Car cranks but does not start. code 89 appears on ecu

Yes, it is possible for the ECU to be bad even if it is still providing codes to the OBD2 scanner. The ECU is a complex electronic device and it is possible for one or more of its internal components to fail without affecting its ability to communicate with the OBD2 scanner. In your case, the fact that the codes went away after replacing the #35 fuse and the IAC motor suggests that those were the underlying problems causing the "crank but no start" condition. However, the fact that the car still won't start after those repairs indicates that there is another problem, and it is possible that the ECU is at fault. To be sure, you would need to take the car to a qualified mechanic and have them perform a more thorough diagnosis. The mechanic may be able to test the ECU to see if it is functioning properly. If the ECU is found to be bad, it will need to be replaced. Here are some other possible causes of the "crank but no start" condition in your Lexus IS300: Faulty fuel pump Faulty spark plugs Faulty ignition coil Faulty camshaft or crankshaft sensor Low compression in one or more cylinders Clogged fuel filter Restriction in the air intake system If the mechanic is unable to find any other problems, then the ECU may indeed be the culprit. However, it is important to rule out all other possibilities before replacing the ECU, as it can be a costly repair.

why not post the symptoms first, then ask questions.

its not a ford, is my first guess.
my guess. your engine will not start.?????????
the 4ZE1 engines.
"The 2.6L 4ZE1 SOHC eight valve engine features 120 hp (89 kW) and was available as an option to replace the 4ZD1 on four-wheel-drive models."
i dont think there is a reset. like seen on FORDS. its no ford.

if the engine wont start (right>?)
but cranks, great and fast....
and spark is good on all cylinders, not just one and is timed right.
then it's a fuel problem (guessing engine good i am, foolish i am...)
so does test fuel run engine for 3 seconds, ???? (need a video of it)
yes, ? then it's a fueling problem.
so next is fuel pressure cranking, you must crank it.
(on mine , i cant hear my fuel pump spin cranking, too noisy starter)
but if i stick hose in the gas filler next and mech 2 cranks, i can hear it spin, other cars, its very noisy, like my new chev, pu truck.

if not spec pressure check the voltage to pump cranking
12vdc, cranking, good, 0v bad.., 6 v bad, 8v bad.
see>? the voltage matters,! @pump pins.......
now if no voltage to pump ,then we scan the PCM. (flash codes )
if the PCM (ECU) seens spark missing , even if good or tacho signals bad, or cmp bad, or ckp bad or , TPS stuck at 4v
the ECU CUTS FUEL and some even cut pump.
this is by law, to stop crash and burn as seen on TV, (omg)

i dont like easter egg hunts, why do that to pro help, and free!

the car has an ECU and all have flash codes.
you insert the diagnostic jumper and crank for 5 seconds, and the ECU tells you why it cut fuel. (4/5 cases)
it will not , if spark plugs are shorted etc.
it will not if the TPS is stuck at 4v output. (unflood feature forever)
but will for 4 other failures.
cmp
ckp (if fitted)
tacho pin dead.
ignitor dead.
all efi cars 1988 to now, do that. The CEL lamp blinks. a CODE<
and cost nothing to look, on all cars up to 1995. when the blink codes go dead in USA> forever. (OBD2 tech) EPA laws.

ok, ill guess it cranks perfectly.
fact 1, there will be no fueling unless the ECU is happy.
happy means:

1. ECU thinks spark it good. (it has a pin a1 monitor)
2. Spark is good.
3. Throttle not stuck (TPS errors) wide open throttle.

if spark is good, IS IT? on all 4 ?
then try test fuel, if it runs for 3seconds on test fuel then the cam belt is not slipped, and there is spark.
if it does not run on tests fuel there is no spark or timed wrong, or the cam belt slipped. (very common on zero serviced cars)
if timing is still correct and runs on test fuel then we attack the ECU inputs. and outputs (the single injector)
this all sounds complex and is not
lets play that out.

1. ah dizzy rotor turns , cam belt not snapped.
2. ah, the spark is good but is way off time the belt slipped....
3. The engine runs on test fuel, wow sounds snappy too.
4. ok , i use a NOID light on INJECTOR pins 1and 2.
5. the lamp is good, the fuel pressure , hark , is 0psi or 10. wrong
6. the NOID fails, i then check TPS input voltage to the EDC
7. its good, i find the tacho pin dead. OMG.

http://www.fixkick.com/INJECTORS/89/89-90schem1.jpg

this year car the Distributor makes all spark the ECU does NOT.
but the ECU watches it like a hawk.
if pin A1 goes dead, ECU cuts fuel, ending crash and burn like seen on TV.

ask questions.

It sounds to me like it could be one of a few problems.
1) Incorrect ECU for the car
2) Incorrect wiring at either of the parts you changed or at the ECU
3) Faulty ECU

Start with the easier ones and the cheapest. Check your wiring and check your part numbers and ensure that all of them are for your year/model of car. Also, double check all of your connections from start to finish and ensure that there are no kinks, breaks, cuts, scratches of the wires and/or coatings.

wont crank or will not start.? 2 unique things. no crank always results in , no start (unless you push start the car)
hot wiring the fuel pump relay or any relay in the EFI system , invites
blowing the ECU to kingdom come, bad to the bone that.
I fixed them for 50 years. (electronics controls, so know it !)
you do know its really a toyota right?
what ENGINE? each works different.
my prizm text dump.
89-02
joint venture, GM/toyota with 3 engine used.
1.8L or 1.6L
toy engine, 4aFE, 7AFE or 4AG
open hood look
or use the GM RPO tag
or Use the VIN to find motor used.
for docs?
ebay
search
Geo Prizm factory service manual, Duh?

http://www.ebay.com/sch/i.html;jsessionid=D19D723C2EDB4A9FE12E7C01C0677129?_sacat=0&_nkw=geo+prizm+shop+manual&_nkwusc=geo+prizm+shop+manaul&_rdc=1


does car start with test fuel and run, until the fuel runs out.
do you have fuel pressure, while reading the FSM , way of doing it.
some cars only make fuel pressure, cranking and runing.
other make pressure, for 3 seconds key on, and cranking and running only, and all cars drop pump and injections when ECU sees spark die.
that is why stating which Toyota engine YOU HAVE, helps with diagnosis. and please stop hot wiring your car and learn to use a voltmeter. Ive seen $3000 ECU blown up do to bad mechanics.

Circuit breaker box under the hood. Try replacing that breaker. Seems as though it's weak as heat gets to it.

did you check ignition switch

if the battery was removed wrong it could have damaged the ecu. the ecu does not like the positive lead removing first. even without the ignition being on a little power still goes into the ecu. you might be able to repair the ecu some ecu's in the old type ecus had a fuse on the ecu board it could of just blown this.

ok, any obd code means the sensor concerned is not detected by the ecu, or is way out of range of the normal signal the ecu expects. I would therefor check the electrical path between the sensor and the ecu terminals, it may be just a chafed cable or wire.

For the purposes of the D.I.C. 
LO = NO
HI = YES

Starts here:

PRESS: 
OFF &amp; WARM (red button) together
-the D.I.C. will light up the instrument cluster like a Christmas tree
- the D.I.C. will start diagnostics, as soon as it starts displaying ..

PRESS: 
LO 
- until " ECM " comes up

PRESS:
HI
- until " CLEAR CODES ? " comes up

PRESS:
HI
- press only once
- response will be in a few seconds: CODES CLEARED

you are done ...

PRESS RESET and you are back to normal 

Good Luck and Hope this helps