Engine 850: B5234T/2.3/20v/T5: Starting issue

[stuartvolvo]

Hi Pnut. Yes i am still using the original key since i changed the ignition switch

[Jod T5]

Originally Posted by Chris_Rogers

Changing the immobilizer won't help you as it has to be matched to the transponder in the key.

there is no transponder in my key, i am assuming therefore that the receiver i have in my car will not request this information from the key as it is a "basic" alarm and has not been programmed to do so....
as a matter of interest do the master and service keys have transponders in them in the systems that do....
cheers
jod

[stuartvolvo]

Here are a couple of points that i was wondering if somebody could answer.

1. When the engine blew on the car the car sat for 2 - 3 months before being picked up and the battery went flat. Also when the work was being carried out the battery was still flat, until the new engine was put in and it was time to give it a test run. It took several hours to get it to go even with jump leads. Could the imobiliser have lost its memory.

3. From the fault code that i am getting, it looks as if the imobiliser does not recognise the key. what exactly would bring the code up. Is it the antenna not recognising the key or is it something else

4. What is the best route for me to go down now. There is definatley something wrong with the imobiliser. Should i just buy a new one.

5. Is it okay to unplug the imobiliser to check it over and replug it again or will that just upset it?

Regards
Stuart

[Chris_Rogers]

Originally Posted by stuartvolvo

thanks Chris, I now remember that you are correct. The imobiliser has to match with the key.

Here are a couple of points that i would like you to help answer if possible.

1. When the engine blew on the car the car sat for 2 - 3 months before being picked up and the battery went flat. Also when the work was being carried out the battery was still flat, until the new engine was put in and it was time to give it a test run. It took several hours to get it to go even with jump leads.

2. With the car battery being flat for so long could the imobiliser have lost its memory.

3. From the fault code that i am getting, it looks as if the imobiliser does not recognise the key.

4. What is the best route for me to go sown now. There is definatley something wrong with the imobiliser. Should i just buy a new one.

5. Is it okay to unplug the imobiliser to check it over and replug it again or will that just upset it?

Regards
Stuart

The two latest codes you are getting suggest to me that the problem is a lack of response from the key transponder. This could be due to poor connections between the immobilizer and the antenna or the transponder in the key failing, check the connections and try another key this first.
Disconnect the battery first when checking connections to aviod complications.

As far as I remember the car starts OK from a bump start, I think you changed the electrical portion of the ignition switch, but the symptoms point to a poor connection to terminal 15 with the key in the start (III) position.
Have you monitiored terminal 15 at the ignition switch with a voltmeter when the key is in Pos III ?

[stuartvolvo]

Hi chris. Thanks for your reply.
Yes i am getting 12v at terminal 15. i have also tried my spare key, but it does not make any difference. I will try and disconnect the imobiliser and check the wires from there.

Regards
Stuart

[stuartvolvo]

Hi guys. i have also noticed that on the terminal 15 line, there is a overload relay (2/31) on the wiring diagram. Can somebody tell me if this relay is located with the rest of them, next to the fuse box and if it is, what relay is it exactly.

Regards
Stuart

[Chris_Rogers]

Originally Posted by stuartvolvo

Hi guys. i have also noticed that on the terminal 15 line, there is a overload relay (2/31) on the wiring diagram. Can somebody tell me if this relay is located with the rest of them, next to the fuse box and if it is, what relay is it exactly.

Regards
Stuart

Relay 2/31 is relay 106 next to the fuses, access by removing the fuse box cover. IICR this is a 'J' unit ( thermal overload).

[Mark_in_Conwy]

Hi everyone,

I think the relay idea sounds very promising; one of the first things suggested by my volvo specialist was the fuel-pump relay which is a known failure point for these cars. I replaced mine but in my case it made no difference. This was relay 103, the larger square one in the middle nearest the windscreen. I understand that Chris & Stuart are referring to a different relay, number 106, which is one of the smaller square relays next to the fuses, marked "J".

