04 GT / P0122 & P2135 Errors

[Jim2013]

Car has gone into limp mode again...will be back in tomorrow for diagnosis...
Running fine for a week as well..
Wondering if the upper engine clean has fkd something...
Any pointers appreciated...

Is the car completely stock with the factory tune?

Edit: Reading some of your earlier posts I see you've just bought the car. I'd get someone who knows how to use a Tactrix cable to download your tune and compare it to the stock tune. I've seen this error previously when the tune is amended to compensate for faulty O2 sensors and exhaust leaks where the throttle position at idle as been changed. The same may also apply to Boostaddict's situation.

Just a thought.

BTW the Subaru expected life of an O2 sensor is 160,000kms so something doesn't sound quite right.

Thanks for the feedback everyone. I'm now paranoid driving the fkn thing.
Car is stock mechanically and program wise / One owner / FSH.
Taken it back to mechanic and it is has TPS error (voltage) in memory.
He took it for a "spirited" drive as he still feels that the engine clean may be responsible.
He's gonna give the o2 sensor the propane torch treatment and take it from there.
Really annoying as the car runs great 99% of the time.
I'll keep you posted.
Jim.

[Jim2013]

My guy has been working on the car all day and has told me he will not charge - which is great!
But the car is now in limp mode permanently and he is running out of ideas.
He can see the issue happen with the computer attached but I think his SW may not be specific enough to catch the exact issue.
It’s getting to the lets go to Subaru, get them to locate the exact cause and then get bent over and shagged in the car park stage whilst they steal my wallet stage....
shit
Jim.

[Boostaddict]

Ive been assured by the tuner that the actual tune is spot on!!

I have been having this issue sporadically , so im pretty sure its not the tune!!

Was the car tuned with the faulty O2 sensor installed at the time?

Yes. But it was tuned through a bung in the exhaust dump pipe. So it should be all good after i have changed the sensor.!!

I must admit that since last thursday the car hasnt thrown the code ( usually within 2 days ) But i get a hesitation after changing gears and getting back on the throttle quickly on 30-50% throttle. Weird!!

[Boostaddict]

My guy has been working on the car all day and has told me he will not charge - which is great!
But the car is now in limp mode permanently and he is running out of ideas.
He can see the issue happen with the computer attached but I think his SW may not be specific enough to catch the exact issue.
It’s getting to the lets go to Subaru, get them to locate the exact cause and then get bent over and shagged in the car park stage whilst they steal my wallet stage....
shit
Jim.

Mate i wouldnt go to bloody subaru as they still wont fix it!

If you are near parramatta / rydalmere go down to Nick @ NRG automotive. He will find it!!

[Jim2013]

My guy has been working on the car all day and has told me he will not charge - which is great!
But the car is now in limp mode permanently and he is running out of ideas.
He can see the issue happen with the computer attached but I think his SW may not be specific enough to catch the exact issue.
It’s getting to the lets go to Subaru, get them to locate the exact cause and then get bent over and shagged in the car park stage whilst they steal my wallet stage....
shit
Jim.

Mate i wouldnt go to bloody subaru as they still wont fix it!

If you are near parramatta / rydalmere go down to Nick @ NRG automotive. He will find it!!

Cheers for the heads up - I'm South / Dolls Point way...
I've given my guy the manual I downloaded from here which goes through trouble shooting TPS errors. But i dont think he's had time to look at it tbh.
I've been on different sites all day and some have fixed it as easily as reseating the connector on the throttle pedal / cleaning out the connector.
From what I'm reading there are 2 sensors which have to operate within a certian range. If either is out hey presto limp mode. I'm still hoping its as simple as a throttle sensor replacement. I'm currently checking the for sales section for parts.....
Jim.

[Jim2013]

Car has been at mechanic for 1.5 days. Had a call from him saying battery was shot and would not turn car over.
Replaced and everything ran fine / errors cleared. 3 hrs later CEL's again ffs!
He has now sourced a second hand throttle body assembly and installed it. Car drove home fine.
He was talking to a Subaru mechanic and he said that it was probably the upper engine cleaner that got into the electrical components on the throttle body.
There is a channel where the liquid may have got in. He did mention that the upper engine cleaner usually goes in after the throttle body / we did it before - Subaru guy said it shouldnt really matter. Have not paid for parts yet as we are trying it out first. Any one have any idea how much the Throttle body assembly should cost - apperntly Suabru want nearly a grand!
Looks like I didnt need the new o2 sensor then after all this - may just leave it in! I hope thisis the fkn end of it!!!!
Jim.

