Loutorious

Hi

Hopefully someone can shed some light on a no start problem with my 2005 Cayenne TT.

I was on my way home and drove about 10 miles after the low gas light turned on. Normally I may risk driving 25 – 30 miles without worry after low gas light. This time the car died. I was able to coast to a safe spot and evaluation my situation. Tried to restart without success, the starter did not even turn. Illogically hoping it was just out of gas I called a friend. But after about 5 minutes I tried to start again and it started. I did notice it took slightly longer to start, maybe 1 second more than the usual instant start. Immediately racing to nearest gas station but car died again after about 1 mile. Waited another 5 minutes, started, drove another 1 miles or so. This time I waited for the 2 gallons of gas from friend. The additional gas didn’t seem to help but stalling 1 more time I eventually I made it to the gas station. Filled up and car ran fine again, perplexing but wasn’t going to complain. Drove home, let car idle for 30 minutes, all seemed good. Thought about faulty fuel pumps and stuffs.

Next morning car started right up drove 20 miles. Afternoon drove 4 miles, car died. This time the car could not start up again after 5 minutes, just cranks for about 2-3 seconds then total shut down, will not allow starter to turn. Waiting another 5 – 10 minutes car will allow starter to initiate for the 2-3 seconds but no start. Towed car home and thought the problem must be fuel pumps since gas tank was full.

Following days I changed both fuel pumps, fuel filter, and fuel pressure regulator hoping to avoid future problems since car already has 165,000 miles. No dice, exact same symptom, starter cranks no start then shut down, wait a few minutes will allow starter to crank again but will not start. Suspecting cause of no start unrelated or in additional to fuel pumps issue.

Checked fuel pumps with external 12v battery both work. Checked fuses and both relays, seems good but changed anyway. Checked again all fuel hoses not cracked or pinched, and connected correctly. The limit of my ability to locate the problem reached.

It didn’t feel like there was a catastrophic failure such as a blown engine. When car stalled it just lost power, no weird noise, nothing dramatic. I can hear the fuel pump priming for a second when driver door opens. Have not check fuel line pressure in engine compartment, should I check? Battery on trickle charger now voltage 13.1. I’m just a part changer clueless with electrical stuffs. No idea how to check control modules. Someone please help, or direct me to a good shop near Huntersville NC. Thank you, Lou.

Some more info that may be useful:

2005 Cayenne TT 165,000 miles
New battery March 2016
T hose back of intake January 2016 $2600 Ouch, stupid 50 dollar hose
Had to change T hose at a shop because I was 600 miles away from home
Oxygen sensors July 2014

- Changed these when car had rough start after gas fill up – February 2014
Venturi tube 94811007003
Vent Line Tank Ventilation 94811020201
Vent Line 94810721753

Change oil every 5000 – 8000 miles mobil 1
Spark plugs 120,000 miles
Coils 85,000 miles – still good no crack
Aluminum coolant hose 85,000 miles
Starter 85,000 miles

Here are fault codes from Durametric:

Bosch Digital Motor Electronics 7.1.1

P0685
ECM/PCM Power Relay Control Circuit - No signal/communication, test conditions are not-completed, fault is not currently active and is not causing a DTC light

P1549
Vehicle electrical system voltage via main relay - No signal/communication, test conditions are not-completed, fault is not currently active and is not causing a DTC light

P1550
- Implausible signal, test conditions are not-completed, fault is currently active and is not causing a DTC light

P0198
- Upper limit value exceeded, test conditions are not-completed, fault is currently active and is not causing a DTC light

Tiptronic Transmission

1314
DME control module - No signal/communication, test conditions are not-completed, fault is currently active and causing a DTC light

Instrument Cluster for Cayenne

771
Fuel level sensor 1 - Open circuit/short circuit to B+, test conditions are not-completed, fault is not currently active and is not causing a DTC light

438
Fuel level sensor 2 - Open circuit/short circuit to B+, test conditions are not-completed, fault is not currently active and is not causing a DTC light

562
Oil level sensor - Implausible signal, test conditions are not-completed, fault is not currently active and is not causing a DTC light

1314
DME control module - No signal/communication, test conditions are not-completed, fault is not currently active and is not causing a DTC light

Gateway

1314
DME control module

nodoors

Sounds to me like you do not have a fuel issue, but an electrical issue.

Is it currently in a state where it will not start?
What voltage reading are you getting on your OBD/durametric scanner from the computer?

Have you tried providing power at the jump start connections under the hood to see if that clears the problem?

