CPTPanamera

Hi All.

I was about to drive my 2017 Porsche Panamera 4 E-hybrid this morning after a 2 week holiday and now it won't start. Everything lights up and looks normal, but when I select to go from electric to the engine, it just won't start. No alarm, no signs of failure?!

I do have a faulty fuel cover which won't lock, so I wonder if the fuel might have been contaminated? Any ideas as to what this can be?

sac02

If fuel was contaminated it would TRY to start, so I don't think that's it.

There are others here with more in depth knowledge of the Porsche hybrid system, but in general it is similar to other vehicle hybrids, and I am familiar with those so I'll toss out a couple things I would look at.

1) what is the voltage of your 12v battery?
2) can you put your 12v battery on a charger overnight and try again in the morning? These cars are really sensitive to battery voltage and do weird things when batteries are getting weak.
3) if SOC of hybrid battery is too low, vehicle may refuse to start - but usually this is accompanied by a DTC and you did not mention any codes or warnings.

If I had to take a stab in the dark, a 12v battery that is flat enough to not start the car, but has enough juice to turn on the interior lights and radio (so everything "looks OK") is my guess.

CPTPanamera

thanks for the reply! It’s sitting with 15 volts as soon as I turn on the ignition. No funny lights, no flickering and no error messages. Nothing happens what so ever. I have attached a picture. Plenty of juice for everything else like airsuspension, lights, A/C etc. Very strange!

I

chaos2984

Your range looks to be an issue. You should be able to plug it in correct? If so plug it in to charge then try. It looks like its functioning correctly. Will it let you drive it on E power?

CPTPanamera

range is down to zero now, but I had 2 miles when I tried to turn it on initially. Unfortunately I’m out or range for a charge at this point. No driving on E-power unfortunately. Not even when I had the 2 miles available.

sac02

OK so my theory that it is a flat 12v battery is maybe not it? But I still think you should thoroughly test it / eliminate as a possible cause - MANY weird issues on this board from weak 12v batteries.

Does the Porsche hybrid system have a traditional 12v starter, or not?

Some hybrids ditch the 12v starter for weight / cost / complexity savings. These systems use the HV battery and traction motor (electric motive motor) to start the engine.

Some hybrids keep the 12v starter. Usually the engine is started as above, but the 12v starter is kept as backup for 1) really cold weather (like sub-zero F), and 2) if the HV battery SOC is low you can still start the car with the 12v battery / jump box.

Is it possible that the Porsche system is the latter, and since your HV SOC is low, it can't/won't try to turn over the engine? And with low SOC, it also won't move in EV mode.

HV = high voltage
SOC = state of charge
EV = electric vehicle

chaos2984

If the car is at your house just get an extension cord and use the 110v plug in and charge the car. I think your out of power to start the engine. I don't think there is a true hybrid option for the 971 panamera. I think they are all Plug in hybrids. I think the only true hybrid was in the 970 with the 3.0T engine. As SAC said if your Ev battery is to low it won't be able to start the engine. I don't think the 971's have starters on the engine. They use the EV power.

Andy Liu

nope you are wrong. I think his 12v battery is bad. that is what the 12v is for. The hybird battery can power the car still and it won't run until it is empty anyway. there is a reserve. So the OP needs to check if his 12v battery is bad. That is why the 12v is there just incase the battery is too low or don't have enough to start the engine. Pretty much the hybird is everything the regular car is.

Thebig1

I know 2020 cars dont have a starter motor, the hybrid motor on the transmission starts the IC engine so its the hybrid battery that does it. Some power is kept in reserve for starting and not for driving etc.

chaos2984

I don't think there is an issue with the 12v battery. If there was an issue with the 12v battery then it wouldn't even be able to close the contactors in the HV pack. Also if you look at his picture the HV system is functioning and charging the 12v battery system. If it was an issue with the 12v side the engine should start as the voltage on the 12v side is in acceptable range with the EV system fully powered up.

You can force start the engine anytime you want in these cars. The Sport Plus mode should automatically force start the engine. It did in the V8 Turbo model that I drove.

orca15

I'd still (despite the good thinking above) charge both batteries. And then switch to sport mode to see if it starts. I've seen so many weird reports of malfunctions when the 12V is low, and 15V on the meter means it is really trying to charge the 12V - if the 12V was full, that would drop significantly.