Pinout Needed 99 4 Door 4x4 ECU/PCM

I need the pin out to the ECU/PCM so I can trouble shoot some problems including B1S1 O2 getting stuck at .449 volts and not moving, pinouts for the electric fan control from the PCM, and to try to figure out this damned fuel gauge vibrating needle thing.

Any readable schematic would be great.

You mean these?

Are you saying the scanner shows a lack of o2 sensor activity and it just reads .449 all the time? Or is the reading an average reading not being specified as such. The computer is supposed to be able to tell from a lack of up/down activity and throw a code at you. You may not have any choice but to send the I/P cluster in for repairs to replace that fuel gauge.

sunlitcomet said:

Are you saying the scanner shows a lack of o2 sensor activity and it just reads .449 all the time? Or is the reading an average reading not being specified as such. The computer is supposed to be able to tell from a lack of up/down activity and throw a code at you. You may not have any choice but to send the I/P cluster in for repairs to replace that fuel gauge.

Click to expand...

The O2 reads fine, then just freezes at .449
Yesterday it threw a code p0134
450 mV is baseline voltage, so I am guessing at a bad wire, pin in the connector (at O2 or PCM) or bad PCM.

It happened a few years ago when my dad owned the truck and I could make it read normal by grabbing the O2 wiring harness and tugging on it......just sucks because it is burried in the back of the motor. I am going to check to make sure the pins are not spread in the connector.

As for the fuel gauge, I am going to check the 5 volt reference to make sure its good and see if there is any ac voltage present like interference or something.

Thanks a bunch for the pinouts!!

---------- Post added at 02:07 PM ---------- Previous post was at 02:00 PM ----------

You happen to know which pins get turned on for efan control and which is which and what connector?

Your talking AC ripple. So far I don't think anybody hear with the buzzer has found evidence of ac ripple yet just a screwed up gauge.

The only e fan that was used on I think on heavy duty cooling systems. the 99 pcm had an electric booster fan output from the factory. Black bear tuning has a way to activate and reprogram that pin( or it may have been one of the unused ones that was) to get an electric fan for primary cooling. Is that what you were looking in to. the factory booster fan active pin #9 c4.

sunlitcomet said:

Your talking AC ripple. So far I don't think anybody hear with the buzzer has found evidence of ac ripple yet just a screwed up gauge.

The only e fan that was used on I think on heavy duty cooling systems. the 99 pcm had an electric booster fan output from the factory. Black bear tuning has a way to activate and reprogram that pin( or it may have been one of the unused ones that was) to get an electric fan for primary cooling. Is that what you were looking in to. the factory booster fan active pin #9 c4.

Click to expand...

Yeah, pin 9 is for an aux fan.

I have 05 Escalade fans I want to add, but I need two pins pins to activate, one for high and one for low speed. I will then tune with HPtuners that I am going to buy next week. I just want to make sure it can be done. I need to know which pins can be activated and if HPtuners can control them in their tune.

Use BB Tuning instead (won't regret it)and they can get you the harness as well.

---------- Post added at 02:51 PM ---------- Previous post was at 02:48 PM ----------

could also get a fan controller from flexilite or Painless performance(just announced).

---------- Post added at 02:52 PM ---------- Previous post was at 02:51 PM ----------

Both are variable speed with overrides available.

After about 5 hours of research, it appears that the 0411 swap is the only way to go. Of course then I have to buy EFI live to get fan controls. Not to mention I would need the pin conversion schematic from somewhere for the 4 to 2 connector setup.

where is the pin for rpm ? i need to tap a rpm signal wire from my tunner to a98 tahoe ecu anybody got any idear?
tachometer______crankshaft sensor
thanks sunlitcomt

again with more clarity, what do you mean by "from my tunner to a98 tahoe ecu".

i am trying to lean out some fuel and retard some timing if possiable.

apexi neo which is the tunner(it can modify the signals from different sensors) need to be connected with wires into the ecu

there are 8 wires from the neo which needtobe connected with--------- ecu wires :
2 ignition power (red and red white)------tap into #9pin white ign wire from wt conector
2 ground(black and brown)---------tap into # 4 pin bk ground wire from white connector
1 rpm(green)-------------tap into # 31pin yellow crank signal wire from blue connector
1throttle signal(gray)------tap into #tps dark blue wire from red connector
1airflow (hot wire type maf) and pressure output(yellow) connected to ecu
1airelow (hot wire type maf) and pressure input(white) connected to neo

hope this is right

i just saw a youtube video on that thing. BURN THAT ***** TOY RIGHT NOW!.
you dont screw with these engine with something like that. you will just create problems. Get your self a jet tuner or a blackbear perdormance tune(vendor here on the site.).

You are seriously going to cause some damage with that thing. you NEVER EVER try to modify the actual reading that come from sensors.