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Discussion Starter · #1 ·
Hi Everyone.

Owner of 2002 Subaru Outback Limited 2.5L and 600 miles away from home and experiencing intermittent periods of extremely low power. The low power only lasts a second or two and then gets better, but this seems to be happening more and more frequently as today has gone on.

Started after a very rough ride through the badlands...

Got the codes read at AutoZone - Here is what they found:
P0500 and P1540 - Both related to Vehicle Speed Sensor Malfunction
P1518 and P0512 - Starter swtich low input and Starter request circuit
P0137 and P0138 - O2 Sensor Bank 1 Sensor 2 Codes
P0420- Catylitic effeciency below threshold
P0851 and 0852 - Neutral Switch imput low

Lots of codes and if I was home I would attack it one by one. My goal is to get home at this point with minimal expense/time lost...

It felt like the Cat could have been clogged, so I brought it into a muffler shop and he did backpressure testing on both O2 sensor locations and found no issues...

I am not that familiar with Subaru's (my girlfriends car) and am trying to make a gameplan for tomorrow and investigate some things tonight.

I am thinking to look into Fuel Pressure/Fuel Filter - these didn't pop any codes - can I rule that stuff out at this point?

Next I will learn more about the speed sensor and how that could be causing my issues...Anyone have any input on that possibility.

I am thinking the O2 sensor could not be causing the intermittent loss of power, but I could be wrong?

Anything else I am missing or should be investigating. I can do minor things with cars and plan to try what I can do before bringing it to a mechanic and throwing lots of money and getting stranded here...

Any other ideas, given this information?

Thanks,
Jason
 

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Discussion Starter · #2 ·
Some more information if it will help:

This vehicle has a manual transmission.

No issues with speedometer acting weird...

Thanks!
 

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2000 Outback Limited, Dual Range 5 Speed
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906 Posts
Sorry can't help with your problems, but you do know that if you get it towed it either needs to be flat bedded or towed on a dolly as the AWD system on the manuals can't be disabled and so the center diff will be toast if not towed correctly.
 

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Discussion Starter · #4 ·
Thanks for the tow knowledge...hopefully it won't come to that, but good to know.

Thanks,
Jason
 

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'97 Outback stock - Well she was rolled 7/9/17 coming back from Savannah, Ga and totaled :-( Not I have an '07 Outback - not sure for how long though - would like an XT :-)
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40 Posts
Did they test the battery & alternator for proper strength (battery), and output voltage.

Maybe a bad ground.

Just some thoughts,
T.J.
 

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Onyx, 2008 LL Bean 3.0R and 2017 Honda Civic Hatchback Sport Touring
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My first thought as well. Check the negative battery lead. A poor ground could cause several codes and the chances of all of those things going bad simultaneously are very slim and point to a common problem like a fault in the electrical system. It may be something as simple as a battery cable. Here's hoping.
 

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OBW H6 VDC, Tribeca, XT6
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When you have that many codes it is best to clear them and see which one comes back first.

How many miles on the car?

If you suspect it's the front O2 sensor - you can unplug it and the car should run fine. It's just one electrical connector and easy to get to - unplug it. Might not get great gas mileage but they can run fine without the O2 sensor with no issues. Of course if you had a problem just plug it back in, no big deal.

Ignore the P0420 code and catalytic converter, I can guarantee that's not the issue.

Are lights coming on in the dash - like brake lights, etc? That indicates an alternator is starting to fail and may cause a lot of random codes due to low power availability.

Sounds like the alternator is flaking out. Might have it tested, that's something they can quickly do for free on the car at any auto parts stores. They are super easy to replace too as an added bonus if that was a problem. 15 minutes if you've done one before, maybe 30 your first time.

The front main crank pulley (harmonic balancer) can sometimes (rarely) fail. the outer piece of metal separates from a thin rubber ring which holds it to the inner concentric part of the pulley. so the crank is turning the pulley but the outer part doesn't turn as fast - reducing belt speed and alternator output. It will cause low alternator output and dim lights in the dash coming on that shouldnt' (like brake light, etc). Painting a mark across the face of it then starting the car makes it obvious - the line will end up not straight any more as the inner spins faster than the outer. This is rare, just putting it out there...
 

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Discussion Starter · #10 ·
Thanks for all the messages - woke up the next morning (internet was down in hotel), talked to my mechanic, took it out for a test drive, and it seemed to work okay and so we kept on driving, and driving, and driving (to yellowstone and then back to Wisconsin, 2300 miles after this incident). A couple of things that I observed in all that driving:

- I am not sure when all those codes came about - my girlfriend bought the car with "check engine" flashing and never got them read, so some of those codes could have been there a while.

- Only once did the bucking kind of power loss come back and rear its head and it only lasted for a couple of minutes.

- The car can get up to speed okay and keep it up (75+mph), but there is a pronounced lack of power on any hills - felt like I was driving the VW Westy I used to own. Just no power on the hills and motorhomes were passing us at times and I would have to sometimes get into second gear (these grades were only 6-8%). Also, there were times I was in first and had the foot to the floor with absolutely no power for seconds at a time and the engine never revved. This seemed to happen when I started off very slowly with the throttle and did not happen when I would get into first at a higher engine RPM.

But I made it home and can now take my time and try to figure out what the issue is. Will start by checking grounds since all the issues materialized after a very bumpy 25 miles in the badlands (washboard road) (was also 110 degrees that day).

After checking grounds, will probably change oil, fuel filter, and maybe try some new spark plug wires. Does that seem like the way to start this troubleshooting given all these fact or is there another place to look? I do have a 98 Outback (her winter car) 2.5 that I could swap parts off of to see if a difference is made, but it appears that most things are different between 1998 and 2002...

Sorry for not responding sooner - didn't have internet, was on vacation, and car kept working.
 
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