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Also in navi diagnostic mode I held down memory clear and now the amp has been removed from menu. As opposed to code clr. Did I do something I shouldn't have?
Hi Sans. Thanks for this info.
Can you tell. Me where jp1 is located as well as how to Access?
Thanks in advance!
Look at the second pic in my post...JP1 is in the center console. The pic shows you where it is.
Originally Posted by WylerLexus
Also in navi diagnostic mode I held down memory clear and now the amp has been removed from menu. As opposed to code clr. Did I do something I shouldn't have?
See documents attached.
I've titled the docs to be self explanatory...first check for codes in the Navi unit...next compare the codes you get to the list of codes provided...and last, suspecting you may get a code 74-40, the diagnostic procedures for that codes are attached.
Hi Sans,
if the ground at p3 was not properly grounded. wouldn't there be other components that are malfunctioning as well?
I just opened the center console and inspected the jp1 harness and all was good. it was tough to check continuity to p30 in the amp harness but i don't see how anything could have malfunctioned in the wire.
what does your diagnostic say is the next step?
i am also in the process of finding out if the amps i have do in fact work.
do you have to disconnect and reconnect power after reinstalling the amp? Or should it work without a hard reset?
Hi Sans,
if the ground at p3 was not properly grounded. wouldn't there be other components that are malfunctioning as well?
I just opened the center console and inspected the jp1 harness and all was good. it was tough to check continuity to p30 in the amp harness but i don't see how anything could have malfunctioned in the wire.
what does your diagnostic say is the next step?
i am also in the process of finding out if the amps i have do in fact work.
do you have to disconnect and reconnect power after reinstalling the amp? Or should it work without a hard reset?
if the ground at p3 was not properly grounded. wouldn't there be other components that are malfunctioning as well? No...the only thing grounded at P3 is the Amp...so if it wasn't connected properly then the only component that wouldn't work is the Amp. do you have to disconnect and reconnect power after reinstalling the amp? No Or should it work without a hard reset? Yes
There is continuity at p3 in the trunk.
There is power to all. Fuses and to the amp. Out of the three amps I have I do not. Know. If any work. What are the next steps Sans?
There is continuity at p3 in the trunk.
There is power to all. Fuses and to the amp. Out of the three amps I have I do not. Know. If any work. What are the next steps Sans?
When checking continuity of a wire, you're looking for two things...continuity obviously (that way you know the wire isn't broken) and resistance, which should be below 1 Ohm, ideally 0.5 Ohms.
If you checked continuity of the Ground wires from the Amp connector to P3, do you remember the resistance reading? If below 1 Ohm, then you're good, if it was above 1 Ohm, then there is an issue.
Let's assume you have Power at all the power wires and a good Ground to P3.
I believe you also checked continuity of the wires from JP1 to the Amp.
Last step would be to check continuity of the wires from JP1 to the back of the Radio.
If all the wires are good, and you have Power and Ground, and if at least one Amp of the three is good, then the only thing left is the Radio.
Realistically how much would you believe it's the Radio causing this issue?
Knowing that you tried a known good Amp, then this brings us back to all the wiring and the Radio.
You need to be really sure you have Power and a good Ground where these items are to be present.
If all the wiring is good, then the Radio is the only thing left...which brings me back to the above question...do you really think it's the Radio?
If the Radio can't send a signal to the Amp to turn on via the wire harness, then the issue would be the exact one you're having now...no sound.
You really need to confirm which of the Amps you have is good...easiest way is to pull them into your donor car that you tried the known good Amp from.
Even if the Amps you have are bad, it won't do anything to the donor car...the absolute worst case scenario is it blows a fuse...in which case get them a new fuse.
Once you know you have a good Amp, you can plug that in and forget about it. Then the only focus is the wire harness and Radio.
^^ Have you ever done your Ancestry test/check?!?! Einstein must have been somewhere on one of your branch, seriously man, you frikin impress the crap out of me!! You just know SO much and are so generous with helping others...
So I had a donor l vehicle come by and I tried the amp when we plugged it in it worked. So once again I confirmed that my problem is not the amp.
I think the last thing to check is the radio since I'm getting lower to amplifier wiring harness and all fuses seem good to me with proper voltage and continuity.
How do we diagnose the radio to see if sending signal to amp? Or what connectors need to be working.
Some say the radio can short out at the aux and to try plugging that in.
I think at one time I can remember sound coming back when I did do that.
So I had a donor l vehicle come by and I tried the amp when we plugged it in it worked. So once again I confirmed that my problem is not the amp.
I think the last thing to check is the radio since I'm getting lower to amplifier wiring harness and all fuses seem good to me with proper voltage and continuity.
How do we diagnose the radio to see if sending signal to amp? Or what connectors need to be working.
Some say the radio can short out at the aux and to try plugging that in.
I think at one time I can remember sound coming back when I did do that.
Ok, now that confirmed that one of the 3 Amps is good, plug it in and that should take care of the rear of the vehicle...since you have Power and Ground to the Amp.
The only way that the Radio controls the Amp is through the wire harness that runs down the center of the vehicle through JP1...which you checked that connector already.
So if everything from JP1 to the Amp is good, and you know the Amp is good, and you have Power and Ground at the Amp, then basically the issue has to be from the Radio to JP1.
If you want to try and disconnect the Aux port to see if that is the issue, then disconnect connector Q31, which is right at the Aux port, or connector JQ3, which is between the Aux port and the Radio.
Here's the connector locations below:
As you can see they are both in the center console in the vicinity of JP1.
explanation on how to disconnect/replace Harness Q31 above as @Sasnuke shows.
