I have a 03 trailblazer and has a exhust leak check egine light was on bit now if i get to like 30 the check egine flashes

fusible link on positive side of battery,it is on the smaller wire on the positive side somewhere,it is a round chunk of rubber 03 chevy trailblazer fusible links Bing images

or ignition control module,
03 chevy trailblazer fusible links Bing images

03 chevy trailblazer fusible links Bing images

03 chevy trailblazer fusible links Bing images

Bad 4wd actuator

know more about toyota but try a speed sensor-trans related-good luck-I know no more about that vehicle-JT

prob a build up in cat converter can cause a back pressure slowing down escape of exhaust gases from engine you can get a catalytic converter cleaner to add to fuel tank ,give it a go as a cheap starting point expect it too take a full tank of fuel before it clears check the instruction on product

i think is the catalitic converter it stok .thake off and cleane it whit a solution for that. and change the oxigen sensor maiby it durty .and give me some news thank mike 66

Code P0171 is a lean oxygen sensor code for bank 1 on your engine. Bank 1 is always the side of the engine where #1 cylider is located.

There are a couple of Technical Service Bulletins (TSB's) that may apply to your problem.

Bulletin No.: 09-06-03-004C
This bulletin covers intermittent problems due to oxidation problems in some of the wiring connectors.

Bulletin No.: 03-06-04-030G
This bulletin outlines repair proceedures for clogged or restricted fuel injectors.

The only other thing I can think of would be a vacuum leak that occurs only in cold ambient temperatures and only affects bank 1. (possible intake manifold gasket or something similar.)

THE LIGHT BLINKING MEANS THERE IS ENOUGH OF A MISFIRE TO CAUSE CATALYTIC DAMAGE I WOULD ADDRESS THIS AS QUICKLY AS POSSIBLE BEFOR YOU HAVE TO BUY A CONVERTER AMONG OTHER ITEMS

check the lubricant in the transaxle, if it is low it will cause the light to come on.

If there an Auto Zone in your area, have the trailblazer scanned for the DTC codes which is indicated by the check engine light flashing. The ECM has detected an issue and needs to be addressed, Auto Zone scan free of charge and can give you the recommendations to addressing the issue with your power train and give you the step by step instruction to doing the repairs. 
Good luck and keep me posted, be glad to answer any more questions yu may have. 

short , loose connection or relay --most likely ---those little green light flicker or come on when generally there is an intermittent short, loose connection or a relay or fuse going to fail soon
and nothing works without a good ground ---one could check if the correct voltage is reaching the cruise contol system and go from there

Just my 2 cents --wiggle the connections --gently ---the cruise control is a complicated sysytem somewhat --you may need another symptom to appear to narrow this down more
but then again --I hate Tow trucks it's a GM --SELL IT Buy a foreign car don't go to ford either

a friend of mine once told me --a 30+yrGM master mechanic that thanks to GM's faulty wiring harnesses and stuff HE will NOT ever want for work and Ford isn't any better --
Get the Toyota if you can that is --unless you are a GM Fan
then sorry my bad no insult intended --
HAWK