# 95 v6 EFI sensor ID help



## Erics_Daily (Feb 18, 2006)

I have a slew of of nagging issues on my 95 2wd v6 and have some general questions if someone doesn't mind volunteering some info. The haynes manual passes over efi related stuff.

1. I took off the plenum to fix vc leaks and saw this connector tied off just laying there. Is to the BPR/EGR and some recall had them disabled? The previous owner only had dealership work done to my knowledge. Its the last connector on the harness before my question #2 sensor











Two other places are plated off next to the TB and am wondering if it is related

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2. what sensor is this? it has the TB coolant lines running through it.











3. I see the sensor labeled AAC valve. It looks like an IAC. does AAC mean IAC or is there an IAC somewhere?

thanks

PS If someone wouldn't mind volunteering the efi diagram for a 95 3.0L HB, it'd appreciate it.


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## zanegrey (Dec 5, 2005)

PM ME UR EMAIL ADDRESS AND I WILL SEND YOU A PDF FOR THAT YEAR...


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## Erics_Daily (Feb 18, 2006)

PM sent. thanks!


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## smj999smj (Jan 1, 2006)

The "tower-like" object front and center is an air regulator. The part behind it with the coolant lines is the IACV (idle air control valve). I don't remember any recalls that disabled anything with the EGR system and EGR-BPT's are vacuum controlled, not electrical. It could just be a harness connector that is not used on your particular vehicle.


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## Erics_Daily (Feb 18, 2006)

There was no EGR on the upper intake. where is it? Again, 2 things were plated off next to the throttle body. whats that about?


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## smj999smj (Jan 1, 2006)

The EGR valve and EGR-BPT valve are on the left side of the engine, located between the throttle body and the IAC-air regulator you have pictured above. There should be an EGR pipe that runs from the EGR valve to the exhaust manifold. Perhaps this is what's blocked off? Going back to post #1, "AAC" means "auxiliary air control" and is often incorporated with the "IAC"...forming the IACV-AAC valve, which is controlled by the ECM to create fast idle during cold starts and maintain idle under load by controlling an air passage.


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## Erics_Daily (Feb 18, 2006)

ok, after looking the schematics zanegrey sent me it seems the egr/bpr are in fact gone and blocked off and the connector tied off was to one of them. i wonder if there was a recall for them and the ecu was reflashed to cancel their input out? sorry for the trivial questions but i like to know where everything is in case it decides not to work in the future.

(direct link pic)

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## smj999smj (Jan 1, 2006)

Reflashable ECM's weren't used by Nissan in 95; they didn't show up until the early 2000's. There was no recall to block off the EGR on 95 Hardbodies nor any other Nissan. The plug was likely for the EGR Control solenoid valve. My guess would be that somebody simply blocked off the EGR system.


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## Erics_Daily (Feb 18, 2006)

thats weird because my previous vehicle would throw a CEL if ditching the egr unless you jumped a resister through it. Gotta love pre-OBDII I guess. Anyways, thanks for the help guys!


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## smj999smj (Jan 1, 2006)

The 95 HB's and Pathy's were the last to use this diagnostic system, often referred to as Nissan's "checker box" system, named for the Kent-Moore "checker box" diagnostic tool used to plug into the large black diagnostic connector and serve as a remote portal to access the red/green LED's used to determine the stored trouble codes. This helped the technical out by keeping him from having to look under the passenger seat to read the green/red LEDs on the ECM. This system came out in the early 80's, IIRC. When it came out, it was "state of the art," but in 95, the rest of Nissan's vehicles were already using Nissan's Consult diagnostic system and the "checker box" system was "crude" in comparison. In 96, both the HB and the new R50 Pathy were using the Consult system. One thing you may want to do is make sure the "check engine light" still functions. Turn the ignition switch "on" (engine not running) and the check engine light should be illuminated. If not, the bulb may have been removed or covered with electrical tape.


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## Erics_Daily (Feb 18, 2006)

thanks for the insight. yup CEL comes on at key-on. sidenote, the exh manifold plug and egr/bpt plates looks professional. thats another reason why i thought the dealer did it.


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