Hi Everyone,

New here! I have an 03 G35 Coupe / 5 AT / 120,*** miles

My problems first started shortly after replacing my t-stat & radiator (had a leak in the rad)

After doing the above work with a couple buddy's I went to start up the car, and she died immediately (left MAF unplugged) Plugged it back in and was good to go with the exception of a CEL.(as expected)

Went to O'Reily's and got the codes ran just to see what they'd be.. At this time I had NO performance or MPG problems.. Got home & cleared the light successfully using the pedal reset procedure. Codes below (listing these codes because a couple stayed with me as youll see later)

C1130
P0550
P0102
P0327
P0113

After the pedal reset I was good as far as full performance, but never checked again for codes, as everything was operating properly.. Then..

I left to work one morning.. started fine, and drives fine until you give it gas.. I tried passing a rusted Civic EX driven by a smiley douchie looking 16 y/o.. I was in 3rd gear (sport mode) & I had absolutely NO pull.. Feels like half of the usual performance... (i know these arent the best on low end torque but this was HORRIBLE). was as if I was in 4th or 5th gear.. I then downshifted to second, where i experience a lag in which I normally do not encounter.. Upon downshifting, power still feels decreased by at least 10-15%... Didn't pass him. I looked.... Retarded. Fast looking, fast sounding, but couldn't pass this asshat. Keep in mind I have NO CEL..

The car has NO low end torque. If I floor it at a dead stop, tire spin is out of the question Any rpms under 4.5k are extremely slow and lacking of power for any gear. Once i hit 4.5+ its as if im in a sh*tty honda again, and Vtec kicks in

Idle seems unsteady. sometimes stays at 650, sometimes it steadily flucuates betwen 450 - 550 rpm

Anyways... Decided i should go get the car run for a ghost code... Sure as Sh*t..

P0327
P0550

So.. I wrongly assumed the PSP sensor couldn't throw me in limp mode, and decided to attack the most logical thing causing the immediate issue. P0327 -- knock sensor short or open circuit..

From my research; 8/10 people who have gotten this code ended up having a faulty harness vs the sensor itself being bad.. So.. I ordered one from Z1 & put it in myself.. Upon inspecting I see the old knock sensor looked fine.. Was confident it was the harness then..

I start it back up after getting it back together (easy job BTW) & bogging/bad MPG was still present.. Still no CEL..

Went to Autozone, and ended up with..

P0550 -- this f*ckin guy...
P0328 -- Knock sensor high input

So... I did what I thought seemed the most probable culprit next.. Knock sensor... $40 one from Autozone.

Got it in, and I am STILL have the same issues, and the same code! & i STILL DONT HAVE A CEL ! From my research I am the only person where one or the other DIDNT fix the bogging down/clear the code(s)...

My current thoughts are... OEM sensor (praying to GOD)

Should I start looking into the P0550? (PSP sensor) or get an OEM sensor in first? I don't see anyone else with this exact combo of codes.

From my research, I have seen others use cheap $15 sensors off ebay without immediate issue.. Only negative i have seen using aftermarket is they would die prematurely or almost immediately after driving BUT it still fixed their problem PRIOR to failing... I have even seen other threads where people used the same AEM Autozone sensor i got, without it dying prematurely at all..

At a complete loss of ideas outside of having a DOA sensor, or a truly bad PSP sensor.

I cant help but lean towards the PSP sensor as I overheated several times before I replaced my radiator & t stat. (never hit H) (coolant was barfing out of radiator and possibly leaking onto PSP sensor & pretty much all over the bay on 2 occassions)

I have also checked the throttle body for build up(was surprisingly clean)

I have performed ECU rests everytime i went back in for the sensor..

Oil is fine, replaced injector o rings, cleaned MAF sensor & wire connector with CRC.

Cleaned air filter, re oiled (K&N)

Mods include:
Transgo Shift kit upgrade
HKS Hi-Power cat back
Z tube intake (from Z tube)

What could this be?!?!?!

ANY help or recommendations will be highly appreciated.. I love this car more than my pregnant GF. (JK) (or am I) I plan on keeping it (talking about the G) (bad joke I know i know haha) and eventually with time and money building it into a beast!!! I have spent ALOT of time & money with this car so far, and it kills me knowing shes sick!!!



Thanks!!

Come on guys... 50 views but not a single response or welcome! Where's my G's at?!

Seriously though.. I have seen countless posts on here, 6MT, Nico, and my situation has definitely never been published. Z Nationals is coming up, and I NEED my baby fixed by then!!

Help me help my baby!

Thanks for the great support, guys. Outstanding.

Come on guys. Imagine your g running at only 60-70% power

is there really no one with any input?

https://g35driver.com/forums/g-spot/...ml#post7112185


Sorry, I didn't realize that you had a reading comprehension problem?

I provided you the link to the EC chapter (Electronic Control).

I guess you are too lazy to read and search?

See page EC- 396

DTC P0550 PSP SENSOR
PFP:49763
Component Description
ABS003FF
Power steering pressure (PSP) sensor is installed to the power
steering high-pressure tube and detects a power steering load. This
sensor is a potentiometer which transforms the power steering load
into output voltage, and emits the voltage signal to the ECM. The
ECM controls the electric throttle control actuator and adjusts the
throttle valve opening angle to increase the engine speed and
adjusts the idle speed for the increased load.

Do you know how to use a multi-meter and read electrical schematic diagrams?

If not perhaps you should have a pro do the troubleshooting for you.

FWIW using non OEM replacement parts may only complicate troubleshooting.

Telcoman

I can't say I'm a master mechanic or entirely inclined on electronics such as sensors, wiring, ecu, etc.

I do know how to read though, and as a being with just enough common sense to perform low level troubleshooting, i have read that section of the FSM prior to posting in here... The thing is, i don't know to to test anything on the electrical at all. Also, it seems that the PSP sensor can indeed limp mode us, but I'm receiving conflicting information. Some say only on turns, some say entirely, some say not at all..

To be fair, I didnt see any specific chapter you pointed out either, i thought you just threw the entire EC section at me lol..

I guess the right question now is; would it be silly to think my limp mode is being caused by this? Would it be dumb to replace this sensor, as well as putting an OEM KS in? Or should i just bring it to a mechanic that can troubleshoot the electrical/sensors?

Anddddd... What is FWIW? Lol

Even though i find most of the community on here non existent, or douche baggy & unhelpful 6 times out of 10; i thought i would take the time to update just in case someone else happens to run into the clusterf*** of a problem.

so the PO328 code was legit. Was not the knock sensor (changed it out 2 times) or the harness integrity, but the harness clip that connects to another harness under the car was not plugged in all the way... Started it up, ran for the codes & all that remains is the P0550. Performance is back 100% and runs strong as ever


As for the P0550; someway, somehow, the power steering pressure sensor is literally broken off of the pressure line. Broken all the way through somehow. Lucky because the way it broke prevented discharge of fluid, preserved my PS, and doesn't seem to have any effect on the car other then the code.

New one is here, and plan to throw it in today.

Glad you got it fixed, after a re-read of the entire post/replies I don't get the "douchey" vibe at all 😃 the troubleshooting steps are in the FSM, you were given the link, I don't see the problem.

To answer your other question, FWIW = for what it's worth.

GLHF!