96 D1 check engine light mystery.

[1996trek4]

Check engine light
will fail to illuminate with the other warning lamps with ignition on
intermittently. When this happens, the truck will crank but will not start. When
the check engine light does come on with the ignition, all is fine. I need to
find out what specifically controls the check engine light separate from the
bulb check relay that turns them all on with ignition initially in order to
track this down. It will be fine for a week or two and then out of the blue-act
up... I already put in a new CPS thinking that was the most likely culprit and
it obviously is not. No wiring diagrams exist on RAVE or in the factory shop
manual I have for some stupid reason. Relays all look good in the right kick
panel although I think most are body related. ECU is dry and plugs look clean.
There are some plugs behind the washer reservoir from the ECU I have not checked
as I do not know which one would be the right one, but expect them to look the
same as the others...

Does the ignition
switch give a signal to the ECM that may be getting interrupted? Not sure if the
ECM gets a ignition on signal and then controls the check engine light coming on
if it gets this signal. No idea what wires to check or what to look for since no
one has a wiring diagram....

[giftshopduane]

Send ma a fax number (I can't save it as a PDF..) and I'll send the Diagram.

chris@kaizentuningdotcom

[giftshopduane]

Actually hang on... PDF in process.

[1996trek4]

c_prowse2001@yahoo.com is my email..... I looked into the wet ecu thing some talk about. My 98 has never given me trouble and the cover just snaps over against the inner fender-no seal of any kind...96 is the same and it did it to me the first time at the end of a dry week so everything should have been bone dry. It's not a daily and not even licensed yet because when I took it in to get emission tested, they shut it off and it would not start, in an hour of playing with it, light came on and it started and I took it home... Was fine for a week and then did it again... A few turns of the key does not make the light come on, it may be dead for a week or better before the light decides it want to work, then be fine for another week or so...

[giftshopduane]

File sent....good luck.

[1996trek4]

Well, it looks like the check engine light gets power with all the other warning lights through the same fuse and bulb check relay. The signal comes from the ECM and alarm module. Since my alarm and keyless entry works, odds are it is my ECM. Now what I need to find out is if the starter can crank without the ECM, if it does, the ECM may not be getting a ignition on signal from the ignition. If the ECM is not powered up, it can't very easily turn the check engine light on. Otherwise, it may be the ECM itself. I know the ECM controls spark and a host of other management systems. What I do not know is how it interacts with everything. Also need to find out if I can swap the ECM from my 98 as a test. Some say you can not without pairing it at a dealer and will not work once put back in my 98 either. Others say it is not a problem.... If I can, it would tell me if I am chasing an ignition problem or an ECM problem... Not doing it until I know for sure....

[mearstrae]

It may be a "Dis-abler" problem, that is the alarm system gets a signal that it is being stolen and disables the ignition or fuel pump (I don't remember which/or both) and a falure to start happens. A friend of mine had this problem and used to cycle his door locks and then start the thing right up. (Gotta love Land Rover electrical logic...) I don't know if this is it, but it's worth a try.

'95 R.R.C. Lwb
'76 Series III Hybrid 109
'70 Rover 3500S

[1996trek4]

Does the alarm issue cause the check engine light not to come on? The no start is lack of spark and it only does this if the check engine light does not come on with the ignition. If the check engine light does come on with ignition it fires right up... No one anywhere has been able to tell me what causes the check engine light not to come on. I am sure someone somewhere has had this happen and figured it out.

[mearstrae]

I also never heard of this particular (peculiar...) problem and don't know how the Check Engine Light affects the starting. I thought it was just a warning that a sensor was showing an error somewhere in the system (or usually a failed sensor itself). My '95 Check Engine Light seems to go on and off at its own whim, so I pretty much ignore it.

'95 R.R.C. Lwb
'76 Series III Hybrid 109
'70 Rover 3500S

[mearstrae]

I had to dig this out of the archieves...If you can't laugh about these Land Rovers you're going to cry...

'95 R.R.C. Lwb
'76 Series III Hybrid 109
'70 Rover 3500S

[1996trek4]

The check engine light is supposed to come on with the other warning lamps when the ignition is first turned on, then go out in a few seconds or when the engine starts. Coming on or off when running is normal if there are faults. If the check engine light fails to illuminate with the bulb check it will not allow the truck to start (verified no spark)...Alarm and keyless entry work as normal. There are differences between your 95 and my 96 "GEMS" and if it is NAS or ROW build... It is driving me nuts and I may have to throw it on the trailer and take it down to the stealership to get an answer....