No start, no communication to OBD2, cooling fans on, ECU offline?

Tiny
ALI MAHMOUD
  • MEMBER
  • 2010 NISSAN PATHFINDER
  • 4.0L
  • V6
  • 4WD
  • AUTOMATIC
  • 85,000 MILES
The original harness was cut up and chewed up from previous owner testing and from rat damage. I replaced the entire harness and the IPDM from a junkyard salvage. I get power and grounds to all connections in the ECU ports except port 119 and 120 which turn on the ECU. I'm getting 0.30volts not exactly 0 volts. Is this a short? Port 109 is getting battery voltage from the ignition switch which I traced back.

I checked continuity from several wires going into the IPDM and I'm getting a continuity beep from a lot of wiring. The headlight, fog light, ac compressor, wipers, all are showing continuity to ground. What is going on here? Do they share a same power source that is shorting?

I am lost with this and frustrated after chasing wires for several hours and rereading power diagrams. Any help is needed.
Tuesday, October 14th, 2025 AT 8:56 PM

4 Replies

Tiny
ALI MAHMOUD
  • MEMBER
  • 3 POSTS
Checked the OBD2 port, DLC pin # 6 and # 14 and got 120ohm resistance. Is this showing a short to the sensors?
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Tuesday, October 14th, 2025 AT 9:04 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
I would double check all of the wiring harness grounds and fuses in the fuse panels,(key on) then I would run the codes to see which system is having and issue. Please go over this guide to help:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

CAN SCAN - https://youtu.be/u-4syLc-ifQ

Does the car not crank over? not run? Please give me more information.
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Wednesday, October 15th, 2025 AT 9:40 AM
Tiny
ALI MAHMOUD
  • MEMBER
  • 3 POSTS
Car will crank for days no problem but ignition and fuel is cut due to no power to ECU. ECU does not get power on pin 119 and 120 which is key on, power on. I get 0.30volts when key is on and 0 volts when key is off. Pin 109 gets power from ignition fine.

ODBII pin #6 and #14 has 120ohm resistance. Short or open in resistance somewhere?

No communication from the OBDII port.
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Wednesday, October 15th, 2025 AT 10:28 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
The port 119 and 120 get power from the ECM power relay and fuse #53 in side the IPDM. With the key on I would check the green wire port number 3 on the IPDM which should have 12 volts. Please let me know.
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Thursday, October 16th, 2025 AT 9:55 AM

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