Who is "Hobbit"?
I'm that loose nut behind the wheel
Background: all tech, all the time
Theatre lighting/production tech
Minor vehicle-hacking over the years...
The Prius brought my vehicle interest out of hiatus
Originally wanted hybrid minivan, settled on this
Absolutely no regrets, absent the 100 MPG box-truck
Grassroots evangelism at car/energy shows
The numbers game -- everyone wants the MPG hints!
There are many internet owner communities
Priuschat, priusonline, yahoogroups, ...
Strong tech/engineering forums, too
Google for "hobbit" and "prius"
My own Prius hacks/discoveries detailed up there
Pointers to numerous other resources
Toyota doesn't provide these
So I did, and it really helps
We will explore all this in more depth
EWD and parts-location became my bible
Very minimal harness mods
No operational mods (yet...)
Driving barefoot helps, too!
The results speak for themselves
"This is a NEW car, right?"
-- great quote from a friend
It's a normal car
Just put it in "D" and drive!
Toyota did a nice job on ease of use
It's a very strange car
Idle-stop, even while moving
(Think "steam engine"?)
Stealth mode, electric-only propulsion
Some unusual controls
An elegant blend of many technologies
whose quirks we will learn about in detail
Brake ECU (ABS)
12V battery, now called "aux"
New parts, green parts
Inverters, DC/DC converters
3-phase electric motors
New electric subsystems
New cooling systems
NHW10 -- Japan only
This is really the first generation
We can conveniently ignore it for now
NHW11 -- "Classic" sedan
First US release, 2001 - 03
We will call this "1st gen"
NHW20 -- '04 and up hatchback
technically, it's the 3rd generation
We will call this "2nd gen"
There are MANY more 2nd-gens out now
May 2007: a RECORD Prius sales month
'01 - '04 starting to fall off warranty
Smart-key fob contains metal key for driver's door
That's the only physical lock on the entire car
1st-gen has traditional key
2nd-gen has the "smart fob"
And "smartkey" isn't just in the Prius now!
It knows where you are around/in the car
Walking away with key does NOT cause shutdown!
Fob slot is just a transponder reader
Similar to company door-access RFID card
Dead fob battery? Not a problem, passive chip
No slot in Camry hybrid, just a magic area on the dash
Myth: New fob needs new ECU
There's a re-authorization method via Toyota
For less confusion in the shop, turn it OFF
All described in the owner's manual!
Valet cards that come with the car
But there's a lot more to it...
OFF -- ACC -- IG-ON -- READY
Like traditional key, but uses button pushes (without brake)
Foot on brake is a shortcut to READY
Unless you're already *at* READY, then it turns off
KOER no longer means "Running"
Key on, engine Ready? But the power LED is *OUT*!
It can start up any time, like a home furnace...
... right in the middle of an oil change?!
Knowing these states is critical
And when/how to best use them
Some test scenarios depend on power transitions!
Each "position" is momentary
All electronic -- it could have been pushbuttons
Separate Park button to avoid mistakes
(although the computer sanity-checks that)
Auto-Parks on power-down
Foot on brake permits leaving Park
Brake light switch therefore MUST work
"Transmission creep" is electric
See NHTSA site for safety rationale
Reverse is electric-only
Neutral is special (yellow highlight)
Half-second hold delay -- a little funky to get used to
In Park: start/rev-up on pedal push
Cranks the ICE at 1000 RPM
Races up to 2400 or so
NOT useful for compression check -- too fast
Neutral: no change permitted
Maintains base engine idle
Fancy footwork to make it run: Brake + Go + N
Sometimes needed for inspections [the Georgia problem]
Beware: cranking sounds like running
It's the whole point of these cars
The customers care, we should too
Independent throttle control
Takes that away from the user
Tracks optimal BSFC map -- mostly...
Pulse and Glide technique
High on the efficiency curve, or OFF
RPM maps nicely to power output
... so why is there no TACH?
Kilowatts vs. horsepower
A hundred willing slaves on a rope?
Learn the dash / controls
And what the MFD (Multi-function display) shows
See what I've added
Learn the states and tricks
Find Neutral reliably
Find the one wrong arrow
Lethal voltages and current capacity
It's all about current through the body
If 60V can kill, what can 300V do?
Semi-standard cable colors
Low: < 30V, red/black 12V type
Intermediate: < 60V, blue or green
High: > 60V, orange
Remove jewelry, watches, phones, etc
Metal objects increase contact surface area
Metal objects conduct high current and BURN
Wear 1000V gloves near ANY live connections
Test gloves for pinholes/leaks
Cat III meters/scopes/leads
Same gear used by electricians
Don't do this
Disables the HV battery pack
Orange color, obvious handle
Rear of car
Driver's side of pack
Especially in any damage/unknown situation
Removing glove outers may help dexterity
2nd-gen handle is a little special
Pull straight up, then swing out and down 90 deg
Reverse to re-insert
Handle *must* do that final click-down!
Part of a low-voltage interlock loop
Basic HV circuit
Usually splits about halfway along
Sometimes contains the pack fuse
1st-gen Prius: no
A backup for welded contactors
Ford uses a rotating plug
Honda uses a switch w/ cover
GM/Saturn -- varies
Wait 5 minutes for discharge!
