RhinoPower Ltd

yknot · Member

RE: Tutorial for the basics of ECU operation-what always works?

TechSupport · Guru

The immo can't easily by disabled it needs modifications to the software which could be quite difficult. Usually with these I reprogramme both the ECU and the immobiliser and then I use a locksmith's tool to match the key(s) to the immo.

yknot · Member

Hello,
I'm new here and i want to know if i can disable immo in a 2002 samurai with g13bb(same as jimny). The car was bought defective(because of the immo) and is stiil in this condition. The ecm can be rewrited to not asking for the immo?
Thank you.

allanapp · Newbie

Hello both. Just wanted to add that I had a very similar fault on my GV2000 here in the Azores - immobiliser had kicked in and both MIL and Immobiliser lights flashing. Engine would turn on the key but not start. Took me ages to resolve the problem but basically the ECU, Immobiliser and key had lost memory and needed reprogramming. Then I still had the Immobiliser problem so with the help of the Vitara manuals I traced the circuits through the ECU and Immobiliser. Main relay and fuel pump were not operating. The problem turned out to be a dry solder joint on the transistor in the ECU that allows the fuel pump and main relay to go to earth. Resoldered, reassembled and since then no more problems! Cheers, Allan

TechSupport · Guru

The factory service manual for the Jimny is available on-line and gives comprehensive fault finding information, try a site like http://www.bigjimny.com for a link to a download.

TechSupport · Guru

By main relay driver I mean the transistor and associated circuitry inside the ECU.

An immobiliser fault usually causes the Check Engine Light or immobiliser light (padlock symbol) to flash. The stock immobiliser unit is usually mounted remotely or is a moulded box fixed above the ignition switch, I haven't seen an LED there. An immobiliser fault should give a fault code starting with 8.

tytower · Newbie

Thanks ,thats a start . I'm assuming the one sensor you refer to is the crankshaft position sensor

Now where might I proceed further in an orderly fashion. Is there a tutorial somewhere .
In my case I appear to have the main relay and fuel pump relay starting up and the check engine light comes on, but does not go out .I appear to be getting a spark at the plugs

I am working on trying your "check engine light explained" tutorial and have printed it out to see if I can get the fault codes out of my ECU. I did not understand what you meant by main relay "driver".

I also have a question on the immobiliser but did not settle on a suitable place to post it yet so I will put it here .
If the immobiliser is not turning off then will the starter motor still turn over. Is there an obvious test to check if the immobiliser is still immobilising the car ?

I notice mine ( a black box tied to the steering column) has a red LED that flashes slowly about once per minute or so . Should that be off? and how do I tell what it is doing?.

So if I catch you in a mood for kindly answering so many laymans questions then thanks in advance

-- Edited by tytower on Tuesday 30th of August 2011 10:25:32 AM

-- Edited by tytower on Tuesday 30th of August 2011 10:27:27 AM

-- Edited by tytower on Tuesday 30th of August 2011 10:28:02 AM

TechSupport · Guru

Nothing can be relied upon to work. If the ECU only has one sensor for engine position then you won't get a spark or fuelling. If the main relay or its driver is faulty then the ECU will not come out of 'sleep' mode.

When testing on the vehicle the first test is does the main relay operate on key on? does the check engine light come on and go off? are there any fault codes stored?

When bench testing I will usually apply power directly and test for serial port communications, that way I know that the processor is 'alive' and I can perform basic checks of the inputs and outputs. Contrary to what you may read elsewhere for most tests you only need a few wires and some basic test equipment to check the primary ECU functions.

tytower · Newbie

May be in wrong section -please move as needed

I would like to know what can be relied on to always work when faced with a car that won't start.

Will the EFI injectors pump in fuel no matter what sensory data is not available ?Will a certain amount of fuel always be released on cranking

Will the distributor always put out a spark as the motor turns over to start? Will some basic settings apply

Will the chip close down completely and refuse to supply sparl or fuel ?

What is a basic starting point?