I connected the jump leads to the wrong ports

  • Thread starter DessyParkerWigWam
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DessyParkerWigWam

DessyParkerWigWam

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38
Location
Wigan
Vehicle
T6 Ocean 150 4Motion
Yes i Know - incredibly stupid mistake!

I now have modules that are not working .. so the AA said - is this fixable? and if so I'm assuming its a very expensive mistake! Has anyone else made such a silly error and what happened?
 
Not sure what you mean by ports?
Do you mean battery terminals?
What happened?
Did something blow?
Have you just checked fuses?
What do you mean by modules?
 
Is the van running? Fingers crossed you’ve not cooked the ecu.
 
Sorry - and thanks for reply - yes meant the battery terminals - ie connected a negative to a positive!

Onr of the eads on the other battery - the one i was using to jump start - started smoking. The AA came out and said there were two unresponsive modeules. (no idea what this meant!). He said he had checked fuses under the passenger seat - but none seem to have blown (he was not very helpful to be honest!)

My worry is i may have caused major damage ..... but not sure if this is necessarily the case
 
Is the van running? Fingers crossed you’ve not cooked the ecu.
What does cooked the ecu mean? and if this is worst case senario - is it fixable?
 
I shoud say - the AA could get the van started with leads - but once turned off t would did not hold any charge
 
Got to be honest, given you are unsure what a cooked ECU means, I'd recommend a trip to the dealer. Going to cost you for the diagnosis though. If you are lucky, it's just blown a fuse that has not been checked properly and/or just damaged the battery, if not, there will be a lot of sensitive components that have been damaged that would be impossible to fault find here.
 
Starting is good / holding charge could be a minor issue like a dead battery.
 
Reverse polarity would fry the alternator surely.
 
I hope the "modules" are the cells within the Battery (A battery is a "pile" of cells, usually 6, hence why older batteries had 6 holes for putting distilled water in). You have buggered your battery for sure!
Connecting a battery the wrong way round normally leads to an explosion so well done!
 
A
Reverse polarity would fry the alternator surely.
Alternators generate ac current which is turned into dc by a diode pack, which should protect against inverse polarity, I'd be more worried about electronics downstream
 
A

Alternators generate ac current which is turned into dc by a diode pack, which should protect against inverse polarity, I'd be more worried about electronics downstream
Thanks for reply - Could I ask what do you mean by electronics downstream? Is that further into the electrical system - If so i assume these are all fixable?
 
I would get a new battery fitted first as that appears to be the first problem.
After that start the engine & see if it will run - sounds like it should if the AA got it running.
After that see if there's any warning lights, or batteries not charging.
You may be fine & its just the battery that's been damaged.
 
So a bit of explanation. A modern vehicle is stuffed full of electronic control units (ECUs). These do lots of different things from controlling the locking/windows (used to be ‘comfort’ ECU in VW speak) to managing braking and stability systems etc. one key ECU manages the engine.

So it is possible that the reverse voltage has damaged or destroyed (cooked) one or more of these ECUs. There is one that manages battery charging for example and I would be surprised if that survived. A diagnostic test is going to be required to see which ECUs respond and which if any seem to be faulty.

The good news however. The engine ECU seems to be functional. The engine starts. Excellent.

So its fingers crossed that the damage is limited to the battery (that is clearly dead) and possibly the battery management ECU. But it needs to be checked out professionally because there may be hidden damage to some wiring.

Good luck.
 
So a bit of explanation. A modern vehicle is stuffed full of electronic control units (ECUs). These do lots of different things from controlling the locking/windows (used to be ‘comfort’ ECU in VW speak) to managing braking and stability systems etc. one key ECU manages the engine.

So it is possible that the reverse voltage has damaged or destroyed (cooked) one or more of these ECUs. There is one that manages battery charging for example and I would be surprised if that survived. A diagnostic test is going to be required to see which ECUs respond and which if any seem to be faulty.

The good news however. The engine ECU seems to be functional. The engine starts. Excellent.

So its fingers crossed that the damage is limited to the battery (that is clearly dead) and possibly the battery management ECU. But it needs to be checked out professionally because there may be hidden damage to some wiring.

Good luck.
Thanks for explanation - that is really helpful especially for someone like me who has no understanding of engines and electrics.

I've managed to get it booked into a garage - and encouragingly (I think) it did start straight away - despite it being 2 days since the AA got it started on my drive. This meant that I could drive it to the garage without problem - just the red battery light was on and no yellow/orange warning lights! Be interesting to see what garage finds with diagnostics - I'm hopeful but worried : )
 
Thanks for explanation - that is really helpful especially for someone like me who has no understanding of engines and electrics.

I've managed to get it booked into a garage - and encouragingly (I think) it did start straight away - despite it being 2 days since the AA got it started on my drive. This meant that I could drive it to the garage without problem - just the red battery light was on and no yellow/orange warning lights! Be interesting to see what garage finds with diagnostics - I'm hopeful but worried : )
That's very encouraging. I should have asked - what was it you connected to? A battery charger? Normally they have reverse polarity protection (i.e. wont switch on if connected wrong) so that's a bit strange. If you had connected to another battery however I would have expected a big bang - and vaporised charging leads! If it was a battery charger you used then I would guess potential damage is pretty limited. The charger will have given up before the Cali!
 