It could be as simple as the battery ground to chassis. I would definitely check that next.

nodoors

With that said... are you hearing the drivers side fuel pump prime when you open the driver's door?

When the engine will turn over, does the starter motor sound like has the same fervor as usual?

A fuel pressure gauge and OBD scanner (with Torque App) will go a long way in solving this mystery. Those two tools are certainly worth the cumulative $45.

deilenberger

What does the voltmeter on the dash say? I'd guess that the battery has gone to charge heaven given the number of codes you've pulled up. Or the alternator. Or both.

@nodoors - the fuel pressure gauge is handy - Harbor Freight has a dandy one for around $35.. but since he's replaced all the fuel related stuff already (shotgunning it basically) - I'm not certain it will help. He has a Durametric (he got the codes using it) which blows any OBD scanner right out of the water for diagnostics.

@loutorius - a real clue on modern cars that there is a battery/charging system problem is when you see improbable codes appearing from all over the vehicle. The modules do that in low voltage conditions. The second code you listed "P1549 Vehicle electrical system voltage via main relay - No signal/communication" really points to this possibility.

Since yours is a 2005 model it's entirely possible you have two batteries. I see you replaced one in March of 2016, have you found/tested/replaced the other one? One is in the normal spot under the drivers seat. If you have a second one it will be located under the spare tire in the spare-tire well in the rear of the tail section. The system should switch over to the good battery if one fails, but it may not, or the one has failed so badly that it's putting a large drain on the system keeping the other one from fully charging.

So - first step - find out how many batteries you have. We know there is one under the driver's seat. I'm guessing that's the one you changed. It's primary use is to start the vehicle. If you have a second one under the spare tire - it needs to be removed and tested. Chances are if one went bad - the other one has now followed it.

I doubt it's a fuel related problem since you've replaced all the usual suspects.. but if there is a Harbor Freight around you, might be worth picking up their kit and checking the pressure at the fuel rail. There is a Shraeder valve on the rail that is there for that very purpose - makes it very easy to do once you have the correct gauge.

Loutorious

Thanks for the input.

I have only 1 battery under driver seat, Sub woofer under spare tire. Voltage is 13.1, have a battery trickle charger on continuously, battery is new anyway.

When I try to start car, starter will crank for a few seconds, strong, but just can not start.

I do hear the driver side fuel pump turn on for a second when driver side door is open.

I guess will try to get a gauge and check fuel pressure and see what happens. Someone suggested maybe check crankshaft position sensor / circuit, may cause similar problem.

Will update even if I have to tow to dealer. Thanks

Loutorious

An update to the no start problem. It was an electrical relay in the ignition system. Mechanic told me it is relatively rare for this to happen. At least now I don't have to worry about fuel pump problems. Hope this will help the next guy.

Corvetteboy6988

I haven't been hearing the fiel pump prime when I open my drivers door, im getting a 1314 dme code.
some wierd drivability problems, surging, lack of power, jerky power delivery, rough downshifting to 4 and 3. Some drives its worse than other times.
any thoughts?

BobcatBrian

Do your driver's door puddle lamp and the dome lights turn on when you open your driver's door? If not, you probably have a dirty or defective microswitch in your door actuator. That would help with cold start up, but probably not the other drivability issues. What year and model?

Corvetteboy6988

Yes, dome lights and puddle lamp under the door turn on.
Im not having any starting issues, so yeah, wouldnt think it would affect my driveability issues either, but was wonder if it was somehow related to a pump going bad, etc.
I think there is a test to run on the priming of the pumps in my foxwell scanner, Ill try that and see if it works.
I see a lot on this 1314 code and it seems to related to a lot of varying things, so was trying to make a connection since I havent heard the pump prime when opening the door in a while. (unless its temp dependent, its summer time time and plenty warm).

BobcatBrian

I would think the pump not priming is a wiring, relay, or control unit/module issue more than a problem with the pump. But if you're on the original pumps, they do seem to have a moderately high failure rate that they get mentioned on forums and facebook groups. My carpet is cut so I assume they were done at some point or maybe that was for the recall?

Do you have drivability issues with PSM off or in sport mode if you're a 957?

Corvetteboy6988

Not a 957, 955TT.

I am getting the pump to prime opening the drivers door now, either the criteria wasnt met, or the new battery I just got made the difference. Was seeing 12.1-12.2 volts even aftercharging.
Still having some drivability issues, surging, jerkiness, but its a lot better (the idle, othroughtness) with the new battery.