dbspcl

In the ongoing saga with my car going into fail mode (the wrench light) and sometimes throwing a MIL (engine light, mostly code 2135 and rarely 0446 as well), I've made some progress but am still stumped and looking for help. This happens at various speeds across the board so there is no correlation there. When it goes into safe mode, turning it off and right back on works when the starter is fired (sometimes coasting and popping the clutch to get it back), runs fine for a little while, then does it again.

2135 is a drive-by-wire code, so I tried swapping out the TPS (throttle position sensor). No difference, still did the same thing.

So I went ahead and got a new FRPP throttle body assembly, comes complete with TPS and TAC. Hooked it all up, same problem.

I've been logging PID's and will continue to see if I can detect what is happening - at this point I'm down to just the pedal in terms of drive-by-wire components. When I check the TPS PID's, I get a smooth range throughout and a proper positive-negative correlation between TP1 and TP2. The pedal APP1 and APP2 PID's look fine as well.

The code 2135 states "Throttle/Pedal Position Sensor/Switch 'A'/'B' Voltage Correlation". At first, I thought this referred to the correlation between the TPS readings, TP1 and TP2, but clearly with a new TPS this couldn't be the case (bad TPS). I'm thinking now this is referring to the relationship between the pedal position (APP1) and the TPS (TP1/TP2), which I think would point to a bad pedal.

I wonder if it is possible that the MAF itself is also a possible culprit? I know that if I leave the MAF connector off it will immediately trigger a safe mode and a wrench icon. The confusing thing with that is that MAF is not part of drive-by-wire and I thought the wrench ALWAYS indicated a drive-by-wire problem...

Any ideas would be welcome.

Nuke

A concise list of your mods would be good for starters.

dbspcl

2007 GT, 5-speed, JLT CAI, Brenspeed 87 tune, PA Performance 130amp alternator. I have also bypassed stock starter and fan wiring/relays.

In doing some more data logging, I am looking at the TANK_PRESS PID (since I sometimes also get a 0446 code for EVAP control), and I am seeing it go negative slowly until it hits -7.5 or so (not sure what the units are) and that moment seems to correspond with when the car goes into safe mode. I've seen it on two different test runs now. Anyone know what the expected values are for this PID? I've attached a PNG of the graph.

JCON

My car shut off and fail safed about a dozen times over two months two years ago with the following random assortment of codes:

P0446*
P061B*
P151A*
P2106*
P201
P202
P203
P204
P205
P206
P207
P208

*threw these codes every time

Issue ended up being a bad aftermarket panel filter. Check your cone filter for any warping or areas where debris/particles may be able to enter the MAF area.

dbspcl

Looks like my problem is related to the TANK_PRESS PID - I have several runs now where tank pressure (I'm assuming TANK_PRESS is referring to gas tank pressure) starts dropping and gets to -7.5 or so, triggering the shutdown. That must be a safety threshold - there is not much info online about this and nothing in the workshop manuals.

If I understand correctly, the gas cap is fully sealed (not vented), and the fuel pump is pulling fuel out of the tank, so there must be some way that fuel is replaced with air. I know that the EVAP system takes vapors that collect in the tank and purges them to the manifold, but is that the same system that also allows air to flow into the tank to replace the pumped fuel? Is that using the vent solenoid on the canister or is it some other vent on the tank itself?

Any help is appreciated. In my datalogging, I see the PURGE_FLOW PID go from 0 to 1, and then PRG_FLW_REQ starts to increase (but the numbers are still very low, PRG_FLW_REQ only gets up to 0.12 or so). I've attached a couple more pics from different runs.

There is also a PID called TA_ERROR - does anyone know what that indicates?

Derf00

So it sounds like fuel delivery problem.

When you shut down and start back up, how does the fuel pump sound? If it sounds noisey then quiets down, you are getting air in your fuel line (cavitation).

Perhaps have a shop do a tank pressure test so you can rule out the tank and evap system, then look at your fuel system (pump and lines).

dbspcl

Derf, it's interesting you mention noise based on cavitation - I have had an issue for several months now where I'll turn key to ON position and then get a loud whirring, sounds like an actuator of some sort, it slowly gets softer until it is gone after a minute or two. I have had problems with the vent door actuators and actually have had a couple of them out of the car for a while, and I've assumed that the whining I hear has something to do with that as I think the vent panels cycle when the key is turned on. I had thought about it being the fuel pump, but the sound is coming from the dash or some other location forward of the seats as far as I can tell, so I assumed it was not the tank-mounted pump. I will try to find exactly where the noise is coming from.

As to the tank pressure test etc. that would be checking for leaks correct? But I am getting negative pressure building up, which seems to be a problem with air going into the tank. Problem I have is I don't know where that air is supposed to come from, back through EVAP system/canister, or through some other vent.