another no CEL / no start after head gasket (1 Viewer)

Joined
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Is this the right pin to check? Getting no voltage. on the blue / black with ign on.
That does not appear to be a connector on the ECU. The ECU lives behind the glovebox and has 4 grey connectors.
E4 is 26 pin
E5 is 16 pin
E6 is 12 pin
E7 is 22 pin

ECU Connectors.JPG


You are looking for +12 on connector E7 pin 1 with the IGN fuse installed and the key in the ON/RUN position.
It is a black wire with a light blue stripe.

IGN.JPG
 

SNLC

OCD
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Joined
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Boise - Idaho
Not necessarily "no power to the ECU".

It's "the ECU is not in a ready state".

It is a process of elimination. Start with making sure the CEL bulb is good and proceed from there. Rarely do the bulbs fail, D bulb about the only one that does fail with any regularity.

Cheers
 
Joined
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Edmonton, AB
It is a process of elimination. Start with making sure the CEL bulb is good and proceed from there. Rarely do the bulbs fail, D bulb about the only one that does fail with any regularity.

Cheers
Thanks for the help everyone. Yes, new fusible link. CEL worked because I got the 401 all the time on the EGR before taking it down. Will check the right connector this time. Was just looking for the big white plug lol
 
Joined
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Davis County, UT
Thanks for the help everyone. Yes, new fusible link. CEL worked because I got the 401 all the time on the EGR before taking it down. Will check the right connector this time. Was just looking for the big white plug lol
Here's the one you're after (2nd largest grey connector on ecu)
20201008_162450.jpg

Or largest of the 3 white connectors
20201008_162535.jpg


Current flows from ign fuse to white connector to grey connector
 
Joined
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Davis County, UT
how do I do that?
make sure all the black on brown wires going into the ecu have permanent continuity with ground, and make sure the yellow on red wire going into the ecu has constant power. And, if I were you, I'd just double check that the CEL light works. With the key on, connect the red on yellow wire at the ecu to ground. If the light is working, and if there is power at your gage fuse (key on), it should light up.
 
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Here's the one you're after (2nd largest grey connector on ecu)
If that is actually E7 on the ECU, then the FSM has some serious errors. Both the 1996 FZJ80 and 1997 LX450 EWDs have the exact same pinouts and they are called out again in the FSMs.
 
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make sure all the black on brown wires going into the ecu have permanent continuity with ground, and make sure the yellow on red wire going into the ecu has constant power. And, if I were you, I'd just double check that the CEL light works. With the key on, connect the red on yellow wire at the ecu to ground. If the light is working, and if there is power at your gage fuse (key on), it should light up.
thanks.
 
Joined
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Messages
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Davis County, UT
If that is actually E7 on the ECU, then the FSM has some serious errors. Both the 1996 FZJ80 and 1997 LX450 EWDs have the exact same pinouts and they are called out again in the FSMs.
I won't speak to the coordinate for the pin, but the wire in both pictures is the same. Confirmed with continuity test
 
Joined
Jun 12, 2008
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I have had this exact problem and chased it around a fair bit, if you have a multimeter it helps, I tried many many of the ‘is it this‘ recommendations and while it was good to Chad around I did not find my problem until I got a multi meter and chased the current from the battery until I found th fault. In the process I did many slight repairs and replacements if fuses etc and ended up unwrapping and re wrapping the harness which in and of itself does give me some piece of mind
My issue was a splice in the cable where it actually attaches to the alternator, as I also rebuilt my alternator when I did the hg I think I disturbed that wire and the splice it contains. You can look at my post for more details under my name.
 
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Edmonton, AB
I have gone through the e7 connector and have continuity on #2, 12 and 22. Grounding the red and yellow does not produce a CEL.

Should I be checking the same on the other 3 connectors into the ecu? Power at gauge fuse is confirmed.
 
Joined
Jul 2, 2014
Messages
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Edmonton, AB
Well I finally got this sorted out. Printed out the EWD and started pulling the harness apart, checking continuity and power trying to figure this out. Wasnt getting power at the 15 amp fuse on the box so knew it had to be around there. As I was checking continuity I had a ah ha moment and felt like an idiot. I have the photoman bracket and 150 amp sequioa alternator which blocks off one of the fusible links and needs a new fused line straight to the alternator. I went digging through my accessory wiring pile which I was leaving until after the truck was running and sure enough there was my alternator positive line. hooked it up and sure enough it fired right up. FML! but glad its working. Appreciate the help and now have a better idea how to use the EWD.
 

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