Am I correct, Chris; and if so, do you know which of these 3 "J" relays is number 106? Are all three "J" relays identical parts?

I now have the correct terminal diagrams for the T5 (attached). My apologies that the attachment to my earlier posting (#116) were either for the 2.0 litre 850 or for the 850R.

To avoid any doubt, am I correct to assume that when you are referring to the terminal 15 circuit you are talking about the terminal number 15 in the ECU and that this is the circuit marked 15 on the enclosed terminal diagrams?

Looking through the diagrams, it seems that there are the following relays (amongst others):
- K1 Main relay
- K2 Relief relay 2 for terminal 15
- K3 Electric fuel pump relay
- K5 Relief relay 1 for terminal 15

K4 (fan relay) and K6 (AC relay) also connect through the terminal 15 circuit

My thought is that overheating / intermittent failure of any of these relays might cause disruption to the ECU circuit 15. In my case I have replaced K3 with no effect. Renewing K2 and/or K5 could be a good idea, and if that still donesn't crack it we could try K4 and K6. Any opinions?

Best regards,
Mark

[DLM48]

Originally Posted by stuartvolvo

Here are a couple of points that i was wondering if somebody could answer.

1. When the engine blew on the car the car sat for 2 - 3 months before being picked up and the battery went flat. Also when the work was being carried out the battery was still flat, until the new engine was put in and it was time to give it a test run. It took several hours to get it to go even with jump leads. Could the imobiliser have lost its memory.

3. From the fault code that i am getting, it looks as if the imobiliser does not recognise the key. what exactly would bring the code up. Is it the antenna not recognising the key or is it something else

4. What is the best route for me to go down now. There is definatley something wrong with the imobiliser. Should i just buy a new one.

5. Is it okay to unplug the imobiliser to check it over and replug it again or will that just upset it?

Regards
Stuart

i know this is difficult BUT you are forgetting that the car will start with a push - this means that all your bits and bobs are working fine - and that this problem has 'something to do' with the starter circuit and the activation of the starter motor itself. i do HATE repeating myself - but you NEED to get a scope and start looking at these ECU signals in REAL TIME - EVERYTHING ELSE is CONJECTURE and is only going to drag this out longer frustrate and demoralise you.

[Chris_Rogers]

Originally Posted by Mark_in_Conwy

Hi everyone,

I think the relay idea sounds very promising; one of the first things suggested by my volvo specialist was the fuel-pump relay which is a known failure point for these cars. I replaced mine but in my case it made no difference. This was relay 103, the larger square one in the middle nearest the windscreen. I understand that Chris & Stuart are referring to a different relay, number 106, which is one of the smaller square relays next to the fuses, marked "J".

Am I correct, Chris; and if so, do you know which of these 3 "J" relays is number 106?

It's the middle one


Are all three "J" relays identical parts?


I think so, check the markings on them.



I now have the correct terminal diagrams for the T5 (attached). My apologies that the attachment to my earlier posting (#116) were either for the 2.0 litre 850 or for the 850R.

To avoid any doubt, am I correct to assume that when you are referring to the terminal 15 circuit you are talking about the terminal number 15 in the ECU and that this is the circuit marked 15 on the enclosed terminal diagrams?


No, terminal 15 on the ignition switch, should be live in Positions II & III



Looking through the diagrams, it seems that there are the following relays (amongst others):
- K1 Main relay
- K2 Relief relay 2 for terminal 15
- K3 Electric fuel pump relay
- K5 Relief relay 1 for terminal 15

K4 (fan relay) and K6 (AC relay) also connect through the terminal 15 circuit

My thought is that overheating / intermittent failure of any of these relays might cause disruption to the ECU circuit 15. In my case I have replaced K3 with no effect. Renewing K2 and/or K5 could be a good idea, and if that still donesn't crack it we could try K4 and K6. Any opinions?


I think you are looking at non Volvo diagrams and as such I would not be confident as to their accuracy for all markets.


Best regards,
Mark

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