How do you check??
Sometimes you can't until covers are removed
(This one went swimming)
Look it up, don't guess
Avoid HV cables underneath!
Is it really shut down? Make sure
Disable Smartkey (SKS) as you receive the car
("KEY" button under column should be IN)
Vent all exhaust
It's clean, but not that clean
Brake pressure self-check
Door switches can activate many things
Coolant storage self-check, 5 hours later
OEM sites all have ERGs up for free
Honda: turn off, remove key
Toyota: power down, check for no READY
Ford: power off, discon. 12V, pull service plug
GM/Saturn: pop "disconnect control" switch
Only a couple mention service plugs
Certain fuses/relays are detailed
(IGCT, HEV, etc)
All say: kill the 12V system
Lessons from EV competition rules?
Outside accessible, labeled HV disconnects
When in doubt, look it up
Useful related sites:
Wrote many of the OEM manuals, esp. Toyota
Nice technical overviews of many hybrids
Safe cut zones usually shown
Avoids airbags, HV cables, etc
Safe vehicle stabilization
Cribbing points away from HV wiring
First-responders should be confident
You will NOT be electrocuted by:
touching a crashed hybrid
touching a flooded/submerged hybrid
dousing a burning battery pack
HV systems are isolated
Batteries and relays are in a steel box
Just don't cut any HV wires!
Be careful where/how you lift, too
Airbags/SRS and fuel are more dangerous
Potassium hydroxide == potash == soap?
Flush with plenty of water
Vinegar or boric acid can help
NOT really a HAZMAT situation
it's hard to actually get on your hands!
Remove HV pack and 12V before baking
(a revenue opportunity from body shops?)
Temp above 140F is bad for any battery
Screw through HV pack == car doesn't work
Instant ground fault!
(Yes, it has happened, and nobody died)
Shake hands with electricity
It's fairly routine, really
40% generic repair
Know the car!
Customer confidence will help bring them in
Yes, these are picky/knowledgeable owners
Take note of their MPG averages...
Dealership horror stories are common
Here's our chance...
Maint schedule is fairly sparse
5K: change oil/filter, maybe rotate tires
10K on synthetic?
Brake pads? Hah!
Wrong oil can cause no-starts
This is becoming critical in ALL cars
Use the right fluids, OE where possible
DOT 3 brake fluid (not 4)
Two coolant systems plus one A/T
1st-gen transaxle: type T-IV
2nd-gen transaxle: type ATF-WS
(WS is a good upgrade for Classics!)
Toyota super-long-life coolant, no aftermarket yet
Both fluids are pink!
Don't second-guess the chemistries -- look it up!
Motor insulation breakdown is a bad thing
Make sure 12V/14V is healthy
There's no alternator
IG-ON vs READY for many tests
Inspection mode (don't really need it)
Can't snap throttle from underhood!
(Can't cheat and pull motor wire, either)
CAN bus is unbuffered at DLC 6 and 14
Terminated at ECM and HV-Batt (120 ohm)
Without it you go nowhere; be careful what you plug in
Mastertech 3100 with recent Toyota OE cartridge
Aftermarket isn't quite there yet...
Body ECU: OEM tool only?
Customers may ask for "settable options" changes
Newer and slicker than Mastertech ...
But still has a few issues
New US OEM is called "Techstream"
Ruggedized laptop-based, Wifi straight to Techinfo
Just starting the rollout, only a few deployed
Resetting the "MAINT REQD" light that appears every 5000 miles
First, turn car OFF and change the oil if needed
Avoid overfills. See the "engine" section later on for why
With power on, tap the ODO/TRIP button to get to
the odometer display (not trip A or B)
Then, power the car off...
While holding the ODO/TRIP button DOWN, power on again
(IG-ON is sufficient)
Keep holding the button
You should then see the "reset dance"
Wait until it finishes and returns to the odometer
reading, then let the button up. Done.
Many newer cars have similar procedures!
ECU and relay access
Panels pull straight off, don't break tabs
Sheet metal burrs inside -- ouch!
Major ECUs under pass. end of dash
Fairly easy to backprobe, but watch pin size
Four reboots clears MIL (IG-ON usually counts, but not always)
History codes slowly disappear (# trips)
DOME fuse is ECM keepalive, misc standby
Some nonvolatile memory (notably skid-control)
Re-learn after 12V loss
Power window auto-up
Radio, clock, beeps, MPG average (!)
Fuel map trims??
How to leave the car in Neutral
1st-gen has traditional lever/linkage
Oddly placed, but still PRNDB
Emergency park release under column
2nd-gen is more difficult
Electric pawl actuator, special 3-phase drive motor
Shift to N, then pull the PCON MTR relay
That disables Park, but the car gets unhappy
Do what the screen says: set emergency brake
... then you can at least shut down
Once restored, clear the error state DTCs
'06 and up have valvestem TPMS
Be careful when busting, as usual
Sensor range is ~ 60 ft
Inter-car interference is possible!
Many owners run 'em hard (ahem)
3 - 4 psi F/R diff to match for load
HAND TORQUE please -- no impact
Find the ECUs
Classic park-lock bypass [?]
2nd-gen park bypass and recover
Onto lift and have a look under