That's very encouraging. I should have asked - what was it you connected to? A battery charger? Normally they have reverse polarity protection (i.e. wont switch on if connected wrong) so that's a bit strange. If you had connected to another battery however I would have expected a big bang - and vaporised charging leads! If it was a battery charger you used then I would guess potential damage is pretty limited. The charger will have given up before the Cali!
I plugged it into my other car ! On one lead where connected to my other car - the lead started smoking on my other cars battery and the plastic on the lead at that battery point melted - but no bang!
 
I plugged it into my other car ! On one lead where connected to my other car - the lead started smoking on my other cars battery and the plastic on the lead at that battery point melted - but no bang!
Wow - Well by far the most important thing here is that you were not hurt. What you describe is pretty dangerous and unpredictable (depending on the relative state of the two batteries etc.).

The battery with the higher voltage (in your case the car) will force current (a lot!) through the battery with lower voltage (your Cali). The current flow can be very large and hence wire melting, fire causing etc. The battery that is forced into reverse voltage will be destroyed pretty quickly - that you know to be the case!

Thereafter it is a question of how the systems attached to the Cali battery react when they see a negative instead of positive voltage. Sensitive electronics are typically destroyed by reverse voltages BUT there are two mitigating factors (i) because your Cali battery was not at zero volts to start with it (and hopefully not far off the voltage of the car battery) will mean that the negative voltage delivered to the system is going to be small. (ii) those sensitive electronics will have some inbuilt protection against negative voltage inputs.

So if the engine ECU is anything to go by you are OK. The other likely collateral damage is the alternator, which being hard wired to the battery may not have taken well to a negative voltage.

But as I started - the most important thing is you escaped without injury. The bits of copper and silicon be replaced!.
 
Sorry - and thanks for reply - yes meant the battery terminals - ie connected a negative to a positive!

Onr of the eads on the other battery - the one i was using to jump start - started smoking. The AA came out and said there were two unresponsive modeules. (no idea what this meant!). He said he had checked fuses under the passenger seat - but none seem to have blown (he was not very helpful to be honest!)

My worry is i may have caused major damage ..... but not sure if this is necessarily the case
Ask AA to send a VW tech. Insist on a VW tech only. They will be more helpful and also help you to understand what's wrong and also the solution.

Sent from my Pixel 6 Pro using Tapatalk
 
Ask AA to send a VW tech. Insist on a VW tech only. They will be more helpful and also help you to understand what's wrong and also the solution.

Sent from my Pixel 6 Pro using Tapatalk
If it’s Purely a new battery required the AA / VW assist will sell you a new battery , fit it and code it , then check the vehicle for any other issues.
 
I did this many years ago on a diesel generator.
It burned out the engine alternator. Probably the diodes.
After fitting a new alternator everything worked perfectly.

Presumably the van battery was low, resulting in the need for a jumpstart.
There is probably enough charge in the battery to allow the engine to run after a new jumpstart, but the battery is not charging due to the dead alternator.

Check the battery terminal voltage when the engine is running.
It should be about 13 or 14 volts if the alternator is working.

If it's less that this, try charging the battery using a mains charger. If the battery charges it's okay.
 
Thanks for explanation - that is really helpful especially for someone like me who has no understanding of engines and electrics.

I've managed to get it booked into a garage - and encouragingly (I think) it did start straight away - despite it being 2 days since the AA got it started on my drive. This meant that I could drive it to the garage without problem - just the red battery light was on and no yellow/orange warning lights! Be interesting to see what garage finds with diagnostics - I'm hopeful but worried : )
To me the fact it started 2 days after AA attended suggests
1) The engine battery had enough charge to sustain power to engine ecu, close relays to allow starter solenoid to engage and draw enough current to spin the engine.
So a battery test will reveal extent of damage although in all probability it may not be salvageable.
2) The other concern is with the engine running the battery light is on suggesting damage to alternator and systems monitoring battery health and charging management.
This needs vehicle electrician to diagnose
a) Wrecked alternator?
b)Battery charge monitoring Control Unit functioning
C) Vehicle start stop system which relies on the above to operate.
 
To me the fact it started 2 days after AA attended suggests
1) The engine battery had enough charge to sustain power to engine ecu, close relays to allow starter solenoid to engage and draw enough current to spin the engine.
So a battery test will reveal extent of damage although in all probability it may not be salvageable.
2) The other concern is with the engine running the battery light is on suggesting damage to alternator and systems monitoring battery health and charging management.
This needs vehicle electrician to diagnose
a) Wrecked alternator?
b)Battery charge monitoring Control Unit functioning
C) Vehicle start stop system which relies on the above to operate.
Before replacing the Alternator, check the Lin connection from battery to alternator, it’s a thin cable that monitors output of alternator vs battery voltage (the smart charging sensor) any damage to that cable will throw an alternator light.

Easy cheap fix to check up before an expensive Alternator replacement.

Start with battery and work backwards
 
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Before replacing the whole Alternator, check the Lin connection from battery to alternator, it’s a thin cable that monitors output of alternator vs battery voltage (the smart charging sensor) any damage to that cable will throw an alternator light.

Easy cheap fix to check up before an expensive Alternator replacement.

Start with battery and work backwards
Great advice thanks. Ive got my van into a local garage and I have mentioned this to him - hopefully get a full diagnosis today...... I think it will be expensive
 

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