When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
quick background on the car
it's a 2001 z06 that was built for a race car.i bought it with no motor or pcm and all the wiring in the engine bay was zip tied to the side.i got the new motor and pcm in and programmed the pcm with the cars vin. car runs great and i've had it tuned.
so here is the problem. when i run dtc on the dic i get 28 tcs no comm. also when i hook my chinese tech2 up and try to communicate with the chassis.it tells me no communication check wiring and ignition on/off.
i checked the volts on the red wire at the ebcm harness (pin in bottom right corner) and it was good.i also called the previous owner and he said the abs was working fine when he pulled the motor. car sat for about 7 years before i got it running.
my main question is would a bad ebcm not allow the tech2 to communicate with the chassis?
anything i should check before i send the ebcm in for repairs?
You GOTTA check more than just power...what about your grounds ??...check these power and grounds !!
1) pin B- (brown)- IGN 3 voltage
2) pin F-(blk/white) - ground-- BODY GROUND- G108
3) pin G- (black)- ground - BODY GROUND- G103
4) pin 21 (light blue)- ABS/TCS class 2 serial data --- YOU CAN CHECK FOR CONTINUITY BETWEEN PIN E AT STAR CONNECTOR 1 AND PIN 21 OF THE EBCM ---NO CONTINUITY = NO COMM !!
**** REMEMBER --NO MORE THAN .3 VOLTS CRANKING AND .1 VOLTS RUNNING FOR GROUNDS !! ****
Thanks I'll check the grounds a other pins when I get home tonight.
Not sure what the star connector is though
2 splice packs that are near the BCM at passengers footwell !!...the connector with the 9 or 10 wires . Just pop off the gray "comb" and front probe the connector and inspect
thanks for the help guys. got home late so i didn't have time to work on it tonight.
aren't grounds usually checked with ohms rather than volts?
4) pin 21 (light blue)- ABS/TCS class 2 serial data --- YOU CAN CHECK FOR CONTINUITY BETWEEN PIN E AT STAR CONNECTOR 1 AND PIN 21 OF THE EBCM ---NO CONTINUITY = NO COMM !!
i'm guessing the wire at pin e at star is light blue?
part of them problem is most of the wiring has been reworked. the engine fuse panel has been moved to behind where the passenger air bag use to be. and from what i see comparing the harness in the car with the harness i got with the motor.the only thing left on this harness is the wires for the wheel sensors,the cooling fans, and ebcm. all the wires for the lights ,horns,etc has been stripped out of the harness.it looks like there are only 3 grounds bolted to the frame and no ground junction like the factory.
this is why i contacted the previous owner to make sure everything was work when he had it to make sure i wasn't chasing something that wasn't right to begin with.
i don't really care if the traction/active handling is working but i would like to get the abs to work.
Hope these help !!...YES, wire at pin E of star connector is light blue...as far as checking power and grounds...just think of it as a bridge...concerning the ground side...the current wants to get back to ground (negative side of the battery...called conventional current flow) by taking the path of least resistance...it’s backing up on the wire you are checking...by hooking the voltmeter leads from battery negative to the ground wire you’re checking you just created a new bridge with your voltmeter...more people (electrons) want to go over your uncrowded bridge than the backed up one on the wire...you DON’T want that !!...you don’t want more than 100mv on your voltmeter bridge !!...this is ground to ground voltage drop testing !!
after i posted last night i found that second vid you posted and watched it.
so pin e at stars and pin 21 have good continuity. when i touch the leads together i get .3 ohms and the wire is giving me .5
pin a and b i get 12.3 with key on and 14.3 running out of both
pin g i check with ohms first and was getting .5 and my chassis ground i was getting .4 with the car running pin g and chassis ground i was just getting -00.0 on volts setting
pin f i couldn't get a reading when checking with ohms i was thinking about trying a splice connector and running a wire to the chassis ground to see what happens
Why are you checking grounds with ohms setting ??...that’s not the the best way to check grounds..,you hook black or red lead to the battery negative terminal and the other lead to the ground you are checking...you are measuring a difference in potential between the 2...you are measuring a ground to ground voltage drop....max .1 volts if the car is running or .3 volts cranking...the cranking is higher because of the high starter current flow through the car when cranking !!...you back probe the ground wire with harness connected.
what i did was i connected the neg. lead of the multimeter to the battery neg. terminal.set it to volts 20 and started the car. without touching anything with the positive lead my metter was reading -0.00 with the - flashing. when i touch the positive lead to the chassis ground it was still reading -.0.00 but the - was staying on and the same thing with pin g but when i touch pin f the - would flash again. so i wasn't sure if i was getting a correct reading
so i turned the car off set the meter to ohms , basically to check continuity for the grounds, and i got .5 at pin g and chassis ground and just the "i" when i checked pin f which should mean that the end of pin f is not getting ground.
need help with 28 tcs no comm