I will unplug this ASAP and get back to everyone to determine if there is a short in my aux line causing now sound.
I have had the
Thank You for your reply Sir, above is the screen shot from the scan. I didn't see the AMP error code.
I talked to the technician again today and asked for any proof if the fix was actual done or not and he declined to provide any. Again, reiterated to clean that connection but this time added that the connector is below the radio and goes along the console to the back of the car. I am planning to take that apart one more time this week end.
My diagnostic screen looks just like this regardless of the amp being connected or not, 2014 is250 non-Ml.
I have check absolutely everything mentioned here several times cleaned every mentioned connector. I found a passed amp report on the truck severaldays after getting the car stating the amp is in good condition, upon removing the head unit I found it had hand written numbers on the top as if the previous owner purchased a used one. I'm running out of patience and don't want to send the amp out my self because obviously someone sent it out already and is "good". I checked the amp harness and it has power while grounding my negative lead directly to the body, there are 3 black wires on the amp harness but I didn't seem to get any readings grounding from those, will have to look up where this P3 ground is. I seen an another post where someone was blaming the sos button muting the amp and the dealer just removed the wire and he was all set
My diagnostic screen looks just like this regardless of the amp being connected or not, 2014 is250 non-Ml.
I have check absolutely everything mentioned here several times cleaned every mentioned connector. I found a passed amp report on the truck severaldays after getting the car stating the amp is in good condition, upon removing the head unit I found it had hand written numbers on the top as if the previous owner purchased a used one. I'm running out of patience and don't want to send the amp out my self because obviously someone sent it out already and is "good". I checked the amp harness and it has power while grounding my negative lead directly to the body, there are 3 black wires on the amp harness but I didn't seem to get any readings grounding from those, will have to look up where this P3 ground is. I seen an another post where someone was blaming the sos button muting the amp and the dealer just removed the wire and he was all set
Welcome to the forum!
Maybe to clarify one point...in this thread forum member WylerLexus jumped in with similar issues on his 2IS 2006 IS250. So any post from him, or directed to him, are for a 2IS. Everything else in the thread is 3IS related.
You mentioned P3, which is the Ground on the 2IS, on the 3IS it's PC.
On the 3IS Amp connectors, there are 8 Black wires across the three connectors, none of which are Power or Ground.
If you'd like to check Power and Ground I've attached some pics below.
The two Brown wires both go to PC, which the location is in the second pic.
I would check Power at the blue and beige wires with your meter on a good ground point, and then double check to see you get the same reading using both Brown wires as your Ground.
This will tell you if both Brown wires are good along with PC. If the readings are basically the same between the Brown wires vs. a known good Ground point, then you don't need to check PC.
The voltage reading at the blue and beige wires should basically be Battery voltage, 12.XXV.
In regards to the SOS Button, while it could stop sound from the audio system by constantly sending a Mute command, that will have no effect on the Amp appearing in the diagnostic menu. The Amp should still appear and pass with an OK.
If the Amp is missing from the diagnostic screen, then there is definitely an issue between the Radio and Amp, or the Amp itself.
Ok, now that confirmed that one of the 3 Amps is good, plug it in and that should take care of the rear of the vehicle...since you have Power and Ground to the Amp.
The only way that the Radio controls the Amp is through the wire harness that runs down the center of the vehicle through JP1...which you checked that connector already.
So if everything from JP1 to the Amp is good, and you know the Amp is good, and you have Power and Ground at the Amp, then basically the issue has to be from the Radio to JP1.
If you want to try and disconnect the Aux port to see if that is the issue, then disconnect connector Q31, which is right at the Aux port, or connector JQ3, which is between the Aux port and the Radio.
Here's the connector locations below:
As you can see they are both in the center console in the vicinity of JP1.
Hi Sasnuke,
I disconnected q31 in the rear of the center console where the air vens come out.
The sound is still no coming through the speaker system.
could i have a short with out 74-40 error?
what further diagnosis can be completed? I have had my Navi screen out before to install an output to the sat-am function using a grom unit for ipod navi and steering wheel control.
thanks,
Wyler
Hi Sasnuke,
I disconnected q31 in the rear of the center console where the air vens come out.
The sound is still no coming through the speaker system.
could i have a short with out 74-40 error?
what further diagnosis can be completed? I have had my Navi screen out before to install an output to the sat-am function using a grom unit for ipod navi and steering wheel control.
thanks,
Wyler
Do you still have the Grom Unit connected? If so I suggest removing it, just in case it could be causing an issue.
In reference to code 74-40, you can refer to the diagnostic Steps 3 & 4 in one of the previous post attachments and blend them together to check the speakers a lot easier...just in case there is a short and the code isn't popping up.
In Step 3 they want you to disconnect he Amp connectors and all speaker connectors, then check each speaker wire to Ground...to make sure no wires are shorted to Ground.
If you were to disconnect the Amp only and check the two wires (per speaker) for resistance, you should get the same resistance reading as in Step 4, approx. 4 Ohms if you have the system without the Front Center Speaker, or 6 to 10 Ohms if you have the system with the Front Center Speaker. I'm guessing you have the one without.
When you get the resistance reading, if it's within spec then the speaker is good...you can then leave one meter lead connected to either speaker wire and connect the other lead to Ground...this will tell you if the speaker or wires are shorted to Ground (open circuit is the expected result...so no resistance).
If there is no short to Ground, then the speaker and wires should be ok.
By short cutting Step 3 like this the only thing you won't know is if a set of speaker wires are shorted to each other...meaning the positive and negative wire for a single speaker are touching each other.
01-05-22, 02:00 PM
