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2011 Outback base 6mt 2.5
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Hey everyone,
Recently bought a 2011 2.5 outback with a 6mt. When I purchased the car it was slow but I figured coming from a tc I knew it wouldn’t be as fast. A month later after changing belts, filters, timing belt and water pump, I added some fuel system cleaner which then just destroyed the acceleration. It would not go up hills faster than 25mph but could do 70mph on flat roads. I plugged into the OBD and had a p0321 and p0302. I also saw that my “actual throttle position” was only at 69% with the accelerator position at 100%. This lead me to a faulty TPS(possibly carb cleaner got in after scrubbing the carbon off). Swapped it, and no joy. Then replaced the PCV valve, still nothing. Hooked up a pressure gauge to the fuel line because I thought it might be starving from fuel(holding at 50psi at idle and under load). Pulled the fuel pump and that all looks good and the tank was spot less. I have no lights or even pending codes after all this. Has anyone had this issue or could help shed light before I just start throwing parts at it? I’m thinking it has to be something electrical and the computer is just unsure what to do. Help me please!!!
 

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05 Xt beatin' to an inch of its life
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Check and reply: key on, engine off, gas pedal 100%=throttle position 100%.
 

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2011 Outback base 6mt 2.5
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Discussion Starter #3
Accelerator pedal registers 100% on the reader and throttle body valve opens wide open.
 

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05 Xt beatin' to an inch of its life
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Accelerator pedal registers 100% on the reader and throttle body valve opens wide open.
As reported to the ecu and on your scantool? Or are you saying that you are confirming it visually?
 

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2001 VDC/SC One of a Kind
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The throttle won't go to 100% with 100% accelerator. We've seen in a lot of logs on the P0420 Diagnosis thread where the TPS tops at 80% when driving and the APP at 100% on electronic throttle engines.

No, there's not a throttle learn on this generation in case someone is thinking that. The ECM learns throttle correction while you drive it.

P0301 and P0302 at the same time indicates something may be occuring with the ignition coil. Check the connector, cables and the coil.

I'm thinking vacuum leak, weak battery, bad grounds and maybe something going on with the brakes as possibilities also, but look at the misfires first.

Look at the MAF feedback. Compare the MAP sensor with the BARO at key on, engine off to make sure they match, then see that the MAP is showing about 6 psi idling and warmed up. Look for leaks between the MAF and heads.

Is the rpm fluctuating at idle?
When was the timing belt replaced last?
 

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2010 Outback 3.6R 2014 Legacy 2.5i 2003 Legacy L special edition (retired to backup)
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+1 for coils

fully warned up MAF should be around 2.5 grams a second at idle. you can use brake cleaner to clean a MAF sensor as it is the exact same chemical used in MAF cleaner...
 

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05 Xt beatin' to an inch of its life
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@cardoc, understood. Just to clarify for my own sake: at key on, engine off, accelerator position and throttle command are not 1:1? Is there no clear flood mode on this model?
 

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2001 VDC/SC One of a Kind
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@cardoc, understood. Just to clarify for my own sake: at key on, engine off, accelerator position and throttle command are not 1:1? Is there no clear flood mode on this model?
Yes and no flood mode.

The ratio can be made 1:1 with a retune of the ROM. Not from Subaru though. You'd have to use Rom Raider or ECU Flash to make the adjustment. It's a regular thing for electronic throttles.
 

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2011 Outback base 6mt 2.5
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Discussion Starter #9
Appreciate all the help from the community. I messed up on the code it was p0223 not p0302. After switching the throttle body it still reads 69%, is it suppose to read 80%? I am seeing 69% from the ecu but visually looking at the throttle body. Will it throw a code if timing is off? Has anyone experienced piston slap with high mileage motors? I am getting 12v reading from the ecu so I don’t believe it is power. Did a vacuum check this morning after it was warm to see if it might be a bad cat, it was able to keep the vacuum so I don’t believe that’s the issue. I am going to try to see if the map and maf are reading close at ideal. Ideals smoothly, no misfires. Thanks everyone
 

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I plugged into the OBD and had a p0321 and p0302.
I messed up on the code it was p0223 not p0302.
To be clear, was there only one code, P0223?

P0223 THROTTLE/PEDAL POSITION SENSOR/SWITCH “B” CIRCUIT
HIGH
1. OUTLINE OF DIAGNOSIS
Detect the open or short circuit of throttle position sensor 2.
Judge as NG if out of specification.


After switching the throttle body it still reads 69%, is it suppose to read 80%? I am seeing 69% from the ecu but visually looking at the throttle body.
After switching the throttle body it still reads 69%, is it suppose to read 80%? I am seeing 69% from the ecu but visually looking at the throttle body. Will it throw a code if timing is off?
What scanner are you using?

Is it indicating absolute, or relative, throttle position?

Does the scanner also indicate Accelerator pedal position?

On my 07, also with "drive-by-wire", with the key at ON but engine OFF, and monitoring both the accelerator and throttle position, the throttle will go up to 100% well before the accelerator is nearing that position.

Here's a graph with the engine off. Note how the throttle jumps to, and away from, 100% when the accelerator passes through ~30%:
491688



When driving, the relationship is more complex, the ECM taking into account a range of factors; it's certainly not 1:1. This is a graph of an acceleration from about 20 mph to 40 mph, showing the accelerator pedal and throttle plate positions, with an auto shift from 2nd to 3rd around line 92 (horizontal axis). Note the difference between the accelerator and the throttle, and at the upshift, the throttle returning to 100% even though the pedal position was not increased. (Also, until the upshift, the fuel system remained in Closed Loop, but with the upshift, went Open Loop until around line 103.)
491685


The 2010+, with CVT, might well be different. If your scanner can read both at the same time, it should be possible to verify the relationship both with the Key On but Engine OFF, and when driving (all the more so if the scanner can record the data in a file that can be shared here.)
 

