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Lou P
Lou P, ASE Certified Technician
Category: Toyota
Satisfied Customers: 4063
Experience:  15+ years experience in the automotive field on all types of vehicles with access to diagrams and repair info.
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I'm trying to hook a scanner to the car and it tells me that

Customer Question

I'm trying to hook a scanner to the car and it tells me that I dnt have communication also the car shuts of if I put it in gear
JA: How many miles are on the car? Have you noticed any fluid leaks lately?
Customer: 145000 no leaks
JA: What is the make/model/year of your car?
Customer: 2005 Scion tC
JA: Are you fixing your tC yourself? What have you tried so far?
Customer: I have tried to see if I have ground and power on the obd ii
JA: Anything else you want the mechanic to know before I connect you?
Customer: I think that's about it
Submitted: 1 month ago.
Category: Toyota
Expert:  Lou P replied 1 month ago.

Hello, my name is***** and i will do my best to assist you.I am going over your story now and will reply back soon with some info,thanks!

Customer: replied 1 month ago.
Okay thank you
Expert:  Lou P replied 1 month ago.

first off here is the dlc pinout, pin 16 is power, check that with a test light with the key on. let me know if we have power.

Customer: replied 1 month ago.
12.7 yes to power
Expert:  Lou P replied 1 month ago.

ok so you tested the pin 16 to ground correct?

ok, check power to ground to pin 4?

Customer: replied 1 month ago.
I have ground
Expert:  Lou P replied 1 month ago.

ok did you check the voltage when the car was running?

Customer: replied 1 month ago.
Voltage on the obd ii?
Customer: replied 1 month ago.
Okay so 16 has power 14.7 while running
Customer: replied 1 month ago.
But 9 has power at 6.7
Expert:  Lou P replied 1 month ago.

ok, making sure the 12.7 was not when the car was runnin lol

and i am not interested in the other pins at this point, when you hook up the scan tool it powers up correct?

just says no communication when you try to read the codes?

have you verified the scanner works on another car?

Customer: replied 1 month ago.
It powers up and yes it works to other cars. It just says no communication correct
Expert:  Lou P replied 1 month ago.

ok, give me a few min.

Expert:  Lou P replied 1 month ago.

also does the car shut off in drive and reverse or just drive or what?

is this stick shift or auto?

Customer: replied 1 month ago.
It's a stick shift and yes when I put it on reverse or first it shuts off
Expert:  Lou P replied 1 month ago.

ok, so i want you to check the ground on the car, check the ground cable from the battery . to do a voltage check first check the battery voltage from positive to negative post then check from positive post to the other end of the negative cable see if voltage is the same, also how does the engine run at idle? good?

Expert:  Lou P replied 1 month ago.

also, why did you not tell me the car may have gotten struck by lightning? that is kinda important,

Customer: replied 1 month ago.
Voltage is at 12.7 while the car off on the battery
Customer: replied 1 month ago.
Car idles and sounds very loud. Sorry slip my mind
Expert:  Lou P replied 1 month ago.

ok , so lets back up a little, what kind of scan tool are you using?

Customer: replied 1 month ago.
Right now a actron
Customer: replied 1 month ago.
Little after market scanner
Expert:  Lou P replied 1 month ago.

ok, so the actron will only scan the engine control module, i have one of those as well as a quick ref , so lets check the diagnostic line from the obd port to the engine control unit, if the wire tests good and has low ohms then the engine control module is fried, with lightning it can cause all sorts of issues, so how we diagnose this type off issue in the shop is we try and communicate with the modules, if we cannot we check power and ground at the module and also the diagnostic wire, if all check out then the module needs replaced. its pretty cut and dry, once we establish communication we move to the next module, the issue you will have is that your scanner can only communicate with the engine module so without a better scan tool you will never be able to check the rest of the car / . so let me know your thoughts on how you want to proceed. Lou P.

Customer: replied 1 month ago.
I replaced the ecm because it kept burning my ignition fuse and efi fuse. I had a diagnostic tech come and reprogrammed the new ecm that's how I got it to start but he also had the same issue with his big expensive computer he couldn't read any engine codes
Expert:  Lou P replied 1 month ago.

ok, well cmon man, lol, why are you leaving all of this info out, we pretty much wasted the last 45 min.........

Customer: replied 1 month ago.
SORRY ��
Expert:  Lou P replied 1 month ago.

so another thing that can happen is if another module was shorted that communicates on the same data lines then it will kill communication of all the modules, so if we unplug the modules one at a time and see if the communication comes back we can see what module is killing the communication. listen i am great with diagnostics BUT only if i know the whole story, so let me see what other modules are on the data lines and see what i can advise.

Customer: replied 1 month ago.
Once I got the car started I didn't think the whole ecm was relevant anymore.
Expert:  Lou P replied 1 month ago.

at this point you probably checked all the fuses in the car to make sure none are blown correct?

also not sure if you know but there is not just one computer in these cars anymore, so since the engine module is new that is a step in the right direction. now we need to see what else happened. this can be tough with the scanner you have but we can at least see what we can do. let me see what info i can find in the system i use i dont want to waste your time so if i cannot find some great info i will opt out, i am not a scion tech i am a benz tech BUT i am great with diagnosis and have access to info that can help just as well.

Customer: replied 1 month ago.
I have triple checked all the fuses.
Customer: replied 1 month ago.
Thank you for your help
Expert:  Lou P replied 1 month ago.

i can only see one yellow wire from the diagnostic port to the engine module, i cannot see any other diagnostic wires at this point so i can only suggest to check the yellow wire from the diagnostic port to the engine module to see if the wire is ok and not broken, i will opt out and hopefully there is a toyota or scion tech with better info that can help.

Customer: replied 1 month ago.
I would have to r and I the dashboard in order to check that wire