Hello all

My 2012 CT200h with Navigation has a radio issue. I've replaced it three times, but still no dice. Here are the symptoms:

What works
-The navigation screen flips up and stays on the map view when the car is on
-Back up camera works
-Mouse centers when the car is turned on or off
-Radio lights work and dim accordingly
-USB does charge my phone, but painfully slow (1% per 10 min). My phone does stop playing audio aloud when its plugged in, suggesting the USB port does behave like a receiver
-When I press the phone call buttons on the steering wheel the nav screen switches to a call screen with a num pad.
-Pressing and holding the SOS button on the ceiling the warning comes on that my subscription is up. This is the only noise the speakers have made.

What doesnt work
-Anything that a standard radio would do
-Anything in the infotainment center
-Mouse
-The whole system is effectively dead besides the back up cam and nav screen

What I've tried
-Checked, sanded, and ran continuity tests on the following fuses:

• Rad 1 under the hood
• S Horn under the hood
• Amp 1 and 2 under the hood
• Rad 2 under dash
• Panels under dash
• Meters under dash
• Power Outlet under dash

-Checked impedance of all speakers at the amplifier connection under the seat. See the break down section below.
-Tapped each speaker from the amp connections with a 9 v battery, all made noises.
-Checked to make sure the amp has sufficient power and ground. (note they were 14V+ while the car was running and only 12V+ when turned off)
-Replaced the radio headunit with three different used ones that supposedly worked
-Pressed and held the power button for 15 seconds
-disconnected the 12V battery for 20 min
-Recently (~July 2022) ran a load test on the 12V battery. Load test nearly failed. Battery will be replaced soon.

Impedance and Voltage Checks
H57 Connector at Amplifier:
Rear Left Door (Pin 4 to 11): 3.2 ohm
Rear Right Door (Pin 5 to 12): 3 ohm
Front Right Door (Pin 9 to 10): 3 ohm
Front Left Door (Pin 3 to 8): 3.2 ohm

H58 Connector at Amplifier:
Woofer (Pin 1 to 2): 1.4 ohm
Front Left Dash (Pin 3 to 9): 3.3 ohm
Front Right Dash (Pin 4 to 10): 3.7 ohm
Front Center Dash (Pin 8 to 7): 3.4 ohm

H56 Connector at Amplifier: (Checked for voltage using pin 5 'Body Ground')
Vehicle Speed Signal (Pin 2): 14.3V
MOST Communication Wake-up Signal (Pin 3): 14.7V
MOST Communication Signal (Pin 4): 0
MOST Communication Signal (Pin 6): 0
MOST Communication Wake-up Signal (Pin 9): 0
MOST Communication Signal (Pin 10): 0
MOST Communication Signal (Pin 12): 0

H59 Connector at Amplifier:
Power Source (Pin 1 to 2): 14.9V when car is running, ~12V when car is off
Power Source (Pin 3 to 6): 14.9V when car is running, ~12V when car is off

Connectors at radio:
I lost the specific voltage readings, but the head unit had power and ignition.

Additional Information
-The used radios I installed did not work, however I could hear noises coming from the disk changer for a couple of seconds when the car was turned on or after replacing the fuse.
-I bought the car like this, never heard the speakers work.
-The faceplate number is P10041

My plan
-Cry
-bench test spare radios
-replace the 12V battery
-replace the under seat amplifier

If anyone can help or has information please share!

 

Updated the original post and deleted comment

 

I think my problem may be similar to the unanswered CT200hforum thread here: 2012 CT200h w/ nav - AMP reprogramming?
I will reach out to the poster. After digging around other Lexus forums, it may be possible the head unit is going into a protection mode, which would fit with the units only making sounds from the CD player when newly installed. Does this make sense?

 

Did you ever resolve this? Having the same issue with a 2011 CT with the same faceplate number. Tried everything but swapping the radio, as multiple posts seem like that's not the fix.

 

Nothing. I haven't worked on it since the post was last updated because of the cold. I have another used radio to try throwing in there. we have a couple of warm days coming up so I may try it. fingers crossed but I doubt

 

Updated original post to include:
-Voltage checks at back of head unit connectors
-12V battery nearly failed load test. Will be replaced later today.

As other users have suggested I may try to find a used amplifier to throw in there. I am hesitant to suspect the amplifier because the SOS button works.

 

did anyone find any solution for the problem. I have been suffering with the issu with no answer