How Does It Work

[40something]

I have recently bought a 52 plate avensis under warranty, with traffic avoidance and both I and my local Garage are suffering from a lack of information. It has been in a number of times without any clear course for the investigation.

The Traffic avoidance shows "NO TMC RECEPTION" virtually all the time. Only on the very rare occasions (only two journeys in 6 months) has it not shown that indications and when it has I've been puzzled by its operation. Here are the questions I require answering:

Who broadcasts the Traffic signals?

Is the signal received and processed through the Radio or the sat nav sytem?

Where is the aerial?

Is the carrier signal broadcast permanently or only when there is a traffic Alert?

How frequently are the reports updated?

Where are the connector breaks (I suspect a loose or broken connection)?

Is there a manual available for download?

I'm disappointed that even garage electricians seen to suffer from lack of information. However I cannot fault their eagerness to help. Independently, they will try through their company channels but I hope this forum will provide a breakthrough.

I await eagerly

[tezza]

The signal comes off a sub carrier on Classic FM.

In my 6 months experience, the reports are few and far between. When they have occured you get to the incident only to be told it has now cleared.

The system obviously needs some development, so I wouldnt worry too much about whether you have it or not.

Basically it's a load of cr@p.

[jimmac]

The system is actually quite good but it only works with the TBT navi - if you've got the full map navi kit then the function isn't available.

[keithwr]

I was getting exactly the same 'rare TMC Reception' on my recently bought 02 avensis. Like 40Something I suspected a loose connection. However I found that although places that gave TMC Reception were rare the were repeatable. i.e. if I returned to a place where I had seen TMC reception then I got it again. So it didn't seem to be a loose connection which sometimes made so much as a very week signal feed to the ETA unit.

Like you I found the Toyota dealers mechanics keen but with virtually no information.

The ETA receiver is a small box bolted to one end of the SAT NAV unit. The mechanics found out that the aerial is a strip fastened to the inside top of the windscreen. I demonstrated to them that unplugging the aerial lead and pushing one end of a couple of metres of fine wire into the aerial sockect gave TMC reception and collection of traffic hold up info. The ETA unit has a 2 colour LED visible if the canvass cover is removed. This show red if no signal being received flashes red/green with a weak signal and solid green with an adequate signal.

The Traffic info service is provided by ITIS Holdings (www.itisholdings.com) and is transmitted on a sub carrier on the Classic FM network. The carrier is always present so we should only get NO TMC Reception when we go into a radio blackspot.

My car has been into the dealers to have this fixed twice now, the last time for four days. The first time the mechanic tried changing the ETA unit which didn't cure the problem. When I went to collect the car and heard what he'd done he said he suspected the aerial / lead as that was the only other component of the system. So I tried my bit of wire confirming that was the problem. He said he would order the aerial and lead and phone me to book my car in to have it replaced. Problem was when I took it in they gqave the job to a different mechanic who totally missunderstood what the prblem was wasting 1 day. When I corrected this misconception they said ok they would keep the car and fit the aerial and lead. They then found the part that had been supplied was the ordinary radio areial and lead, so we wasted two more days while they ordered the correct part. When that came they found that it was the stick on cover that attatches the aerial to the insdie of the windsreen but not the aerial itself, and that they couldn't get a delivery date for the aerial. I'm still waiting. :(

[GrantR]

I agree with Tezza that whilst in theory the system is a good idea, in practise it is a different story. I don't have a problem with reception but on a 450 mile round trip to Yorkshire from Surrey last week I had countless warnings of traffic ahead only to find them cleared by the time I got there, so I'm not going to bother rerouting unless the radio traffic announcements confirm it (not that they are always correct either though). Some work needs to be done on the "Real Time" claims of the system, although I'm sure there will always be a time lag between the information being collected and the data being broadcast.

[beagle]

I forget where I heard this (dealer), but I seem to remember that the data for the TMC is obtained from participating haulage firms lorries having a transponder of sorts on board that signals whenever the vehicle goes below a certain speed.

Could be hogswash of course ...

I have found that the TrafficMaster system is more reliable than the TMC.

The TM system gets its data from roadside detectors ?

[mark.wallace@mawallace1.d]

Yes - the information comes from lorries and bus companies - see www.itis.co.uk - who supplies info re the TMC reception.

A report was published recently, which stated that Traffcimaster was better then the TMC system, but itis are currently considering a legal challange!

I find that both systems have their failings - I use both systems hand in hand!

[John]

I have recently bought a 52 plate avensis under warranty, with traffic avoidance and both I and my local Garage are suffering from a lack of information. It has been in a number of times without any clear course for the investigation.

The Traffic avoidance shows "NO TMC RECEPTION" virtually all the time. Only on the very rare occasions (only two journeys in 6 months) has it not shown that indications and when it has I've been puzzled by its operation. Here are the questions I require answering:

Who broadcasts the Traffic signals?

Is the signal received and processed through the Radio or the sat nav sytem?

Where is the aerial?

Is the carrier signal broadcast permanently or only when there is a traffic Alert?

How frequently are the reports updated?

Where are the connector breaks (I suspect a loose or broken connection)?

Is there a manual available for download?

I'm disappointed that even garage electricians seen to suffer from lack of information. However I cannot fault their eagerness to help. Independently, they will try through their company channels but I hope this forum will provide a breakthrough.

I await eagerly

Hi

I've just bought Avensis too last week with eta, the on view display tells me what road I'm in but when I go into menu i get no symbol with traffic information does yours? I'm going on the M42 next week and there's always a hold first time i'll be able to test it out. Looking at some of the comments on this forum many seem to say it's hit & miss whever it works or not. keep me posted if you find out the problem.

Cheers

John

[40something]

This posting is to close off the topic and to announce that my TMC is finally working.

Thank you, Keithwr for providing details as to how it is wired within the car. I too managed to get a better signal by using a piece of wire and although I did not need to demonstrate it to the garage it enabled me to confirm that it was a wiring problem.

As I stated in the original posting I did approach the company and WAS NOT impressed. I had a very shirty response from Toyota GB. They stated that they would not be able to help me without me providing them with with my car reg number and the address of the garage that had been trying to help me. I did not get any subsequent response, even to the request as to the part number for the manual for the traffic avoidance sytem.

Without a response I approached my Garage again and asked them if Toyota GB had contacted them. Some communication had taken place.

To cut a long story short I eventually booked the car back into the garage and after getting the correct loom, I now have a working sytem. I now get reception almost all the time.

In Summary, FULL MARKS to the garage for being very helpful, even letting me have the courtesy car for the weekend, rather than having the inconvenience of bringing my car back the following week when they had the correct part. NO POINTS for Toyota GB for being so impersonal and not answering ANY of my questions.

Thank you to all who replied and provided some very good information as to how the complete system works. I learnt quite a bit when I followed some of the trails on the net. I have certainly learnt that fellow users are excellent in helping solve problems.

Once again THANKS. :)

[keithwr]

40something, I'm pleased if I was of some help. To the forum, I apologise for not coming back to complete my story. The St Albans Toyata dealer did eventually get the right parts, i.e areial and lead and fit them. It cured the problem and like 40something I now get TMC reception nearly all the time.

Keith