Not motorcycle related...but could use some help

[dallasb]

Alright so the story behind my problem:

I have a 1996 toyota tacoma. It was throwing an engine code so I did a scan, found it to be a p0450 evaporative filter sensor issue. This doesn't effect the performance of the truck so just cleared the code until I can get another sensor in. I started the truck to make sure that everything worked fine and the code was cleared. The next day I went to start the truck and nothing. I have no fuel/spark/and no ecm scanning ability (says there is a connection issue). The battery is at 12.7VDC. I've checked every fuse and relay on the truck as well and flipped some of the relays around to make sure i didn't have a bad relay. My horn, lights, etc still work. Also I took box off the ecm to make sure that a wire hadn't come lose.

Does anyone have any suggestions on what to try next?

Thanks,

Dallas

 

[Theycallmecrash]

engine and trans? huge factors. also, when the key is turned on, does the check engine light come on or not? i dont mean cranking just power on.

 

[dallasb]

Engine/trans were working great before all this (average 20mpg city). All the dash lights come on like they should. The oil light goes off after about 5 seconds to show that its ready to start.

 

[anrkizm95]

unplug the sensor and see if you have comm,check ground connections.also check other sensors for refrence voltage.

 

[Theycallmecrash]

did some research, the engines use similar wiring, from the computer is a white/red wire that is supplid by a 7.5amp fuse 'ign fuse' behind your left kick panel by drivers feet, from there if goes to the EFI main relay in the engine compartment, assuming fuse is good and you have power at relay and the relay kicks on when key is turned on, that supplies power to the computer and almost all the sensors and ignition system, including fuel pump relay which also powers other things. some where from the ignition switch to the fuse, to the relay, and out of the relay is a short, or bad component. at least this is the circuit i would test first.

 

[dallasb]

Alright I'll look into it tomorrow after work and post what I find. Thanks guys for the help.

 

[uly luigi]

Don't forget the collision sensor, I have seen those trip for no apparent reason, kinda the same as our BAS on the bikes, they can be a booger to diagnose

 

[dallasb]

Would the collision sensor throw a CEL code?

 

[Zeroflat24]

Silly question have you tried jumping it? Sounds like the starter may have took a shit. You can have a bad starter that doesnt click.

 

[uly luigi]

Not sure if it would, but I assume it should,

 

[dallasb]

I meant to get out to work on my truck but today just didn't have enough time. I did find a service manual so at least i can start trouble shooting it.

Zero - i don't think its the starter as it is turning over just fine.

Uly - no CEL codes pop up. As soon as I can get the scanner to connect maybe it can give me an insight of something weird going on

 

[Zeroflat24]

Sorry i didnt read the part about it cranking lol What kind of scanner do you have? does it have the capability of live data? Also when you scan it are you scanning it from the OBD port or the under the hood data port toyotas have?

 

[dallasb]

I was using the OBD port inside the cab.

I finally figured out what happened. I had a broke set of wires that go into a sensor for the evaporative canister. Appeared at one time to have been shut in the hood which broke the wires. It looks like that a short between the wires was causing all the issues. Fixed the wiring issues and everything started up just fine.

Thanks for all your help guys

Dallas

 

[anrkizm95]

pretty common shorted sensor or its wires causing no comm.

 

[dallasb]

Not to be an a$$ but there really isn't anything else than can cause no communication considering that it is electrical. You have sensors/relays/fuses and wires so of course it would be a common fix to find/replace a broken wire. I searched for days looking for someone that has posted with the same issues, I wasn't able to locate anyone who had posted the answer after the problem started. Hopefully if anyone else has these issues they will stumble across this thread.

Thanks again to all that helped diagnose this electrical gremlin.

 

[anrkizm95]

Not to be an a$$ but there really isn't anything else than can cause no communication considering that it is electrical

true theres only about a mile of wire a few hundred connections and depending on the vechicle up to 10 control modules.the most common is a sensor or its connector,ground connection.if you have a code for a sensor and no comm it sure narrows it down