Poor radio reception 996.2 once the engine is started. Where the antenna amplifier is located?

[alex222]

Noticed on a cold 996.2 the radio plays back great. With the key in position 2 - great. Once I start the engine up- the reception is very poor and only 2-3 radio stations can be heard OK. Then after some time the engine is OFF the radio works great again. If the radio is OFF during the engine start after the engine is shut off the radio reception is OK. Suspected the radio head unit. Swapped the radio to another one. Same thing. It's not the radio head unit. Checked the antenna diversity splitter in the RH A-pillar. Don't see any +12V wire cable coming into it. It just splits the antenna signal to the LH and RH antenna wires in the windshield. Suspecting the antenna amplifier antenna amplifier 996 647 124 00. Anybody knows of where is it located at?

[JFP in PA]

Ever think it could be the ignition switch?

 

The antenna amplifier is located on the right A-pillar, behind the trim which is easy to remove

[alex222]

Less to think it's the ignition as the ignition on my pup is a brand new. No any signs of use. I think it might be the amplifier which is dying. I see the wires and the antenna cables from the radio are going from the center console to the left behind the instrument cluster, so the Q is where the amplifier is located? Behind of the instrument cluster, above the pedals, or on the fuse box (LH) wall?

 

If you read the post for the 996.2 in right A-pillar it is the antenna SPLITTER, not the amplifier.

Edited February 3, 2023 by alex222

[JFP in PA]

According to Porsche, item #24 in the pillar is the "antenna booster", while the item you posted the photos of is item #27 is the "Antenna Diversity Control Unit" for the PCM navigation

[alex222]

You right. 

 

I am having the #26 instead of #24 though - I have the Nav unit. So the question remains of where the #27 Control Unit is located at? 

Edited February 3, 2023 by alex222

[JFP in PA]

19 minutes ago, alex222 said:

You right. 

 

I am having the #26 instead of #24 though - I have the Nav unit. So the question remains of where the #27 Control Unit is located at? 

Passengers side footwell.

[alex222]

Thank you.

 

The replacement control module came in today. I got a used module and it behaves exactly the same as my original. The radio plays perfectly all the stations with the key off and when the key in position 1. Once I start the engine the reception for the radio is gone for almost all stations. After I shut off the engine no reception remains for a few minutes maybe 2-3 then I turn on the radio and the reception is perfect on all stations. When I had taken off the power cable from the module - no reception just noise on any radio stations. The power on the power cable to the module reads +11.5V when radio is on and engine off and +13.9V when engine is on. I also already have had replaced the PCM head unit - both head units show the radio stations reception issue exactly the same way.

 

The only other thing involved in the radio reception to replace next is the amplifier in the RH A-pillar.

 

Anybody have had experienced this issue I am having?

 

 

 

Edited February 23, 2023 by alex222

[KapCoupe]

You're certainly not crazy, Alex.  I've been having the identical symptoms for the past year starting when I replaced my original radio with the new PCM+ double DIN unit.  Neither the dealer that did the swap nor I have been able to figure it out.  I also replaced the signal amplifier in the right pillar with no change to the issue.  It would be great if someone had a solution for this nutty problem.

[alex222]

Have you ever plug your original radio back in?

[alex222]

Solved. 

 

My problem was the AM/FM antenna amplifier (WHITE) in the LH A-pillar was dead and the FM antenna amplifier (BLACK) in the RH A-pillar was dying. 

 

 

I noticed in the parts diagram than my car which is with the PCM2.0 Nav is having 2 antenna amplifiers (in each A-pillar) unlike the cars with just radio which have only one antenna amplifier in the RH A-pillar, and the antenna amplifiers for the PCM Nav unit are different from the one for the regular radio. I opened up the cover of the LH A-pillar and disconnected both antenna cables and started the engine and the radio was working with the engine ON. So when I was waiting on the LH amplifier 996 647 117 00 to arrive, on the two engine starts out of 10 the reception issue on the radio came up and similarly after a few mins after the engine was shut off the radio was working again. So I have had ordered the other RH amplifier 996 647 118 00 as well. The RH amplifier arrived first and that was perfect, so I had a chance to replace the dying amplifier first to make sure the replacement is good at all times and not shadowed by the LH amplifier. I did 2-day about 10 engine starts-ups and rides and the reception on just RH amplifier was good. I also learned that just one amplifier is not good enough for a good radio reception, when I was passing the low grounds, the reception was slightly not perfect. So it was no any issues on any engine starts. 

 

Then the LH white amplifier arrived, and I connected it and did like 10 engine starts/idle and the reception was perfect, no any issues. Then I took the pup for a spin and headed to those low grounds where on just one amplifier the FM perception was slightly w/ some static noise. And passing the same low ground spots the radio is perfect now. 

 

Achtung!

 

The antenna plugs are easy to break! They have the little bar on top it's the only place to grab them to pull out and I had broken that tiny bar.

 

 

The cause is the securing pin is to tall and the force to pull the plug out and break the little plastic bar is greater than to unpin it. Use a 1mm flat screwdriver.

 

 

1. Unplug 2 radio cables which go to the control unit.

2. Insert the flat screwdriver in the OUTER connector (facing YOU) so it lifts up the cover where the pin is. Just insert the screw driver straight. DO NOT PULL UP!!!

3. Pull the plug out. The screwdriver will come out too.

4. Unscrew the amplifier. It is held by 2 x 25 Torx screws.

5. VERY gently turn unscrewed amplifier facing parallel to you (parallel to the windshield) so you can insert the 1mm flat screwdriver into the INNER connector from aside.

6. Holding the amplifier pull the inner plug out. BE VERY CAREFUL! At no points do not pull the gentle flat antenna cable out from the windshield. If you rip off the antenna cable it will be a WAY bigger issue!!! 

 

 

 

Reassemble in the reverse order.

 

1. Plug the inner antenna connector first

2. Screw in the amplifier to the pillar

3. Plug the outer antenna connector

4. Plug in the antenna cables to the control unit.

5. Try the radio/start the car

6. Take off the black masking tape from the old amplifier and put it on the new amplifier.

 

 

Edited March 4, 2023 by alex222