XM Radio Losing Signal

Discussion in 'Gen 4 Prius Audio and Electronics' started by Zdcatc12, May 5, 2018.

  1. Zdcatc12

    Zdcatc12 Junior Member

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    I have a 2017 that has a problem with XM losing signal for no reason, i.e. driving down the interstate on clear day and it loses the signal. This is random, but happens often, and usually for only a few seconds at a time.

    I have had XM on my last 4 or 5 cars and never had this issue, though they were all GM products. Is this common and something that would be fixed under warranty (I'm afraid it wouldn't happen when they are checking it). I did searches on here and saw that it happened on someones 2012, but since that is a prior generation, I didn't think the issue would be the same, though I may be wrong.

    Thanks.
     
  2. Elektroingenieur

    Elektroingenieur Senior Member

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    It’s hard to say if the problem you describe is a common one: like other automakers, Toyota doesn’t generally disclose warranty claim statistics, and since the XM receivers in most cars aren’t used after the free trial period, a failure might never be noticed.

    In principle, an XM-related defect would be covered under the New Vehicle Limited Warranty, subject to its terms, though Toyota discourages repair efforts when the dealer can’t reproduce a problem and there aren’t any stored diagnostic trouble codes (DTCs).

    The Repair Manual (available by subscription to techinfo.toyota.com) includes a troubleshooting procedure for “Satellite Radio Broadcast cannot be Received,” which also covers poor reception, but it may not help much for an intermittent problem, for which DTCs like any of the following—if present—would be more helpful:

    B15BA XM Tuner Malfunction
    B15FE XM Tuner Antenna Disconnected
    B15FF XM Tuner Antenna Short​

    You (or a dealer) can check for DTCs using a Toyota Techstream diagnostic system or, for a problem like this, the built-in diagnostic mode of the navigation receiver assembly. I’ve posted the steps to access the latter before. Once you’re at the Service Menu, press Failure Diagnosis, then System Check. There might also be a DETAIL button, for more information. Don’t press Memory CLR or Code CLR to clear any DTCs you might find, since the dealer will also need to see them.
     
  3. RRxing

    RRxing Senior Member

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    Random and only for a few seconds probably means hitting some "dead spots" with the satellite connection. I get one or two occasionally, usually when traveling under an overpass, but also in certain sections of main roads.
     
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  4. sam spade 2

    sam spade 2 Senior Member

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    And it could be a problem just with the one channel that you listen to most of the time.
    Also note that tall trees can disrupt the signal sometimes too.

    If it persists, the antenna and it's connections needs to be checked.......at a minimum.
     
  5. Elektroingenieur

    Elektroingenieur Senior Member

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    That may very well be the trouble area—but checking is easier said than done.

    To get access to the antenna and the three antenna cord sub-assemblies involved in XM reception, the roof headlining and the lower instrument panel sub-assembly must be removed. Toyota’s Flat Rate Manual allows a combined 3.6 hours for removal and reinstallation; @Erik Owens might be able to tell us how long it really takes.

    There also isn’t much to check: the technician could look for a loose connector or gross damage like a pinched cable, but measuring the electrical performance of the antenna, its built-in amplifier, or the cable assemblies would require RF test equipment that dealers are unlikely to have. Just as importantly, Toyota hasn’t published engineering data for the system, like expected signal-to-noise ratio or cable loss—the Electrical Wiring Diagram doesn’t even show all of the connectors.

    The Repair Manual procedure, after some basic tests, says to replace parts one at a time, in a certain order, until XM reception works. I’d be surprised to find a dealer willing to do this for an intermittent problem that couldn’t be reproduced on demand. It would be different with a diagnostic trouble code, of course.

    I don’t mean to imply that there isn’t a defect in the car, by the way, just that finding it—within the constraints of Toyota’s warranty policies, servicing strategy, and dealer capabilities—could be difficult.
     
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  6. Erik Owens

    Erik Owens Member

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    Normally there is no pinched cable. Ive ever only done one in a 4Runner period and it was corroded at the connection to the internal parts. Flate Rate manual for Toyota is only for warranty which is what your 2017 should still be good. The wire goes from the A pillar connection to behind the radio obviously and then back to the antenna on the back of the roof which there are two more cables I think. The head liner would have to come down to inspect since that sucker is glued and taped to the headliner to keep it in place so if it is bad whole new headliner. If its just the cable from pillar to radio the top dash would have to come out. Headliner looking at almost 7 to 11 hours depending how tight it is. This is taking out front and rear seats and pillar panels, etc. The top dash for most Prius if older is about 1 hour to newer which is about 3 hours give or take. The more crap they put in the dash dictates how much time we ask for. If we can find it in Mitchell Pro Demand then we go with that. Pro Demand sadly doesnt have every little task so we try to go for the next assembly that is in that area. So headliner for 2017 is 4.3 hours. Top dash portion is 1.0 and lower is 4.0,....if done to gain access to A/C Evaporator core nice person it would be 7.9 but you get my jist.
    Yes warranty pays less and you dont have to worry about it but its a new car and we all learn the nuances of taking that sucker apart all the same. They would have to diagnose the concern first which is why we have that special tool. Plus we make sure the XM radio subscription is good so which its free for how ever many months then we narrow is its the cable or the antenna which is not an easy task but being patient pays off.
    BTW I read a tiny bit into and I want to say your XM tuner is under the dash. Do this which you can go into diag mode to see if you have any codes in your telematics. So with Start/Stop switch make sure the car in ON mode not READY ON. Press and hold your audio button and turn your headlights full on and full off three times. Your display should change and give you diagnostic mode where you can view your telematics DTC. Just dont be a douche and clear them or if they are in history give a huge bit of grief to Toyota. If they are current again dont erase, write them down. Tell Toyota and explain when and where your XM is going out at. There may be a radio update. If you have codes there may be a component you will have to replace. Either way you got a full on explanation from a Toyota Expert to make your way a little smoother. We are not all stealerships because of a few dicks.
     
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  7. axle2152

    axle2152 Active Member

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    I'll throw my 2 cents in. XM actually has fewer satellites than Sirrus, yes same company but different tech. The XM satellites are on the southern sky, so anything that could block the sky from the south. So terrain, buildings, etc can all play a role here. Every satellite radio I've used whether it was factory equipment or aftermarket has cut out and at times you'd think there would be no reason.

    The question is how often and does it happen in the same areas in your commute?
     
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