2010 ST-X Limp Home - EGT error codes

[Navmanstx]

Hey Guys,

I just bought a STX and am having a issue with the car losing power. Happens about 5-10km into a drive. Car feels like it's going into limp mode with barely any power and struggling to get over 3k. No engine light appears. If it turn the ignition off and back on and it performs fine for a while.

I have replaced the boost control solenoid. Issue remains
Replaced battery and cleaned terminals - issue remains
Took it to the mechanic that saw the Exhaust Gas Temperature (EGT) codes being thrown when it happens. Replaced the affected sensor (closest to the turbo). The issue remains

Where should the next bit of investigation be? I have read about a million things over the past couple of days relating to this problem from dodgy fuel injectors, pressure release valves, EGR blocked or dirty, ECU water damage and the list goes on.

Just after a bit of guidance from you guys, I don't know anything about these cars and I just want it fixed so I can enjoy my new ride ��

Cheers

 

[bods]

Hey mate,

Sucks a bit, but hopefully you will get there. Try loosening the fuel cap a bit and take it for a drive, suction control valve issues are reasonably common on these motors and from memory loosening the fuel cap can help if this is the issue.

I'm sure someone else will be along to help further, but that is a start... good luck.

 

[Old.Tony]

+1 for the SCV being the most common cause of these symptoms.

The best test (without analysis equipment) is observation under initial load. Start the car, drive gently/moderately until warm. Then, from a standing start, accelerate at 50% throttle or higher.

If the car had been performing normally beforehand, chances are your turbocharger is operating normally, which means both the turbocharger is in good condition and the control mechanisms (BCS and vac lines). This would indicate a faulty or dirty SCV. Try a can of good injector cleaner (Liqui Moly Fuel System Treatment is one I've used before with success).

If the car had NOT been performing normally, you could check that the vac hoses are all tightly attached (if they can be easily turned on the barbed connectors, there's a good chance that they've hardened and are leaking) and if that's all good, inspect the turbo itself.

Remove the air hose from the intake of the turbocharger and try and turn the turbocharger impeller. Wiggle the shaft with the tip of your finger. You shouldn't get a lot of play in the shaft and it should rotate smoothly. It will be a little reluctant to turn when cold with no oil flow in the bearings, this is normal.

The last control fault may be from the brake booster. We've had a couple of reports of the booster being faulty, causing a loss of vacuum in the system and this causes the turbocharger to not function as expected.

However, given the description you've given so far, the SCV is at the top of my suspect list. Try some cleaner and see if that improves things - if it does, but the problem hasn't gone away, replacing the SCV would be the next step.

 

[Czechmate]

Not sure if this is any help, but ill put it out there

I got limp mode in my 07 STX a few years back

I pulled over and scanned for fault codes on the spot with the Torque app and OBD dongle

It came up "suction control valve jammed" straight away, clear as clear

So if it is the SCV, you can get an obd bluetooth dongle and the torque app for less than $20 and have a look

Or if you wanna spend more money and get it quick, go to Supercheap and buy the bosch OBD and ABS scanner, it works good on D40s

 

[Navmanstx]

An update,

I had the car taken to Nissan and they noticed that there was a software update missing in the ECU. They reset the ECU and applied this update.

The car has been perfectly fine for 4 days, roughly 300kms of driving No issue, performing well. I tested it out on a 50km drive and it was fine.

Took it on a trip today. 80kms into it, same issue. Stopped car and started again the issue returned in 20kms. Stopped car for 10 mins while I ate, drove another 110kms and it did not fault.

Any ideas? This thing was constantly faulting before at the dealership. They did something right for me because the car was running perfect for days. Now it's back..

 

[Old.Tony]

If it's the SCV you'll be able to trigger the fault deliberately. Try these two methods:

1) Drive the car gently - no more than 1/3 throttle. Smooth, slow take-offs. No major hills. Just take it easy.

2) Give it some berries. Use the ponies. Whatever, use 3/4 or more throttle.

If 1) gives you no grief and 2) instantly causes the fault, check that you're not overboosting and if boost levels are ok, replace the SCV.

If it still happens in 1) it could be an air leak into the fuel system (not too likely) or a faulty connection on one of the sensors (boost pressure, fuel rail pressure, MAFS). It could be a dirty MAFS for that matter.

If 2) doesn't cause it, there's nothing wrong with fuel flow and you're again back to looking at sensors.

Overboost is monitored by watching the boost pressure (intake manifold pressure) and shouldn't read "vacuum" which indicates that the ECU has detected too much boost. Mine does this now and again lately because I've adjusted my Tilix valve a little too far the wrong way and need to fix it.

 

[Navmanstx]

Thanks Tony,

I will test that sometime today.
I now am facing an issue with the idle.
When I started the car today I could feel a heavy vibration at idle, not too bad but it shook the car. Drove it to work, and noticed the vibration happens when the revs drop and just before the car gets to it's idle RPM there is that same vibration.. every time, you can rev the car and just before it gets to idle the vibration will appear..
One thing after another with this car...

 

[Navmanstx]

I got a ODBC scanner. It threw a P102b as a confirmed code and a P1028 as a pending code.

P102b is the EGT sensor but the P1028 is the Exhaust Gas pressure sensor..

Funny thing is, I have noticed when it triggers (after the dealership fixed it).. only when cruising on the highway... It's like it doesn't like gentle throttle..