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· Registered
2012 Forester
Joined
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2 Posts
Discussion Starter · #1 ·
Hello folks!

This is my first post so I will give you some history and details about the current problem I am trying to overcome with my Forester. I have checked everywhere for my issue and after an extensive journey combing through YouTube, Google, and Forums, I have finally decided to throw in the towel.

Background: The Forester is a 2012 with the FB25 engine. At around 168,000 miles, I had to pull the engine to do a valve job on the exhaust side of both heads. I did the usual that comes along with that including replacing the timing chains and the water pump. Everything went well and she is running great right now (currently at 170,XXX miles).

Current Issues: I have to get the car inspected and the Check Engine Light is on. I am using an Actron CP9575 to read the codes. There are 13 in total, I am going to list them all and explained what I have done to try to address each issue. I believe I have a general grounding issue but we will get to that after I list the codes and what I have done for them.

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P2004: Intake Manifold Runner Control Stuck Open Bank 1 (Confirmed)
P2004: Intake Manifold Runner Control Stuck Open Bank 1 (Pending)
P2004: Intake Manifold Runner Control Stuck Open Bank 1 (Permanent)
P2006: Intake Manifold Runner Control Stuck Closed Bank 1 (Confirmed)
P2006: Intake Manifold Runner Control Stuck Closed Bank 1 (Pending)
P2005: Intake Manifold Runner Control Stuck Open Bank 2 (Confirmed)
P2005: Intake Manifold Runner Control Stuck Open Bank 2 (Pending)
P2007: Intake Manifold Runner Control Stuck Closed Bank 2 (Confirmed)
P2007: Intake Manifold Runner Control Stuck Closed Bank 2 (Pending)

Details: I never had this issue/code before taking out the engine. I have pulled off both of the TGV Sensors, turned the key, and they are both working as they should. When manually actuating the flaps with the TGV sensors off, they are not stuck and turn freely. When I did the rebuild, I took extra care cleaning both Lower Intake Manifolds to remove all carbon buildup with the sensors removed. I am thinking this is an electrical issue where the ECU cannot see the state of the sensors since it is giving both a stuck open and stuck closed state for both sensors. I'm not really interested in doing a TGV delete as it seems it too can cause similar issues if not done properly.
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P0420: Catalyst System Efficiency Below Threshold Bank 1 (Pending)
P0420: Catalyst System Efficiency Below Threshold Bank 1 (Permanent)

Details: This is one that haunted me before doing the rebuild. I started off chasing this gremlin by replacing both the A/F Sensor and O2 sensor before and after the front cat. This ultimately led to me replacing the forward catalytic converter with a new aftermarket one. If I am reading this properly when viewing the Actron Code Reader, I navigate into where you can view the voltages of the sensor while the car is running. It is showing zeros across all fields which is leading me to believe that again, we have an electrical issue.
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P0302: Cylinder 2 Misfire Detected (Permanent)
P0304: Cylinder 4 Misfire Detected (Permanent)

Details: The car is not misfiring. I do not know why these codes are showing but before doing the rebuild, the car was definitely misfiring from these two cylinders. Does the ECU in Foresters hold persistent codes like this? I was under the impression that having the battery pulled for over two weeks out of the car would clear codes like this.
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Last night, I decided to apply the last fix I could think of and that was grounding out the engine with 10 AWG wiring. The five points I went to were an alternator bracket bolt, the side of the frame where the negative battery terminal grounds two, both of the intake manifold bolts closest to the throttle body, and underneath the throttle body on top of the bell housing. I tied both the intake manifold bolt straps into the same location on top of the bell housing and from the bell housing, the alternator bracket bolt, and the negative battery terminal grounding location, I ran them all into the side of the frame right nearby Cylinder 2 where there was another grounding strap leading under the frame. Everything was cleaned either with sanding down the surfaces to bare metal or glass beating the bolts and reassembled using dielectric grease. If necessary, I can provide pictures to show the work. When I started the car, I could be lying to myself but it seemed like the CEL stayed off for a moment more that normal but then all of the codes popped up again.

If there is anyone that has any ideas of what I can do next, I would be greatly in your debt. I am ready to cross the finish line with this car, get it inspected, and finally remove the chance of getting pulled over by Pennsylvania's Finest and getting a $100+ ticket.
 

· Registered
2017 Subaru Forester Pzev
Joined
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25 Posts
Check the big bundle of cable connedted to the engine. If not seated all the way and in locking position, it will give all sorts of codes.
 

· Registered
2012 Forester
Joined
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2 Posts
Discussion Starter · #3 ·
Check the big bundle of cable connedted to the engine. If not seated all the way and in locking position, it will give all sorts of codes.
I gave it a shot, made sure everything was firmly plugged back in and unfortunately, it didn't change anything. Same codes. Appreciate the time, beeguy.
 

· Super Moderator
2010 X Limited, 2.5L NA, 4AT. Purchased as the second owner in 2020 with ~126K miles.
Joined
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2,729 Posts
I'd disconnect the battery, disconnect that big connector and spray the heck out of it with electronics cleaner. Put it together and pull it back apart. Spray it again. Do that a couple of more times then put the car back together.

There is also a ground connection down by the ECM for the ECM. You should check that and verify the path to ground through that one, too.
 
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