PCM Malfunction - Help!!!
05-26-2021, 03:44 PM
#16
RL Community Team
Rennlist Member
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05-27-2021, 09:14 AM
#18
I believe there must be something wrong with a "module" Maybe the PCM (am trying to research what that is and what it "stores"). The person before me replaced the "Radio" (he called it that) and had it programmed at the dealer. Dealer notes..."Customer states amplifier was recently replaced-program new amp to allow operation" The guy said it only played out of one speaker, that's why he took it to be programed...then the dealer notes: Multiple faults in system-allowed amp to operate by disabling protection mode." OK so was it IN "protection mode" (maybe didn't recognize the car it was in) OR did the tech disable "protection mode" so it would operate? I'm thinking it was in protection mode and he corrected it. Either way was that "amp" he called really the PCM?
He also replaced "CTRL UNIT 958907279A interchanges with #7PP90279CF" (that translates into some Rear Body Module) ? Anyway another reciept shows "Customer request PCM programming... and it was done..he didn't say if that was the "amp" he installed but the "PCM" was programmed on a different day and a month before the "amp".
Here is what is NOT working....NO USB power, NO LED's on door panel, No Satellite ant (according to XM display) SOMETIMES it resets door lock, light, reverse mirror settings. Temperature setting ALWAYS start at 84. So I'm trying to narrow it down to what "unit" is in common with all those functions. I can't find "PCM" as any 1 module...Blue tooth works, the display works and remember when I change things. MOST of those issues are tied to the PCM (USB buss, Sat Ant) but would it store your comfort settings?
Thanks for reading and thinking about this.
He also replaced "CTRL UNIT 958907279A interchanges with #7PP90279CF" (that translates into some Rear Body Module) ? Anyway another reciept shows "Customer request PCM programming... and it was done..he didn't say if that was the "amp" he installed but the "PCM" was programmed on a different day and a month before the "amp".
Here is what is NOT working....NO USB power, NO LED's on door panel, No Satellite ant (according to XM display) SOMETIMES it resets door lock, light, reverse mirror settings. Temperature setting ALWAYS start at 84. So I'm trying to narrow it down to what "unit" is in common with all those functions. I can't find "PCM" as any 1 module...Blue tooth works, the display works and remember when I change things. MOST of those issues are tied to the PCM (USB buss, Sat Ant) but would it store your comfort settings?
Thanks for reading and thinking about this.
05-27-2021, 09:22 AM
#19
Intermediate
I have thought about this set of issues and can't think of any way to relate them together. However, one thing that maybe you could rule out is the battery. You are out of warranty, right? So there's a chance you are on your original? If that's the case, it would be an idea to replace it (<$250 DIY). IME It is not uncommon for very weird / intermittent electrical gremlins to surface when a battery is on its way out. Something about all the parasitic draws as well as the loads put on the the battery by these cars. If you have any doubts at all about the battery, it would be a good place to start and give you a foundation to address the problems. Sorry but I can't come up with anything else.
Thanks for this input...I will check the battery...the guy before me told me he had to "jump" it if he let it set 4-5 days...I haven't had that problem but I did drive it 400+ miles home the day I bought it.
It's sat (at most) 2 days since then. I wonder if the battery has to be "programmed" into the car like my BMW? My boss swapped his battery out of his Z4 and the 3rd brake light didn't work, the A/C compressor wouldn't turn on and a few other odd things happened but he had it "programmed" by the dealer and vola...everything worked again!
Taking it to the shop tonight for an overheating issue (pump and thermostat were replaced in March)...maybe air is still in the system...I'll have them check the battery then.
05-27-2021, 01:44 PM
#20
Thanks for this input...I will check the battery...the guy before me told me he had to "jump" it if he let it set 4-5 days...I haven't had that problem but I did drive it 400+ miles home the day I bought it.
It's sat (at most) 2 days since then. I wonder if the battery has to be "programmed" into the car like my BMW? My boss swapped his battery out of his Z4 and the 3rd brake light didn't work, the A/C compressor wouldn't turn on and a few other odd things happened but he had it "programmed" by the dealer and vola...everything worked again!
Taking it to the shop tonight for an overheating issue (pump and thermostat were replaced in March)...maybe air is still in the system...I'll have them check the battery then.
It's sat (at most) 2 days since then. I wonder if the battery has to be "programmed" into the car like my BMW? My boss swapped his battery out of his Z4 and the 3rd brake light didn't work, the A/C compressor wouldn't turn on and a few other odd things happened but he had it "programmed" by the dealer and vola...everything worked again!
