1994 Sidekick 16v AT 4x4 4dr virgin ECM Ruby's still there

[fixkick]

I just had a worrisome thought...
Should I test all the inputs and outputs to the ECM before I connect the repaired ECM? I am going to check for grounding wires and continuity. This will help me to sleep better tonight.

so the check engine lamp is dead?  this is first step on all cars, 1989 to now.
the DLC has jumper pin , to make the CEL flash 12 code.  means Im ok.
caps are polarized so must not be put in backwards. (installed)

the inputs are fully protected, no need to worry inputs only outputs can blow up easy, (shorted to 12v yes boom smoked)

how does that happen, well things shorted on the  outputs,
the 4 injectors are 10 ohms  each. 12-17 some books show.

the relay coils (VSV) are about 35 ohms.

see my commented schematic yet?
I guess you have the 4 speed A/T tranny.?
one more output it it as pin a16
O2 heater , not shorted,(common) B23, the heater is 1 amp heater, or about 12 ohms but that is hot ohms, best is to have new o2.
iSC b12.  12 ohms (idle speed controller valve , 1 pin plug mounted to huge 16 plenum chamber top left side just in front of TB.

fuel pump relay a5  ,75ohms (see my links for better answers)
main relay A10 same as above same relay actually. as pump

.
so the NOID acts up?, but it sure can , if cranking mode. like that.  (key does the prime pulse is that the worry seening that odd pulse?)
but look for this on NOID tests only, oddness is all ECU processor controlled. if all 4 act odd that is processor on the ECU. doing that. (all that ) for sure all 4 acting odd.

Noid stuck on, is  shorted transistor, all 4 do not stick on,
noid dead, on one, open  NPN transistor or power wire does not reach this injector as you see power is ganged across all 4 injectors.
one noid weak (dim NOID), bad  injector coil shorts, or bad NPN transistor but surely not ever all 4 do this weak test failed.


that is correct RUBICONs dry out , not looks bad test bad. or weak. they all did that, parked in hot sun and caps hit 200F each ever touch a hot steering wheel on a hot day summer, all doors closed after opening, this damage is cumulative. but now fixed.
the ECU can last for many decades but it is the CAPS that short lived on all electronics just after batteries you do not have in there.
the transistors are not noted to fail at all ,unless and injector shorts are yours reading 10 ohms unplugged?  not 0, but 10. (about  10)

if any relay or vsv coil shorts it can and will blow up ITS transistor that drives it. this is what happens, with old relic none smart transistors seen today.


see pinout page ECU 16v



see bottom of page for ohms relays.



watch out for ganged injection most cars can do that in some conditions , I and not sure on this car, at all . 
Sequential or ganged  injection modes.  just know that it can happen on some cars or at some modes.
take limphome mode as just one example and I asked for code 12 DTC code (means) good if not code 12 that is limphome and I have no idea what limphome does, in TOTALITY.

limphome HITS and effects now,... (ecu sees dead sensors) 1 or more, and tells you via DTCs (flash codes, not 12s)
1: SPARK ADVANCE DEAD.  this alone make rich burn.
2: injectors go full rich, (crude injections) all 4 do that, not just one. (in 1996 this was reduced this side effect saving CAT from damage) (history here)
3: idle controls dead,(hot engine) the hot engine rpm controls are now dead, IAC thermal control is always working and is always off line above 150f. (closed)
4: RPM limits.

this is why DLC is used first to get code 12 or not .  if not code 12 that is bad sensors. (coded 51 excepted for bad EGR)
the ECU does not tell you if sensors are weak that is our job. only dead. (stuck low , stuck high sets DTC error)