2004 Rex 300 not starting

[keith pilling]

I have a number of electrical faults on my car. I changed the fuse/module under the left hand side of the dashboard.Now although the car turns over it will not start 

I assume it is the immobiliser that is stopping it 

Does anybody have any idea how to reset it 

 

[Herbie]

Well, with the greatest of respect Keith, just stabbing in the dark and assuming things is not a good way of fixing problems.

Which fuse or module was it that you changed and what circuit(s) does it protect?

It may be the immobiliser but it may not.

Do you have a spark at the plugs?

Do you have fuel to the injectors?

Is the gear selector in P or N as it should be to start the engine? Even if it is, it could be a fault with the starter inhibitor switch that prevents the engine from starting if anything other than P or N is selected.

When you say "I have a number of electrical faults on my car", what exactly do you mean? Start at the beginning and tell us what you've done and why, and maybe we'll have a better chance of helping you mate.

[keith pilling]

Herbie 

thank you for replying this is an ongoing problem i have 

It all started when I was working on my car and I accidentally damaged the main wiring loom going through the bulkhead next to the brake servo.This was repaired but it left me with a number of faults, these included 

air conditioning not working

no display on LCD for a/c or mpg info but showing clock

all warning light showing on dashboard but no gear position PRND no high beam light and no temperature gauge,

all windows work with the switches on their respective doors but not from the drivers door 

the door locking button on the passenger door works but not on the drivers door 

cannot open tailgate from dash button or key fob but releasing it manually from inside boot it relocks itself electrically 

the airbag light on dashboard goes off when started but comes back on

I asked several mechanics their opinions including my local Lexus dealer and not many had any idea apart from in maybe a fuse. I have checked all the fuses i can find and all ok 

i has been to a local electronic specialist but they could not find the fault 

talking to Lexus they said that they would just have to start at the beginning and work their way through which would take time and probably be expensive so I decided to buy a a/c module an the part under the lefthand side of the dashboard which includes several fuses and three bcm’s part number 02731-0w122 just to see if it made a difference 

changing the a/c module made no difference whatsoever 

changing the fuse/bcm module also didn’t work so I changed both these modules back to the original ones and at this time apart from the original faults the car worked 

overnight for some reason the Battery went flat ,i charged it up but found that although the engine turned over it would not fire 

also I found that the key would not lock and unlock the doors so I assume that maybe it was something I did and I have caused the immobiliser to come on 

there maybe Another reason but I’m not sure what 

I have tried resetting the ecu from utube which  involves shorting no4 and 13 on the diagnostic  plug but no difference 

if you or any other Lexus club member have any ideas that I could try firstly to get the car running and maybe some pointers to fixing the rest of my problems it would be appreciated 

 

[Jaystar77]

A damaged wiring loom would explain a lot of that.

How damaged was it and how was it repaired?

[keith pilling]

The damage wasn’t to bad I had only nicked the top of it but it resulted in two wires broken and two just caught the insulation these two were taped and the broken ones soldered back together and taped then the loom was retaped to make good 

[Delphius1]

Cutting and re-connecting two wires doesn't usually result in this sort of catastrophic failure. The only time I've ever seen a list of errors like that is when the Battery has been connected the wrong way round or the car has suffered damage from water ingress.

The only other thing that could explain it is if the wires were something like digital data signal wires where simply resoldering them isn't necessarily the way to repair the wire.

The only thing I can suggest is to hook the car up to techstream so you get an idea of what modules are reporting faults. It's possible that multiple modules have lost connection to a single module and that's why you're getting so many errors.

Have you disconnected the Battery for 20 minutes or so to reset the car's systems? The old "turn it off and back on again!" trick might just reset all the modules so they communicate with each other again.

 

 

[keith pilling]

Have tried disconnecting Battery but it is still the same 

[Herbie]

Wow, I didn't expect an answer like that Keith, that is indeed a catastrophic failure.

I agree with everything Mark said above - it does sound like the Battery or jump leads have been connected the wrong way round or water damage somewhere.

Please don't take offence at this, I'm really not being nasty about it, but it's clear from the way you're just buying and changing things randomly, like the aircon module for instance, you haven't got the skills to tackle a job like this - that way lies an empty bank account and a bald head after pulling your hair out in frustration.

If you really want to carry on with it yourself then starting with Techstream like Mark suggested is a good idea, but I really would strongly suggest that you hand it over to a properly-qualified auto electrician. Not a mechanic or somewhere like Halfords, but a proper auto electrician.

[Jaystar77]

If it were me I'd re-examine the loom, just in case the damage was worse than first thought.  

Just going on your description of what isn't working it sounds like something is shorting out, especially if the Battery is going flat (had the same fun with a parasitic drain on an MR2 years back).  A good auto-spark should be able to trace this by pulling the fuses one by one until the drain disappears.  That might give them a bead on where your fault lies.  

I'm probably off on the wrong tangent and it's nothing to do with wiring!

Keep us posted and good luck with getting it sorted.

[keith pilling]

Thank you for the replies but despite all the problems the car still started and ran and was usable the main problem at the minute is the fact that although it turns over it will not run hence I thought it may be the immobiliser 

the only thing I did was change the two modules but it still ran but didn’t make any difference to the original faults so I put the originals back.Next morning the car had a flat Battery and after charging  the car turned over but would not start 

any ideas why

[Herbie]

You have to be methodical and logical when doing any diagnostics work, let alone such a proliferation of problems, so lets start at the beginning.

1. What were you working on and/or trying to do when you damaged the loom?

2. Do you have a laptop, miniVCI cable and Techstream?

3. If the answer to No. 2 is no, do you at least have some form of OBD2 code reader?

4. Do you have electrical test gear such as a multimeter and clamp ammeter?

If you don't have No.2 (preferably) or No.3, you just aren't going to get anywhere.

If you don't have a multimeter at the very least, you just aren't going to get anywhere.

Here's a couple of pages that give you an indication of what's involved in diagnosing an immobiliser fault:

 

[croxster]

Daft question if it turns over but doesnt start have you tried pressing the fuel cut of switch some times these ACTIVATE when the wiring has been messed with just something to try

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