Taking it to the shop tonight for an overheating issue (pump and thermostat were replaced in March)...maybe air is still in the system...I'll have them check the battery then.
I'll save you some time reading threads on RL and elsewhere about battery replacement/programming: Short answer is, if you want to make 100% sure the system is chosing the optimum charging profile for longest life, yes, you can opt to buy a reset tool (e.g. iCarsoft v2.0, $150) which will reset the Battery Management System with the battery type, install date, model etc. (or alternatively, pay the dealer or an indy to do so). If you simply replace the battery with a similar rating (e.g. 80 Ah), and do it yourself, chances are the car nor you will ever know the difference.
The battery production code is stamped into the negative post, top. It's four numbers, month and year of manufacture. Below is a picture of mine, made in week 14 of 2017. I also believe the date is printed somewhere on the label but I'm not near my car to go look. The original battery in my C2 is about four years old, and I plan to DIY it soon, most likely with an aftermarket AGM 80 Ah battery from Batteries Plus or similar. I just consider them lifed items and replace them proactively, at my convenience, lest I need to do it suddenly at short notice on a Sunday coming out of Church with my wife (BTDT
).
05-27-2021, 02:11 PM
#21
Intermediate
The battery in my 991.2 was replaced (I know it's not a factory one) but I'll have to check the date on the battery. I know it sat from March through June and the alarm was unplugged when I purchased it. It was bought from an action and the buyer said the action people could have unplugged that because it was going off...but he didn't do it or know it was unplugged. Also I don't think he replaced the battery when he bought it.
Buying a new battery will probably be a good investment as I will KNOW it's new and shouldn't have to replace it for 4 or more years. And just maybe, some of these electronic gremlins will go dormant for a few years!
05-27-2021, 02:25 PM
#22
Those symptoms happend AFTER he replaced the battery! I've had 4 M3's and never had an issue but had the batteries replace by an INDY shop when they needed it. 2 of them I didn't have long enough for battery replacement.
The battery in my 991.2 was replaced (I know it's not a factory one) but I'll have to check the date on the battery. I know it sat from March through June and the alarm was unplugged when I purchased it. It was bought from an action and the buyer said the action people could have unplugged that because it was going off...but he didn't do it or know it was unplugged. Also I don't think he replaced the battery when he bought it.
Buying a new battery will probably be a good investment as I will KNOW it's new and shouldn't have to replace it for 4 or more years. And just maybe, some of these electronic gremlins will go dormant for a few years!
The battery in my 991.2 was replaced (I know it's not a factory one) but I'll have to check the date on the battery. I know it sat from March through June and the alarm was unplugged when I purchased it. It was bought from an action and the buyer said the action people could have unplugged that because it was going off...but he didn't do it or know it was unplugged. Also I don't think he replaced the battery when he bought it.
Buying a new battery will probably be a good investment as I will KNOW it's new and shouldn't have to replace it for 4 or more years. And just maybe, some of these electronic gremlins will go dormant for a few years!
I thought of one more thing to help isolate...short of buying a new battery, you could put the car on a tender and see if any of these issues resolve themselves? So for example a small investment like a NOCO Genius or a Battery Tender unit from WalMart (either one is less than $40) you could allow the car to "see" the correct voltage, while not running. I didn't see if you had the car on a tender or not when in use. I was just thinking if you were going to get a tender anyway, or had one available, it would be a quick diagnostic/test.
Also, and since you said it was an auction car and "unplugged", it would be a very simple thing to check and VERIFY both positive and ground wires are FIRMLY in contact with the battery respective posts. Removing the posts and reaming them with a battery cleaner tool might not be a bad idea, to make sure they are making good contact, the connections are firm and tight, and you have them coated with some vaseline or similar to avoid electrolytic reaction. Obviously you need to take suitable precautions if you plan to DIY this.
But yeah replacing a sketchy battery or one with a murky history is not a bad way to give you a frame of reference to resolve electrical issues on these cars. Although if you find it's been replaced, or in decent shape (putting it on a load tester is another idea, but you have to either take it to a shop or store where they can put it on a load, or do it at the dealer or indy) maybe you can skip it and save the money.
05-27-2021, 03:49 PM
#23
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Hi - no record of flooding and the battery was checked first thing. They have been troubleshooting this with PCNA for a week now. The new PCM won't recognize the car as a Targa - only as a Cayman; and even then the navigation, bluetooth, and car play won't work. This is all quite disheartening.