HAC sensor wiring diagram.. HELP plz..

Cyberguy1992 · 04-24-2011, 08:22 AM

I think they only put this HAC(High altitude sensor) in 86 and 87 supras with the 7MGTE engine... I had to send new wires from my throttle body strait to the ECU and it still hasn't been running right. Now I just found out that the HAC sensor gets an input from the throttle sensor. I know that what ever that wir is it's not hooked up now.

So what I need is a wiring diagram for this HAC sensor.

cre · 04-24-2011, 06:48 PM

The GTE wasn't available in any '86 models (not in any '86.5 models either

). The HAC is present in ALL KVAFM equipped 7M's, it's just been moved inside the ECU on later models. You need a TSRM or TEWD from '87 or '88. Below you'll find links for '87. It has the TSRM wiring diagrams (Not as pretty, but they work).

http://www.turboninjas.com/mk3supra/

I don't recall the HAC getting a THA signal at all. The HAC is a little black box mounted on the back side of the lower glove box support. It's nothing more than a MAP sensor.

I sold all my pre89 manuals some time ago as I seldom needed them for anything which isn't covered in the '89.

Cyberguy1992 · 04-24-2011, 07:49 PM

The HAC dosn't get THA, i'm worried about V.. I'm guessing that V is the same as VC.

Is there any thing else that goes on VC?

The EFI TSRM doesn't show what wires specifically go to the HAC sensor I know E2 is the ground for all sensors but V doesn't even show up on the ECU pin out that I have.

I put this Diagram together and this is my guess. The second diagram (with only the HAC sensor) Came strait from the manual... Just to show that somthing from the HAC does hook in with the throttle sensor and the Air Flow Meter..

cre · 04-24-2011, 08:02 PM

Vc is just a constant voltage signal provided by the ECU to certain sensors... it's a power supply line for lower power devices. Should be around 4.8v with load.

Cyberguy1992 · 04-24-2011, 08:12 PM

Okay... that makes sense for the HAC to need a negative and a positive to come up with its signal...

Thanx

cre · 04-24-2011, 08:23 PM

Are you trying to troubleshoot it or bypass it?

EDIT: If you're looking to bypass it, here's my site with info on MAFT Pro installations and as such info on bypassing the HAC sensor: http://www.fadingworld.com/CRE/Autom...ra/Electrical/ See the GTE install wiring diagram for SD. It's quite easy but for most it's easier to see it than just read it.

Cyberguy1992 · 04-24-2011, 08:54 PM

I'm going to make a new engine harness and I'm just trying to gather a diagram for the '87.. do the newer ECU pin outs have the same exact names as the one for the '87 and they are just arranged differently?

cre · 04-24-2011, 10:00 PM

Look at the diagrams on my site for the '87 - '88 pinouts and cygnusx1 for the '89 - '90. Most are similarly named.... I usually buy an old harness and replace the wires one at a time. Have fun, it sucks!

04-24-2011, 08:22 AM	#1
Cyberguy1992 Stock Join Date: Apr 2009 Location: Illinois Posts: 23	HAC sensor wiring diagram.. HELP plz.. I think they only put this HAC(High altitude sensor) in 86 and 87 supras with the 7MGTE engine... I had to send new wires from my throttle body strait to the ECU and it still hasn't been running right. Now I just found out that the HAC sensor gets an input from the throttle sensor. I know that what ever that wir is it's not hooked up now. So what I need is a wiring diagram for this HAC sensor.

04-24-2011, 06:48 PM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	The GTE wasn't available in any '86 models (not in any '86.5 models either ). The HAC is present in ALL KVAFM equipped 7M's, it's just been moved inside the ECU on later models. You need a TSRM or TEWD from '87 or '88. Below you'll find links for '87. It has the TSRM wiring diagrams (Not as pretty, but they work). http://www.turboninjas.com/mk3supra/ I don't recall the HAC getting a THA signal at all. The HAC is a little black box mounted on the back side of the lower glove box support. It's nothing more than a MAP sensor. I sold all my pre89 manuals some time ago as I seldom needed them for anything which isn't covered in the '89. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

04-24-2011, 07:49 PM	#3
Cyberguy1992 Stock Join Date: Apr 2009 Location: Illinois Posts: 23	Worried about V or VC The HAC dosn't get THA, i'm worried about V.. I'm guessing that V is the same as VC. Is there any thing else that goes on VC? The EFI TSRM doesn't show what wires specifically go to the HAC sensor I know E2 is the ground for all sensors but V doesn't even show up on the ECU pin out that I have. I put this Diagram together and this is my guess. The second diagram (with only the HAC sensor) Came strait from the manual... Just to show that somthing from the HAC does hook in with the throttle sensor and the Air Flow Meter.. Attached Thumbnails

04-24-2011, 08:02 PM	#4
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Vc is just a constant voltage signal provided by the ECU to certain sensors... it's a power supply line for lower power devices. Should be around 4.8v with load. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

04-24-2011, 08:12 PM	#5
Cyberguy1992 Stock Join Date: Apr 2009 Location: Illinois Posts: 23	Thx Okay... that makes sense for the HAC to need a negative and a positive to come up with its signal... Thanx

04-24-2011, 08:23 PM	#6
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Are you trying to troubleshoot it or bypass it? EDIT: If you're looking to bypass it, here's my site with info on MAFT Pro installations and as such info on bypassing the HAC sensor: http://www.fadingworld.com/CRE/Autom...ra/Electrical/ See the GTE install wiring diagram for SD. It's quite easy but for most it's easier to see it than just read it. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar ---> Last edited by cre; 04-24-2011 at 08:30 PM.

04-24-2011, 08:54 PM	#7
Cyberguy1992 Stock Join Date: Apr 2009 Location: Illinois Posts: 23	I'm going to make a new engine harness and I'm just trying to gather a diagram for the '87.. do the newer ECU pin outs have the same exact names as the one for the '87 and they are just arranged differently?

04-24-2011, 10:00 PM	#8
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Look at the diagrams on my site for the '87 - '88 pinouts and cygnusx1 for the '89 - '90. Most are similarly named.... I usually buy an old harness and replace the wires one at a time. Have fun, it sucks! __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
1987 Supra wire diagram	scrid	MKIII Supra	4	04-24-2011 05:42 PM
Wiring diagram?	dannydavi	MKIII Supra	3	04-07-2009 04:18 AM
Diagram or photos how to get interior panel off?	stanley2001	Exterior , Interior, and Detailing	1	08-20-2007 03:44 PM
HLP - 87 fog light diagram	kaves_420	Non-Generation Specific Questions	1	10-28-2006 04:49 PM
Vaccum diagram???	h8z2luze	MKIII Supra	5	08-11-2006 02:47 AM