Hi,
This is my first post... I'm a 59 yr. old female that has managed a few minor repairs on my 2011 970. First repair was a horn, 2nd was the driver's side window control unit. I am basically tired of driving/towing my Panamera 1 hour to my nearest Porsche dealership for repairs. Its expensive, time consuming... and I have not always been satisfied with their work. When I got a warning, "Reduce Engine Power" and a Check Engine light I decided to buy a code reader and investigate the problem with the aspiration of repairing the problem. Hahaha! So I got a bunch of faults codes, most have something to do with the HPFP others do not. My question to anyone who might read this and be familiar with reading codes and diagnostics, Is there a way to determine if the failure is the fuel pump sensor or the entire HPFP? The problem occurred when driving. When I start the car it takes about 3 seconds to turnover and start and runs rough for about 15sec. before settling down. I have attached the list of errors. Thanks to anyone who is willing to guide me on this problem. By the way, I've been watching a bunch of videos on how to replace the HPFP. I'm ready for that

Transmission Control system 01
C418 DTC-Check PSM control unit fault memory content

PSM Control System 01
C12019 DTC-Check PSM control unit fault memory content

Driver’s Door Control System 01
0398 DTC-Door mirror heating, electrical fault

Level Control/PASM Control System 01
000220 DTC-Vent solenoid valve, ON time exceeded

Parking brake Control system 02
000026 DTC-Emergency braking not available
000021 DTC-Drive away release, not available

Front-end electronics control system 02
C11007 Refer to manual
881202 DTC-Key battery flat

DME control system 05
P1021 DTC - Fuel Pressure quantity
P12A1 DTC-Fuel high-pressure sensor implausible
P1023 DTC-Fuel pressure/quantity too low at start
P1026 DTC-Fuel high pressure implausible
P1031 DTC-Fuel high pressure sensor stuck at start

 

The first thing I would check is the battery, 970s are very sensitive to battery voltages and cause the software to throw all kinds of codes. How do I know, because my 970's first issue involved a faulty battery which was replaced and within a year began spontaneously generating codes again! This time I replaced the battery myself and purchased a CTEK maintainer to plug in when the car didn't see much use. I haven't had the problem since !

 

I'm a 991 owner, but this tends to be an issue across the models. Multiple seemingly unrelated errors are often just due to an aging battery. The car still starts fine, but the voltage isn't within exact parameters so it starts doing really, really screwy things to our cars since everything has a sensor.

Check the negative post of your battery. The top of the actual battery post will have four numbers, e.g.: 22/11. Top two are the week and bottom two are the year of manufacture. If your battery is 4+ years old that's likely the issue.

Could be you just need to install a new battery.

 

I'll give that a try. It sure would make it a simple fix. Thank you for the response.

 

I have a CTEK and have not been using it. The car is my everyday drive but it hasn't been driven much since the pandemic. I will check the battery tomorrow. Thank you for the response.

 

I brought my car into a local alternator shop and they tested out the battery. The guy there said it looked good. The battery is just over 4 years old. Because the battery is still good, regardless of its age, do I need to look for another cause of this problem and all the error codes? I'm grateful for any suggestions.

 

It still could be the battery, like I said the system is really finicky about voltage and although the battery might have been in acceptable range, if it was on the low end it could have dipped below when the codes popped up. Have the codes cleared since they first appeared? If so, I'd just press on and not worry about it. It could be your battery was slightly low when they popped up since you hadn't been driving the car much, but after a drive to the shop the alternator charged the battery enough.

If the codes are still there, and I was attempting the repair myself (I do all the work on my car myself now that it's out of warranty), I'd still replace the battery as a first step and reset the codes with a scan tool before diving deep into things like replacing the fuel pump. An AGM battery will run you around $200 at places like Sam's Club or Costco. Doesn't have to be the Porsche branded battery. I just put a Duracell in my car a few months ago (it had the original battery that was almost 7 years old). "Worst case" scenario is that doesn't fix the issue and you've replaced the battery a couple years earlier than it needed to be replaced.

 

You could always install a battery monitor like this.

Gives you peace of mind that the battery isn’t failing. Or confirms if it is.

 

I have a 17 so the battery is about 5/6 years old at this point. I'm having some similar issues as above, is there a way to check if the battery is the culprit before replacing, or should I just swap it out?

 

If it is original, you should consider replacing it for sure. If nothing else it will help prevent more issues for you in the future.

 

I would clear the codes then reread after the fault reappears. Someone on here may be able to help with that. There could be a bunch of stuff unrelated to the current problem. (If your battery tested ok, I wouldn’t replace it.