2003 Prius Stuck between 2 coconut trees for 3 months now, Need some help!!

But seriously, do you have at least 2 keys that will start your car?
If you only have one you should get another ASAP and keep it in a safe place.

If you need a 2nd key Pmail me, I can get one cut by VIN, mail it to you, then you can mate it to your car with the "chicken dance" procedure .... assuming you have a working master (not valet) key.

 

Speaking of keys. I bought my car with one key and had the dealership make another key for me. Both keys have the black plastic. The valet key is gray correct? When I bought a blank key and had it cut, it will only open the door. I tried the "chicken dance" procedure and cannot get the key to start the car. Going from memory, I thought I read about the memory bank for the keys can only hold three key codes. I thought about clearing the memory, but no one is specific what it takes to start over.

By the way, upon purchase the one key given with the car will not open the trunk. The key from the dealer will not open the trunk either. Do I have a valet key? Why will the car ignore programming more keys?

 

Awesome pics. I can't believe you resurrected that thing. Good deal.

 

I remember reading elsewhere on here that a difference of greater than .1 volts +/- can cause that. I know in the battery rebuild threads that others have balanced all cells when putting in replacement cells.

 

The diagnostic manual reports a code is thrown if the voltage exceeds 0.3V. But a voltage difference of 1.2V or larger means a cell, there are six in each module, has failed.

The fan comes on because a failed cell becomes a resistor. It generates heat when a charge is going into the battery and a discharge is occurring. It is unrecoverable.

We prefer to see 'balanced' modules:

1. same or similar Ahr capacity - a weak module will have a greater voltage swing than a strong one. When (or if) a weak cell ever sees a reversed voltage, it fails, permanently and becomes a resistor.
2. same state of charge - a module at say 30% charge in a pack of modules with 60% charge can easily suffer a reverse voltage which fails it permanently.

Rebuilding a traction battery can be done but works best:

1. Inventory of more than 38 modules - so the weakest ones can be culled
2. Equal charge mechanism - there are several ways to make sure the modules start at same SOC

It can be done but it is not quick. Always remember, 'heat is the enemy.'

Bob Wilson

 

Your Prius monitors module pairs so it is the sum of two modules that must match the other module pairs to avoid alarms.

Getting all of the modules to independently match is better for a longer lasting repair.

Yes, and they should match as well.

Try to obtain a hobbyest battery charger/balancer to work on the modules. I use SuperMate DC6 units and a 12v DC source (Both obtained on eBay for about $35 for the pair). One of these together with an inexpensive digital voltmeter can do whatever is required, multiple DC6's speed up the process, but remember to keep clamping pressure on any module being charged or discharged as the sides can bulge due to internal pressure. There are multiple discussion threads on the HV battery re-balancing process.

A scanner is useful when you want to monitor the car without disassembling it.

There are Gen1 modules on eBay, but their condition varies. The Gen2 and Gen3 modules are better ones, but you need to use all modules of the same type (The Gen3 modules were improved again in the 2012 model year) as their IRs are lower in the newer designs.

There are great discussions on Gen1 Tranny fluid in the Yahoo "Prius-Technical-Stuff" discussion group led by Bob Wilson.

There are ones available on ebay for a couple of thousand US dollars

JeffD

 

Hey Paul,

Does that mean you would also be able to get a valet key cut by VIN? My situation is the car came to me with only masters. That's a lot better than the other way 'round, and I've had another one cut for safekeeping off-site (at the local hardware, just by copying the cut of my master) and I've programmed one as a sub, but I simply don't have any key that's mechanically cut as a valet so it won't open the trunk (and I've never been able to figure out what the difference in cut ought to be, not having the two to compare).

It might be nice to have at least one correctly cut valet key. (I even have an uncut blank already ... I bought two blanks back when I had the extra one cut).

-Chap

 

Remember that the ECU reads the sum of two battery module voltages and in use there can be a drain/charge current of up to 100 amps for short periods. If there is any significant difference in Internal Resistance, a code can be set.

JeffD

 

It might help if you take a quick look at the Wiki page on NiMH battery:

What happens is if two modules have different State of Charge (SOC), say one it on the upper 2/3 and the other on the lower 1/3, as they normally discharge, the one on the lower 1/3 will "drop off the cliff". Its voltage will drop so fast as to exceed the 0.3V threshold for a fault but more importantly, it risks suffering a "reverse charge." A "reverse charge" is normally fatal.