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2001 VDC/SC One of a Kind
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When I run in to a throttle position code I clean it. I have yet to replace a throttle body on a DBW.

If you had the code prior and not now, then you could have had a bad sensor in the TB. Where did you get the replacement?

Is the voltage at 12V with the engine off or running? Have you checked all the grounds?

Take it for a drive and when you get to where you can accelerate with mid to full accelerator pedal, see what the TPS is showing.
 

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2011 Outback base 6mt 2.5
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Discussion Starter #13
So while driving it will not go past 3500 rpm while in first gear and throttle to the floor. Put a bore scope in and the cat looks good, no melted honeycomb plus the vacuum test looked good. TPS is showing 61% and throttle pedal position is 100%. After clearing the code it is no longer there. The new one is from rock auto. New Denso MAF, new Aisin timing belt kit(marks are spot on before and after install), MAP sensor reading on the car looks good and bench tested with vacuum pump. Volt meter read 2v at -12psi. It does knock really bad around 3k.
 

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2011 Outback base 6mt 2.5
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Discussion Starter #14
So while driving it will not go past 3500 rpm while in first gear and throttle to the floor. Put a bore scope in and the cat looks good, no melted honeycomb plus the vacuum test looked good. TPS is showing 61% and throttle pedal position is 100%. After clearing the code it is no longer there. The new one is from rock auto. New Denso MAF, new Aisin timing belt kit(marks are spot on before and after install), MAP sensor reading on the car looks good and bench tested with vacuum pump. Volt meter read 2v at -12psi. It does knock really bad around 3k. I did install an HID kit since the stock bulbs were so dim and a double din. Could this be confusing the ECU? I’m literally out of ideas.
 

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2001 VDC/SC One of a Kind
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What software are you using? Can it log data and save it, or is it just a viewer?

Logging data over time is better than snapshots or freeze frame data. You can better see the course the engine is taking and what the computer is doing.

A cat doesn't fail due to melting substrate. It fails because the platinum in the substrate gets contaminated or the substrate gets clogged with carbon.

Rom Raider is a software based off SSM and records data and saves it. You would need a VAG-Com cable as an interface.

Did you check the grounding? Conductance is important. You can see voltage in the software but you can't see the ampere flow. Resistance through the ground cables needs to be no more than 0.01 ohms. The battery ampere output need to be àt the CCA rating or higher in order to be effective.
 

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2011 Outback base 6mt 2.5
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Discussion Starter #16
Does the VAG cable need to say Subaru specific? I see some on amazon but some say for Audi, bmw...
 

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The VAG-Com is VW/Audi/Skoda. It also works as an interface for Subaru and Mitsubishi.

You don't need any software that is packaged with it if it comes with it. Just let Windows find the driver for it. Follow the directions on the Rom Raider forum.
 

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2011 Outback base 6mt 2.5
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Discussion Starter #18
Ok this seems like a cheap enough route. Will update on Thursday when the cable comes in. Thanks for the help cardoc
 

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Did a vacuum check this morning after it was warm to see if it might be a bad cat, it was able to keep the vacuum so I don’t believe that’s the issue.
Although that is often used to detect a blocked exhaust, in several cases here, the vacuum test did not reveal a restricted cat that was subsequently confirmed by data recorded while driving at high engine load. That can happen because when revving the engine in P or N (typical when doing the vacuum test) there's little load on the engine. The engine rpm will go up high with far less than a wide-open throttle plate, and less fuel being used, so there isn't the same volume of exhaust going through the cat converter. A restricted converter can still allow some exhaust through without developing significant back pressure, but under heavy engine load and wide-open throttle plate, it might not be able to handle the flow, and the engine bogs down. Here's a couple of examples :

However, that still leaves the question of why the throttle plate position reading doesn't seem to go to 100%, or even 80%, with the accelerator pedal floored.

@Nakakyle Did you try the Key at On, Engine not running, test suggested earlier? If not, then . . .

on the scanner that's shown in your earlier post (what make and model is it?), can you select the parameters that are being shown? If not, then use the same list as in your photos. If yes, then select:
  1. Throttle Position
  2. Relative Throttle Position
  3. Absolute Pedal Position D
  4. Absolute Pedal Position E
  5. Commanded Throttle Actuator
  6. Relative Accelerator Pedal Position
Connect the scanner to the OBD connector. Then with the ignition switched to ON but engine Not running, and the scanner reading the data from the ECM, record the readings including all six parameters; a photo, as before, is fine. Note, this step is with the accelerator pedal released.

Next, move the accelerator pedal down about half way and hold it there; record the readings again.

Then, press the accelerator pedal to the floor, and record the readings.

Post the results.

This is to try to determine which parameters that scanner is reading, and perhaps identify why the throttle plate opening % doesn't appear to go beyond 69%. In part, it could be the selection of parameters. Attached is a list from the FSM showing the parameters that can be available when using an OBD-based scanner. (This is different from the parameter list that's available when using an "ssm" scanner, such as Romraider.) Note that the descriptions for the Throttle and Accelerator Pedal parameters in the attached list are not quite the same as in your scanner. By doing the test, it might clarify which parameters are being scanned and why their levels are what they are.
 

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2011 Outback base 6mt 2.5
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Discussion Starter #20
I ordered the cable in order to use RomRaider and will post pics/data. When at idle/revving to ~2k should I be able to feel the individual exhaust pulse from each cylinder? I can really only feel steady flow. Has anyone tried the dish wash soap to try and clean out possible residue in the cat? We stuck a bore scope and I don’t see anything melted so possibly it could just be gummed up? I could not get the scope into the secondary cat as that one has a much longer run.
 
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