Volvo V70 - MY 2000 Immobiliser Fault

If you are not a PicoScope user and want advice with a diagnostic problem then post here. Forum members may be able to help.

Volvo V70 - MY 2000 Immobiliser Fault

Postby STC » Wed Aug 16, 2017 4:00 pm

Vin VV1LW 56C6 X259 5660.

This will start when it feels like it and will just crank at other times. Often it will fire up and die seconds later just like an immobilised VAG Car.

Each time it will throw
720A - Communication Between PCM & Immobiliser Faulty. The fault sets at Ignition on before cranking.

PCM & Immobiliser power supplies, connector pins are tight and shiny like new.

I have taken 2 wave forms at Pin 4 Immobiliser unit, one with it unplugged and I believe I have 2 way communication.
Volvo v70 2000MY Immo 1.psdata
(2.45 MiB) Downloaded 14 times

Volvo v70 2000MY Immo 2.psdata
(2.65 MiB) Downloaded 12 times


Can anyone throw some light on this for me?

thanks
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Volvo V70 - MY 2000 Immobiliser Fault

Postby victor2k » Wed Aug 16, 2017 8:42 pm

Hello,
Fault code 720a is immo fault code:please check immo coil/immo module for bad soldering,bad contacts.
Regards
victor2k
TwoWaves
TwoWaves
 
Posts: 165
Joined: Thu Jan 28, 2016 9:17 am

Re: Volvo V70 - MY 2000 Immobiliser Fault

Postby STC » Wed Aug 16, 2017 9:43 pm

Hi Victor

check immo coil/immo module for bad soldering,bad contacts.


I did check the Module connector contacts, but did not open the box. I can tomorrow.

As for the Immo Coil, the antenna for the transponder - I have read that these are a very common failure. However I did not go towards that because of the fault code description. Cutting the Signal wire from ECU to Immo Module gave me the exact same fault code hence my attention was focused only on the 2 modules and that wire.

At the point that I could see, or guessed that 2 way communication is taking place it was time to stop and ask for help or give the job to a more capable technician. I don't have Vida for diagnosing this but I have just placed an order to purchase it.

I have just looked at the Fault code table in KTS and I see that there is only one Immo code listed. Or is this a shortfall in KTS ??

Is it the case that in these older cars that they covered any failure in the entire Immo system with on code ???

Thank you once again Victor for the guidance.
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Volvo V70 - MY 2000 Immobiliser Fault

Postby victor2k » Wed Aug 16, 2017 9:52 pm

Hello,
On a 2000 year diagnose don't expect more...
You must check entire chain of immo for this fault code. :(
Here is a fault description from Vida.
Attachments
720a.rar
(121.22 KiB) Downloaded 16 times
Last edited by victor2k on Thu Aug 17, 2017 9:10 am, edited 1 time in total.
victor2k
TwoWaves
TwoWaves
 
Posts: 165
Joined: Thu Jan 28, 2016 9:17 am

Re: Volvo V70 - MY 2000 Immobiliser Fault

Postby STC » Wed Aug 16, 2017 10:12 pm

You must check entire chain of immo for this fault code. :(


Now that is possibly / hopefully is my ticket to the moon

Thanks again Victor.
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Volvo V70 - MY 2000 Immobiliser Fault

Postby volrem » Thu Aug 17, 2017 9:03 am

To be precisce this car is MY1999 and not MY2000. It doesn't change much but still.
And there is a typo in that VIN. first letter shoulb be Y not V

ECM-720A
Code: Select all
This diagnostic trouble code (DTC) indicates that the configuration between the engine control module (ECM) and the immobilizer does not correspond. The immobilizer transmits the VIN code to the engine control module (ECM) at start attempt. Diagnostic trouble code (DTC) ECM-720A is stored in the engine control module (ECM) if the engine control module (ECM) interprets the code as faulty or missing. The engine control module (ECM) will not allow the engine to be started.


Do you have any codes in IMMO module (not ECM)?

What's the immo related history of this car?
volrem
TwoWaves
TwoWaves
 
Posts: 192
Joined: Fri Jan 03, 2014 5:43 pm
Location: Estonia

Re: Volvo V70 - MY 2000 Immobiliser Fault

Postby STC » Thu Aug 17, 2017 8:46 pm

To be precise this car is MY1999 and not MY2000. It doesn't change much but still.

Indeed it was registered as new here in the Uk in 1999. However when I went looking for Factory Wiring Diagrams on Google the 1999MY did not match so I 2000MY and they did match. It was a few days ago now.

And there is a typo in that VIN. first letter (shoulb) should be Y not V

Indeed, well spotted and I stand corrected, that should be a Y not a V

Do you have any codes in IMMO module (not ECM)?

KTS & Snap On is all that is available to me (I forgot about Autocom) and no they do not delve into the IMMO as much as we would like.

What's the immo related history of this car?


Regular customer, known to us. Reliable Information is that it can not be relied upon to start. Sometimes it could be fine for a week other times not. It was fine for at least 5 days in the workshop, it would start several times a day.

Then it would not start for 3 days, after taking the captures with the scope which involved removing the IMMO and plugging it back in it started. Beating the IMMO box with a screwdriver handle had no effect, it continues to start for now.

I have only one key and remote for Central Locking which is not working and the man is not complaining about that.

I will have the use of VIDA in a few days, then I can look at Live data etc. to get a better understanding.

Thank You for the information - Very Kind - I will reply again when I have more.
Last edited by STC on Fri Aug 18, 2017 7:57 am, edited 1 time in total.
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Volvo V70 - MY 2000 Immobiliser Fault

Postby STC » Fri Aug 18, 2017 12:11 am

The immobilizer transmits the VIN code to the engine control module (ECM) at start attempt.


I disagree. It does so at Terminal 15 Switch on, not before or after. From what I have measured.
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Volvo V70 - MY 2000 Immobiliser Fault

Postby volrem » Fri Aug 18, 2017 8:06 am

STC wrote:
The immobilizer transmits the VIN code to the engine control module (ECM) at start attempt.


I disagree. It does so at Terminal 15 Switch on, not before or after. From what I have measured.


Maybe. This is a quote from service manual. And it depends what someone defines start attempt to be.

Anyway this DTC mean that there is communication error between ECM and IMMO. Don't know whether it's real communication problem or just data doesn't match.

Looking at live data in ECM and IMMO can steer you in right direction. Also fault codes in IMMO (which Autocom should handle). If there is problem with reading a key then this ECM fault code should not be stored.

Have seen these IMMO modules go bad.
volrem
TwoWaves
TwoWaves
 
Posts: 192
Joined: Fri Jan 03, 2014 5:43 pm
Location: Estonia

Re: Volvo V70 - MY 2000 Immobiliser Fault

Postby STC » Fri Aug 18, 2017 9:22 pm

Hi Volrem

Today it was immobilised again. It fires up and cuts out, eventually just cranks.
I did get Autocom on it tody and found codes in IMMO for Transponder & Key. 720A I believe sets at the same time in PCM. No spare key is avialable so I think I should look at the antenna next.

I took some captures today.
V70 Immo 1.bmp

V70 Immo 2.bmp

V70 Immo 3.bmp
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am


Return to Help me fix my car

Who is online

Users browsing this forum: No registered users and 0 guests