In your ordinary driving, you can't see what the voltages are 'in operation' which is where a Prius aware, OBD scanner pays for itself. The scanner can monitor the "highest block" and "highest voltage" and the "lowest block" and "lowest voltage" while the car is in operation. When these go bad, the scanner shows you the problem and you can then correct the fault.

This is called balancing the SOC, one to two things that need to be balanced.

The other is balancing the Amp Hour (Ahr) by using modules with the same storage capacity. If one module has a lot of capacity, its voltage won't swing much in normal operation. However, the weakest one(s) will. Again, the Prius OBD scanner lets you find out what is going on.

But you are on an island with limited resources (although you have yet to discover structural bamboo!) So what to do:

CONTROLLED DISCHARGE

Set the parking brake (or block the tires.)
Start the car and let it run until the engine stops by itself.
Shift into "N" - this inhibits further charging of the battery and keeps engine off
Turn on every electrical accessory: lights on bright, fan on full, A/C MAX if working, otherwise just fans, cabin lights
Survey the module voltages every 10 minutes or so, keep a log

When you get a code or the module voltages begin to approach 7.2 V, shift into "D" and let the engine recharge the traction battery.

FORCED CHARGE

Set the parking brake (or block the tires.)
Start the car and let it run until the engine stops by itself.

Hold foot brake and floor accelerator for 1 minute.
Survey the module voltages and keep a log.

Repeat above until it will no longer add charge or the error code comes back.

HEAT IS THE ENEMY

Charging NiMH batteries is exothermic, they get warm. Heat weakens the plastic case, increases the internal pressure, and can lead to a seal-leak of gas and electrolyte. Do everything you can to avoid heating the traction battery. But in this case, you are trying to diagnose a problem.

The modules are number 1-38 with 1 being adjacent to the control electronics. If you have the time and resource, check the module temperatures too as this can give a clue to the weakest modules (they get pretty hot.) Relative temperature (aka., finger test) is OK but follow-up with a real measurement if you can.

Bob Wilson

 

That depends on how much current the load drew during the test. Read the battery voltage and load current while under load, then read the battery voltage after removing the load and then you can calculate the Internal Resistance: (Vunloaded-Vloaded)/(load current)

Perhaps under heavy acceleration/deceleration.

I rebalance all modules using my DC6. The down side is that it takes a while to do all the modules (28 for me, 38 for you) as you need to discharge/charge each one 2 or 3 times and the 5w dissipation limit of the DC6 makes it take a while. The up side is that you not only increase the capacity of each good module back to close its 6.5 amp hour rating, you also get a measurement of each module's capacity so that you can put together a matched set. rebalancing is getting all 6 cells in each module back near the same SOC and extend the life of the module.

Bob has experience with the Gen1 modules, I have only dealt with Gen2 modules.

JeffD

 

You'll like my next project . . . a Zener and load resistor as a shunt load to get the modules to a constant voltage level.

In this case, there is a risk (the smoke could escape) approach. Remove the buss bars and wire all modules in parallel. Then put a load, say a tail lamp light on to bring them all down to a know, low level, say 7.2V.

Remove the load and put a charger on and bring them all up to no higher than 8V.

Now remove the parallel wiring and reattach the buss bars taking care to properly torque all nuts and NOT break the sense wires (18 of them??)

Bob Wilson

 

That should work with no problems Bob.

 

I have the parts but have not built my dual-stage charger. I would prefer NOT to experiment with someone else's car. For the curious, this is an Alabama shunt regulator:

• 8V Zener and thermistor in heat-shrink
• Zener in series across each of the 38 modules.
• thermistors in parallel as input to constant current circuit
• 70V, 1A and 0.010A power supply
• With cold thermistors, power supply provides 1A charge current
• First 'hot' thermistor, reduces current to 0.010A

The 'hot' thermistor is because the associated Zener is conducting current. Wire-ORed, the first hot Zener clamps the current to a low value, so the Zener won't burn out and the rest of the modules will continue to charge. In reality, as the Zener cools, the thermistor will become more resistive and the constant current supply with conduct a little more. Thermal equalibrium will be achieved. As more and more Zeners begin to conduct, the constant current supply will continue to reduce the current. After a little circuit tuning, it should reach a point where the Zeners are warm, the modules cool, and all modules at an equal, safe, maximum charge. <GRINS>

But this is not something that must first be done in my lab. Done badly and your battery could become an ugly, toxic mess. You really don't want to pioneer this technique.

Bob Wilson