[Jim2013]

Car was running fine for about 10 days when the dreaded Engine light / cruise light re-appeared.
Car struggled to turnover and when it did limp mode came on nearly straight away.
Turned car off re started fine no hesitation - drove 3/4 way home before limp mode came on again.
Luckily I had green lights for about 6km so I just managed to get home at 60kph car died just before drive way - felt like 2 cylinders / was banging like a dump truck.
Left car for weekend and started up fine this week drove to mechanic and read codes / still P0122 + P2135. I have a test throttle body assembly in the car and Im still throwing the same codes as th eold one. Mechanic is pulling his hair out. Im now paranoid driving it with kids in car in case I pull out into traffic and it dies again.
Codes cleared gonna put my original throttle body back in. He now has a feeling it may be the ECU so we are now sourcing a donor to test.
As suggested on the other 04 GT thread I'll ask my mechanic to check that he engine earths are all ok.
Apart from testing every bloody harness is there anything else it could be?
Only bit of luck is that I've found a guy on a US site which is having exactly the same issue / codes / replacement throttle body assembly that did not fix it etc.
He is dealing with Subaru directly and posting the progress....hopefully I can piggy back off it..
This has basically killed the buzz with this car.....
Jim

[Jim2013]

So looks like these faults are very intermittent.
Gonna put my old throttle body assembly back next week as the replacement did not help - I think the idle is rooted tbh.
Car has not thrown a code for a week. I re-seated all the fuses and issue has not happened since. Coincidence probably but my interior light has also started working again - hadn't worked since I bought the car!
To Do:
Check Engine Grounds
Check Throttle Pedal Sensor - Guy I was following in the US who was throwing same codes and had also replaced throttle body assembly replaced this part and his issue stopped.


I wanna tune this fkr so bad but have to sort this error first....

Jim.

[Jim2013]

2 weeks now and car still ok. But Idle is low - 667 rpm not sure how to rectify this.
Still need to put old throttle assembly back inas well.
Guy I was following in the US found the issue to be a loose pin at the throttle body where the harness joins the assembly.
Jim.

[Dropz]

it's a long shot but maybe get a subaru dealer to check your body control module for any codes/ faults. if your interior light never worked and it has just started then chances are something has changed in the body control module or a circuit involving that (its the only thing that controls the light except the switches).

Also check all your brake lights are working, I've seen 2 scenarios where blown globes have caused engine related symptoms.

And have you checked to see your throttle pedal switch is connected firmly, and clean? maybe your mechanic knocked the plug when he worked on it, either with his boots, or when using the OBD2 connector.

[Jim2013]

it's a long shot but maybe get a Subaru dealer to check your body control module for any codes/ faults. if your interior light never worked and it has just started then chances are something has changed in the body control module or a circuit involving that (it’s the only thing that controls the light except the switches).

Also check all your brake lights are working, I've seen 2 scenarios where blown globes have caused engine related symptoms.

And have you checked to see your throttle pedal switch is connected firmly, and clean? maybe your mechanic knocked the plug when he worked on it, either with his boots, or when using the OBD2 connector.

Cheers for the input. Brake lights are fine.
During my “research" I noticed one of the errors codes I had can be caused by the pedal switch being loose. I did mention it to my guy several weeks ago and I think he checked it.
Car is running fine but I want to put my old throttle assembly back in to prove it was ok all along.
Once that's done if my idle is still low I'll take it to Subaru and get them to adjust the timing for me via their select tool and also check the BCM for codes.
On a side note I took my engine cover off a few weeks ago at the same time the errors stopped - wonder if the cover was interfering with a harness..may check.
Cheer - Jim.

[Dropz]

The only harness that it could rest on or interfere that I could think of is air con and alternator.

[muzzrx]

Sorry to Hijack - But what OBD2 Adapter do you use ? I'm finding it hard (yes after seaching) to find a confirmed working adapter for a 2004 GT. Thanks and I hope you solve your problem, I'm getting one for an idling issue.

[Jim2013]

Sorry to Hijack - But what OBD2 Adapter do you use ? I'm finding it hard (yes after seaching) to find a confirmed working adapter for a 2004 GT. Thanks and I hope you solve your problem, I'm getting one for an idling issue.

Not sure TBH as the mechanic is the one reading the codes for me. Looks like an old lap top in an industrial case! Hardcore workshop equipment...
I think there's a whole section devoted to what you are asking...looks like you may have searched already.

Jim.

[Jim2013]

Car still not well - has been with mechanic for 2 weeks whilst I've been on holiday.
To his credit he's been working on it for free (labour wise) up to now but he can go no further with it.
Still throwing same code and is basically un-drivable. P0122 is the reoccurring issue.
So far:
• New battery.
• New O2 sensor.
• Second hand Throttle Body Assembly.
• Second hand Pedal Sensor.
• Throttle relays were swapped.
• Traced harness back to ECU for loose connection.
Still cannot find the root cause and have a box of parts I dont need.
Looks like a trip to an auto electrician to physically check voltages..
Saying that I do have a multimeter and the Subaru workshop manual....