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Discussion Starter · #1 ·
Hi I am a newbie to Volvo V40 and this forum
I have a issue with my reverse lights on a 2014 Volvo v40 d2 deisel 1.6 with a manaul transmission, I have had the lights staying on after reversing in forward gears,1st gear light on dash staying on in reverse with no reverse lights and reverse lights not working when in reverse.

Could anyone tell me where the gear position switch is located please ????
 

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Discussion Starter · #3 ·
I recall reading a post a while ago, hopefully assists...

Neutral Position Sensor Location? | Volvo V40 Forums (volvov40club.com)
Thank you very much for enlighting me, I think you are on the right track here as my stop/start is not working as it should,( has not concerned me as I prefer it not stopping and starting in traffic), this maybe is why my reverse lights are random.

Would this mean I need to visit a dealer for them to investigate :( or would I be able to test it further myself as do have a electical background but I would need a scanner to read codes and clear them if one is available to purchase.

Thanks again
Peter
 

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You need to be careful about failures in such switches. Usually, though I don't know the specific setup on a V40, such sensors are used to inhibit the starter, so that you can't start the car in gear. So a developing failure could leave you immobile. Manual versions will also have a sensor on the clutch pedal.
(My non-Volvo had exactly such a problem, luckily it's a bit older and the faulty switch/sensor can easily be bypassed by shorting out a relay until it's properly fixed. More recent electronics might not be so amenable)
 

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Discussion Starter · #5 ·
You need to be careful about failures in such switches. Usually, though I don't know the specific setup on a V40, such sensors are used to inhibit the starter, so that you can't start the car in gear. So a developing failure could leave you immobile. Manual versions will also have a sensor on the clutch pedal.
(My non-Volvo had exactly such a problem, luckily it's a bit older and the faulty switch/sensor can easily be bypassed by shorting out a relay until it's properly fixed. More recent electronics might not be so amenable)
Thanks I am aware that you can easily damage a control module by making a incorrect connection to the wiring and most newer models do have this twisted wire coms between the modules within a car.
 

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Discussion Starter · #7 ·
on the subject of scanning, sometimes its ok to use a cheap code reader, but I had endless problems diagnosing an older C30 even with a "snap-on" item, only the Volvo tool fetched the correct fault code
Thanks that doesnt surprise me really :( I contacted my local dealer today for them to do a check to see if any outstanding recall action were outstanding on my car and was given the all clear :) couldnt resist asking what they charge hourly for a visit to their workshop it is currently £144 inclusive of VAT :(
 

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Discussion Starter · #9 ·
Id be finding a local independent specialist for that job
Correct, I will have to find one with good reviews and ask if they have volvo dealer equipment at hand for dianostics.
Thanks for you help so far (y) I will have a look for that selector sensor you mentioned and check connections are good also try disconnecting batteries to force a hard reset first.
Regards Peter
 

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also try disconnecting batteries to force a hard reset first.
Great idea
Our friends at Vauxhall condemned my old Vectra with an EML on, was driving fine (as well as a vectra would) , Their diag "Tech2" system couldnt access the ECU and they asked me for almost a grand for a new ECU to put it right. I said no, and thought time had come to put it through an auction. That night, battery off, in the garage and on charge. Ran perfect the next morning.
 

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Discussion Starter · #11 ·
Great idea
Our friends at Vauxhall condemned my old Vectra with an EML on, was driving fine (as well as a vectra would) , Their diag "Tech2" system couldnt access the ECU and they asked me for almost a grand for a new ECU to put it right. I said no, and thought time had come to put it through an auction. That night, battery off, in the garage and on charge. Ran perfect the next morning.
Do you know its not even easy to disconnect the power supply from the car as it has 2 batteries one of which is hidden behind the front bumper that you would need to removed to get to the connections.

Is there a better and easier way to disconnect power from this battery without removing the bumper to remove its power from the cars electical system I am wondering ??
 

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Do you know its not even easy to disconnect the power supply from the car as it has 2 batteries one of which is hidden behind the front bumper that you would need to removed to get to the connections.

Is there a better and easier way to disconnect power from this battery without removing the bumper to remove its power from the cars electical system I am wondering ??
Disconnecting the main battery completely isolates the batteries from the vehicle under all normal circumstances. The secondary battery is connected through a relay controlled by the CEM, which only closes on a start request from the start/stop system, to momentarily power all running consumers so that the main battery is dedicated solely to operation of the starter motor. The circuit remains activated after a restart for however long it takes the alternator to recharge the support battery. With a support battery in good serviceable condition, recharge time averages about 5 seconds, following which the relay will open, again isolating the secondary battery until required to support the next start/stop restart. At all other times the support battery is isolated from the vehicle, so it should only be a concern if you intend to work on the electrical system whilst the car is starting from a start/stop event or for a few seconds thereafter, unless there is a fault in the support battery relay, which would be communicated through the DIM.
 

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Discussion Starter · #13 ·
Thank you for explaining that to me, the reason why I asked this when I disconnected main battery to recharge and test it on reconnection I expected to reset clock and window settings but found this didn't need doing 🤔.

I did check for a voltage reading on main battery lugs while battery was disconnected it was reading 1.04 volts which maybe would be enough to keep control modules in retain their values.

Would there be a way of disconnecting, recharging, testing the secondary battery other than removing the front bumper off the car.
 

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Discussion Starter · #16 ·
Just a update to let you know what i have found so far, the reverse light switch was removed and tested appears to work as it should but reverse lamps still inoperative :(

I had a 3 hour journey in the car the other day and then found the stop/start and reverse lights all worked fine and majority of the time still is now :unsure:,

I am now thinking this could be battery related, awaiting a agm battery tester to arrive for me to do a test on the main battery.
 
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