PCM 5V to IAT Low Voltage Causing P0112 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

rripp · 03-20-2018, 11:19 PM

Anyone know what can cause only 3.6v out of PCM to IAT when 5 Volts are required? Tried two different PCM's. Also, what pin number should the tan wire to IAT be in on PCM? Maybe I have it in the wrong pin?

This is an early, 2003, DBW with red/blue PCM.

ls1nova71 · 03-21-2018, 12:07 AM

A 2003 would be a blue/green PCM, are you sure its a 2003? At any rate, the tan wire for the IAT is on the red connector pin 25., with the low reference for it on pin 57.

rripp · 03-21-2018, 12:12 AM

Quote:

Originally Posted by ls1nova71

A 2003 would be a blue/green PCM, are you sure its a 2003? At any rate, the tan wire for the IAT is on the red connector pin 25., with the low reference for it on pin 57.

Not completely sure on the year.

Thank you!

rripp · 03-21-2018, 12:17 AM

Tan is in 26. Can I move it over easily?

ls1nova71 · 03-21-2018, 12:22 AM

Look at it close. 26 should be the control for the #1 coil, no reason that should have been removed.

rripp · 03-21-2018, 12:47 AM

Sorry.

The tan wire actually going to the IAT is from the Blue connector pin 26.

BR3W CITY · 03-21-2018, 09:36 AM

26 on the blue connector is an 02 circuit.

Tan wire for IAT should be pin 25 on the red connector as LS1Nova said.

Who did the harness?

rripp · 03-21-2018, 02:02 PM

I would rather not say who did the harness.

First pic is on the blue connector. That tan wire is the one going to the IAT.

Second pic is the wire you guys said should go there. That is the red connector. I wonder where it goes? Could this company have gotten them mixed up?
Posted via Mobile Device

BR3W CITY · 03-21-2018, 04:55 PM

Awwww c'mon, let us know who did the harness.

That pin 26 on the blue connector makes no sense. That pin is for a rear 02 wire, note the other tan wire on 29 (its for the other side). That pair is the rear 02 low signal.
Nothing on the blue connector goes to iat

rripp · 03-21-2018, 07:00 PM

Fixed. The two tan wires were mixed up.

Thank you guys for the assistance!

03-21-2018, 12:07 AM	#2
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,118	Re: PCM 5V to IAT Low Voltage Causing P0112 A 2003 would be a blue/green PCM, are you sure its a 2003? At any rate, the tan wire for the IAT is on the red connector pin 25., with the low reference for it on pin 57. __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

03-21-2018, 12:17 AM	#4
rripp Registered User Join Date: May 2012 Location: Farmington MO Posts: 78	Re: PCM 5V to IAT Low Voltage Causing P0112 Tan is in 26. Can I move it over easily?

03-21-2018, 12:22 AM	#5
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,118	Re: PCM 5V to IAT Low Voltage Causing P0112 Look at it close. 26 should be the control for the #1 coil, no reason that should have been removed. __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

03-21-2018, 12:47 AM	#6
rripp Registered User Join Date: May 2012 Location: Farmington MO Posts: 78	Re: PCM 5V to IAT Low Voltage Causing P0112 Sorry. The tan wire actually going to the IAT is from the Blue connector pin 26.

03-21-2018, 09:36 AM	#7
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: PCM 5V to IAT Low Voltage Causing P0112 26 on the blue connector is an 02 circuit. Tan wire for IAT should be pin 25 on the red connector as LS1Nova said. Who did the harness? __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

03-20-2018, 11:19 PM	#1
rripp Registered User Join Date: May 2012 Location: Farmington MO Posts: 78	PCM 5V to IAT Low Voltage Causing P0112 Anyone know what can cause only 3.6v out of PCM to IAT when 5 Volts are required? Tried two different PCM's. Also, what pin number should the tan wire to IAT be in on PCM? Maybe I have it in the wrong pin? This is an early, 2003, DBW with red/blue PCM.

03-21-2018, 02:02 PM	#8
rripp Registered User Join Date: May 2012 Location: Farmington MO Posts: 78	I would rather not say who did the harness. First pic is on the blue connector. That tan wire is the one going to the IAT. Second pic is the wire you guys said should go there. That is the red connector. I wonder where it goes? Could this company have gotten them mixed up? Posted via Mobile Device Attached Images

03-21-2018, 04:55 PM	#9
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: PCM 5V to IAT Low Voltage Causing P0112 Awwww c'mon, let us know who did the harness. That pin 26 on the blue connector makes no sense. That pin is for a rear 02 wire, note the other tan wire on 29 (its for the other side). That pair is the rear 02 low signal. Nothing on the blue connector goes to iat __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

03-21-2018, 07:00 PM	#10
rripp Registered User Join Date: May 2012 Location: Farmington MO Posts: 78	Re: PCM 5V to IAT Low Voltage Causing P0112 Fixed. The two tan wires were mixed up. Thank you guys for the assistance!



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