them pretty aggressively. IMHO "Gentle" testing may not yield an accurate representation of the SoH of the battery. "Gentle" loads from the car's perspective are 20-30A - these are what I have observed with very "gentle" driving while monitoring with Techstream.

 

Living in N. Alabama, we have different concepts of cold. It feels a little above 70F on Christmas Eve so I will defer to those Nawth of here.

The OP data was in the mid 30s C and that was a bit too warm for my tastes. Closer to 15-25 C would be cold enough for our testing.

Bob Wilson

 

Mid-30's... That's where my temps were on my discharge test. NiMH is really happy around there.

On the Gen2 discharge test, the peak was 48.8°C

Even here in AZ, cold can be a factor.

 

Unfortunately, you needed the IB Main Battery field to capture current. Is the file you attached a .CSV file renamed as ZIP? It appears to be an excel file with an incomplete data conversion. Please confirm. If you did anything with the CSV file, could you post the original?

BLock 16 was on the verge of giving it up at 52%. 13.2V is a "danger zone" level for discharging a 12 cell NiMH, so you probably hit it and the BCM choked it down to < 40% SoC.

 

Drop:
WIN
WOUT
Delta SoC
Battery inside air temp
Aux battery voltage

ADD:
IB Main Battery
Battery Blck Min Voltage
Min battery block no
Battery Blck Max Voltage
Max battery block no

Here's your min/max plot:


Here's all the blocks:



Zooming in:


shows blocks 16, 17 and 10 as the weakest. Most of the rest are in a cluster.

13.29 BLK16
14.09 BLK17
14.35 BLK10
14.52 BLK7
14.54 BLK14
14.56 BLK8
14.56 BLK9
14.57 BLK5
14.58 BLK11
14.59 BLK6
14.60 BLK4
14.60 BLK12
14.61 BLK13
14.63 BLK3
14.63 BLK15
14.70 BLK2
14.78 BLK18
14.86 BLK1
14.97 BLK19

 

That's confirmation!

Doh... forgot the visual...

 

Expect to replace modules:

• Both 32, 33, 34 and one of either 20 or 21

Bob Wilson

 

I have a few gen I modules that are good and from a running car after I sold off my extra modules. if you ever need anything in the future. I am near Carson so I am probably 15 minutes away from you in RPV. For the guys really helpful guys on this forum who regularly contribute to help others (Patrick, bwilson, Keith, etc), if you guys ever need any parts for testing or experiment purposes, you guys are welcome to borrow and use my parts. I have several spare transmissions, a spare motor, several inverters, etc for the gen 1.

I always wondered if a transmission can be paired with an 110v external motor to make a charger for the battery packs...

 

Hello Every 1 i am having a whole lot of trouble fixing my prius 2002 1 gen, its giving me P1636, have tried everything in the book it isnt working pls help out with any positive solution am really confused DIY

 

I have a P1636 i dont know what to do pls Patrick Wong or any one pls advised

 

It's a communications error between the ECU and the HV-ECM. Here's the diagnostic:

You can click it for a larger version. Sorry for the poor scan quality, but the all the text came through. I guess first thing I'd check would be the harness connections at the ECU and the ECM. Might be dirty or loose contacts.

BTW, welcome. You will do better here if you feel free to start a new thread with your questions.

 

Oh heck!