cgfen

Trying to troubleshoot a TPMS problem

Many, many threads on this, but the vast majority seem to be dead battery in the wheel transmitter issues. This is one of the few threads that goes into the issue a bit more deeply. Thanks <JB in AR>

https://rennlist.com/forums/997-foru...t-failure.html

Current state = no pressure readout on on board computer (OBC) readout when in TPC mode. All I see are 4 dashes next to the tyre positions.
Troubleshooting step 1;
I assumed bad wheel mounted transmitters so I took a set of known good wheels / transmitters from another 911 we have.
Results = RF and RR display indicates pressures as expected. LF and LR indicate “Req” ???????????
Driving for ~ 40 miles and going through a few power on / off cycles made no difference. The RF / RR indicate pressure immediately, no “learning” necessary.

Troubleshooting step 2;
Swapped front wheels side to side.
Results = same as after step 1.

Assumptions;
1. I have at least 2 dead batteries in the original wheels that were on the Right side, may have dead batteries on original left side wheels too. That’s an easy fix by buying transmitters.
2. I may have something wrong with a sensor / antenna on the left side of the car.

Questions.
1. What the heck does “Req” indicate (see photo below)? It only appeared once I installed wheels with known good transmitters.
2. Can you point me towards a 997.1 TPC system schematic that I can review?

Other info;
1. I know where to buy more transmitters
2. I know I can disable TPC using durametric pro, I prefer to keep TPC

Thanks

Craig

cgfen

70 views and no one has an idea on what "Req" indicates??

jhbrennan

70 views and no response means at least 70 people don't know - you can't force an answer. I can't find anything about "Req." - I'm sure you've seen this in the owner's manual so I'm not telling you anything new. Good luck.

No tire pressures are displayed on the onboard
computer for wheels with faulty wheel
transmitters.

3putt4DG

I found a "Req" reference in a thread on planet 9.
http://www.planet-9.com/987-cayman-b...s-systems.html
Go almost all the way to the bottom 10/04/2010 9:37 pm
Most of the responses here say either the batteries are going dead in the sensors or ask if there is another set of tires nearby in the garage and the car is trying decide which ones to read.
Hope this helps.

Spiffyjiff

since you swapped wheels/put on a set of known good batts, i'd say a system issue vs. dead batts. are there no codes with the durametric? (other than presumably the generic TPMS fault that i see when i have my track wheels on which dont have sensors)

also, did you already try to disable via duramet? i've seen plenty of places on here and others that you need to remove the TPMS module also - which is behind the brake cyl? - in order not to get warnings. yes, you can toggle the TPMS via durametric but that is only half the battle, it will still give you warnings. would be interesting to hear otherwise.

cgfen

Thank you for this lead.

you are absolutely right, no answer is better than a guess or a wrong answer.

No, I'm trying to resolve the issue before going that route.

Cheers

Craig

Dadio

Interested if any final resolution reached on the issue of TPMS system failure. Have identical issue described in original post with new, tested and confirmed working , sensors. Having system diagnosed tomorrow in an effort to isolate which part of system is malfunctioning. Will post results if successful but would like any knowledgeable feedback from those with systems that have already been sorted out.

MagnusB

TPMS is a POS. One bad battery can throw the whole system.
I don't even have sensors mounted anymore.

Dadio

As a follow up, saved the cost of diagnosis and replaced the TPMS controller and system is working fine now. All sensors reading. As noted in my post, all sensors where new and tested and confirmed as sending data. Problem was data was not being received by failed controller. Cost for controller was $ 210 , estimated cost of diagnosis was $ 250 +.

Britzky9

TPC had to "re-learn" 3 times this weekend...maybe a failing controller? Not a fan of the idiot lights.

okbarnett

almost every tire shop has signal reader that measures strength of tpms sensor, just walk around the car

Britzky9

is that different than measuring battery life? Recent service said life in each wheel was good.

thanks!

Blue996Cabrio

I am aware that this is an old thread, but for reference I'd like to point out that the Req display is a normal display that indicates the required pressure. It is no indication that there is an error. It is accessible when not driving. There are two numbers, one is the required pressure for the front tires and one for the rear tires.

myronf

Dadio:

Any thing special that you had to do when you replaced the TPMS controller. Or was it simply plug and play. (take the old one out and replace with the new)

LRsCarreraS

Hi All- Been putting off addressing this issue. Bought the car in Nov of 20. Both PPI shop and my local Indy shop says the wheel sensors are fine. This is supported by PO providing receipt for all 4 sensors being replaced in July 2018. TPMS says it is in learning mode, but never learns….

Is there anything else I can do to reset the system? I see folks talking about the TPMS controller…unplug and plug back in?

The Porsche dealer in IN did all the work and let the PO take car with TPMS light still on saying “will need to drive to get the light to go out….!!!”

Two pints here:
- Yes I get that many systems calculate while in motion (my 991.1 C2S requires 15 MPH)
- Does the system really require 40 miles to learn?

Above shops couldn’t get the system to work and said it needs to be hooked up at the dealer…

Please Advise and Thanks.

LR