Water leak causing power failure

[James]

Hello

my 2004 2.4 hybrid Alphard has spent the last 9 months in and out of the garage suffering loss of power. It doesn’t start as seems not to recognise the hybrid battery. The garage have checked out the battery and cleaned up contacts etc and give it back to me ‘working’ only for me to do 5 miles and the same problem recurs! 
it first failed on a wet day, the second was after returning and I found the drivers footwell carpet sodden beneath a dry footmat, the third time I had tested to see if the moon roof and sunroof drains were blocked (they were clear, water running out at the wheel arch areas), the next was after washing the car and the last time was after spraying a hose over the car to see if the problem would recur which it did after about 5 minutes after the hosing.

the next day the car started and ran again.

i have currently masking taped the moon roof and sun roof and it has started after a light shower.

Is it possible to access the roof drains along their length to see if there is a leak and what it may be shorting? Any suggestions as to where the problem may be?

could it be water getting under the bonnet into the engine compartment from the windscreen base drain and running onto the hybrid unit front right?

sorry it’s a very long post but really stuck and can’t use the car if it is unreliable. Have lost confidence in the garage having spent a lot of time and money to have a car back with the original problem!

thanks for your help guys!

[Picasso]

hello james sorry your having bad look at the moment have you tried have a smoke test not sure if thats what its called in the car see if there is any places where it might seep out of the sealed vehicle .

[James]

Hello Picasso

no I haven’t heard of it. I will look it up thanks.

[Jeza]

The inverter/converter is very well sealed as is the battery. I would look at this as two separate issues to start with. Do you get any warning lights come on? Is the 12v aux battery good, full capacity and holding charge? When trying to start can you hear the Hybrid relays click from under the passenger seat? Have you checked for any jobd fault codes? Low power could be the engine or the Hybrid system sensing an issue and going into safe or limp mode, engine revs more especially at low speeds. I presume the water leak clear water and not coolant!

[James]

Hello Jeza

Thanks for your help.

the attached are what the dash shows. Yes you can hear the clicking relays when it is trying to start. I think the ecu is detecting a problem and going into safe mode. I assume something is getting wet and drying as eventually restarts and runs fine. 
I retested roof drain and traced it down on drivers from side and all seemed fine yesterday and started after test. Even started after overnight rain. I checked panel welds under roof sealing strips and they are all clean and intact.
not sure about colour of fluid. I think clear and doesn’t smell of coolant.

the 12v battery was replaced a couple of months ago and is fine. When problem occurs it will not start even after battery disconnection and on mains charger/ starter.

dont have fault codes to hand but will get them and post them.

appreciate your help and suggestions. J

[James]

Thanks to Picasso too. I had not heard of smoke test so will look into it.

[Shaggy]

Hi there just wondered if you have checked under the silver plastic cover on the right hand side of the engine compartment? THS-C is written on it.

Pull it up from the front and lift out.

Underneath is a series of electrical wiring connectors you may have some water/moisture contamination? Give them a spray of WD40 it might help?

[James]

Thanks Shaggy I will give it a go.

 

[smurf]

Leaks from the windscreen seal are not uncommon. 

[James]

Thanks Smurf 

[Jeza]

C1213 - The skid control computer communicates with the hybrid control computer and controls the braking force in coordination with the motor regenerative operation.

Reception or transmission to or from the hybrid control computer is not possible. Check the sub code on the data page, could be 152, 153 or 154. 

This is not necessary a fault, if there is an issue with the hybrid system it stops talking to the other systems.

 

P1636/81 When communication from the Engine Control Computer with the hybrid vehicle control computer is lost

Possible issues - Wire Harness or Connector or computers

 

P3002 - When an error occurs in communication from the hybrid vehicle computer to the battery computer ASSY

Wire Harness or Connector

Hybrid Vehicle Computer

Battery computer assembly

 

As the hybrid computer seems to be the common issue I would check all the connectors and harnesses on both the ECU, hybrid computer and battery ECU for damage and water ingress. ECU's are located behind the passenger stowage box and the battery ECU under the passenger seat, connector accessible behind forward trim.

 

I can give you the connectors and relevant pins to check for continuity of each harness.

 

Interestingly on P3002 fault diagnosis the first check is to "Stop operation of all aftermarket vehicle products or electrical products brought into the vehicle." then check if the fault code reappears. attached images are for P3002.

[James]

Thank you Jeza that is very helpful.

at the moment, amazingly, despite the rain the car has been running normally! Carpets dry and no obvious water ingress! 
I found the positive connector was loose when it failed (something I wasn’t expecting as it was newly back from the garage). 
Will keep my fingers crossed it keeps going.

Really appreciate everyone’s help. Thanks