Midnight F-117A

90 miles ago I had to replace the knock sensors. In the process I broke the MAP sensor which was replaced later then the green wire going to the MAP connector came out so that set off a P0107 code before.

Replaced the connector and all was good until 90 miles later the SES light came on and I was like wtf now!

It happened when the engine was almost at operating temp.


Scanned it and it gave me P0412 which is the 'Secondary Air Injection (AIR) Solenoid Relay Control Circuit'

I erased the code and it came up again on the way home. So last night I tried to troubleshoot the AIR system by doing these:


Checked the AIR PUMP fuse, it's good. Not blown.

Ops checked the AIR Sol relay and the AIR PUMP relay, both good. Both makes click noise when engerized and the multimeter shows continuity thru the relay when engaged.

Swapped relays with the HORN and the FOG lights relays (both same part #'s as the AIR SOL and AIR PUMP relays)
No fix.

Jumped the AIR PUMP relay socket and the air pump turned on, disconnected the hose and no air was coming out (due to AIR SOL still closed) works as it should with the AIR SOL not engerized.

Jumped AIR SOL, heard a click noise everytime it's engaged.
Jumped both AIR SOL and AIR PUMP, pump runs and air comes out of the hose.
Ops checked good.

Disconnected the air hoses to the check valves and removed the driver's side and checked for flow, it flows from the hose into the header but not the
other way around which means it's good.

Did the same to the pax side, found this one more restrictive by "bleeding" a small amount of air from the hose side but none from the header side. I attempted to clean it out with WD-40 which helped a lil but not enough to match the driver's side check valve spec.

I ordered a new one and it will come in tomorrow which I will pick up on the way home from work.
To my knowledge, air will take the least restrictive path so if the pax side check valve was more restrictive in letting the air through, it would divert to the driver's side check valve with more air going thru it so I don't understand how the pax side check valve can cause the P0412 code to be set.

Re-installed and reset the PCM.
Started it up and waited til the engine warmed up and when the temp gauge was near operating temp, I felt what feels like a electric motor being switched on then shutted off at the same time and the SES light came on 1/2 seconds later.

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UPDATE:

I checked the voltage and continuity on the relay pins:

AIR SOL relay:

pin 87 shows 12V
pin 30 is the air soliend (jumping it makes it click)

pin 85 shows no voltage (PCM grounds it when commanded)
pin 86 no voltage or coniunity (suspect broken wire to hot)

AIR PUMP relay:

pin 30 pump motor (jumping it makes the pump run)
pin 85 shows no voltage (PCM grounds it when commanded)

pin 87 shows 12V
pin 86 shows 12V

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I don't know what else could it be and all I can do is check for continunity between the PCM and the AIR SOL and AIR PUMP relays...

I don't have access to a tech2 scan tool and as per the manual, I can't force the PCM to engerize the AIR SOL and AIR PUMP relays without it.

And the state inspection is due by the end of April, the car won't pass inspection with the SES light set and this code showing.

any tips or advice on what to do?

2xLS1

iTrader: (25)

http://www.gearchatter.com/viewtopic8859.php

Midnight F-117A

Seen it before...

The relay pinout is backwards on this image:
http://www.ls2.com/boggs/dtcs/DTC%20P0412.htm

on the AIR SOL relay:
pin 85 should be 86
pin 86 should be 85
pin 30 should be 87
pin 87 should be 30 (then why did the soliend clicks when I jump this pin if it was backwards?)

same goes for the AIR PUMP relay, it runs when I jump pin 30 so it proves it's backwards.


I'm thinking pin #86 has a broken wire to hot (not showing 12V hot at all times according to the wiring diagram) hence letting the pump run but no air gets pumped into the headers due to the AIR soliend is still closed.
I'm gonna put a jumper on that pin to hot and see if the SES light remains off on the way to work.

Midnight F-117A

found pin #86 has a break to the hot bus. Repaired break and ops check good

Now that SES light better stay off for good!