Partially fried ecu

[fixkick]

I have a 1997 Sidekick Sport 5 speed. I was attempting some troubleshooting and I believe I broke the circuit that activates the "main relay". I think the tight space where the relay is located caused me to have jumpered incorrectly. With everything in normal configuration the systems that rely on the main relay do not work( no start, no fuel pump prime, etc). If i remove the relay and use a jumper wire everything appears to work correctly, i.e. engine runs, dash operates, etc. Ive tried a new relay that did not help. I think what ever component in the ecu that completes the ground and activates the main relay is inop. My ecu is the hitachi and doesnt match any of the pictures are diagrams Ive been able to find. What component controls the main relay?

by hot wiring that relay you blew up the transistor that runs the main relay coil

hot working computers can get super expensive.



there is no schematics on any sport ECU (inside)
the
all I have is this.
actually there are 2 relays, main and just fuel pump.  J18 enigne's, not cars marked sport G16 are only plastic lables with that name,
J18 wide frame car is true sport.

pin C3 Pink , the transistor is blow to hell. or fuse blown #16 FI relay
or C14 main blown. same reason. or its FI fuse. (blue)

is this a J18 engine,  1.8Liters, with 2 cams? called DOHC? sold in N.Amermica's

here is the wiring.1997 and (96) in 1997 the TCM was moved to the ECU and became the PCM, that day. (does 2 jobs)

https://fixkick.com/ECU/18L/18LiterECU1.pdf


the way to blow up FP1 relay is easy, jump C3 to power or to other side of  PF1 coil boom. black/white to pink boom, or fuse blows if lucky
but the transistor is good for 0.1amps and the fuse is 15amps,  or 150 times more power than that tiny transistor can tolerate .
or pink to blue-black boom blow up ECU.(PCM) same is true for main. C14.

best is never hot wire any car with a computer ,  hard fast rule or go broke fast. (just one slip of finger and kiss off $400 for refurb PCM, or 3 times that from suzuki or more from scalpers due to rarity of car.
use a voltmeter, no need to jump pins, ever.

did you find the FI fuse yet under hood.? right fender box, j18 is here.


if curious C3 has PC traces. and if you follow them you land on a transistor blown to smithereens.
same for C14, different transistor.

the other transistor for main is C14 pin, and blows up the same way for the same reasons. fuse 7 is the only hope if not blowing that up, and 150 times more current than it can stand.
short red to blue and BOOM smoke lets out.
hoping for fuses blown, there are 3 fuses there. if you look. FI, IGcoil, and dome (memory) also they moved FI fuse to engine bay box right fender in 1996. 2 in cab, 1 in bay.