Stop light on dash engine won't crank !!!

[vernon]

Lingo 2007 1.6 hdi
Stop light on dash engine won't crank
Will start ok with a bump runs fine with no eml light showing The only codes that came up pending were 1351 glow pug relay & 0704 clutch switch no signal or incoherent 
I have tried the starter motor whilst the engine is running that OK.
I have cleared the fault codes turned the key no glow light and stop light on.
When I turn the key to the cranking position stop light goes out and I here 1 click from the fuse box under dash (drives side) engine does not turn over. when I release the key the stop light is back on. am really stuck now as I work away and the wife needs the car to visit here patients.

Could this be a BCM fault    Hope not

[3rensho]

What is the battery voltage with motor off and running?

[vernon]

What is the battery voltage with motor off and running?

At rest bat voltage 12.8 running 13.4 volt

[3rensho]

From other posts I've read the voltage when running should be over 14 volts - 14.2 to 14.4. I'd get the battery checked and also look for loose or corroded connections.

[vernon]

From other posts I've read the voltage when running should be over 14 volts - 14.2 to 14.4.  I'd get the battery checked and also look for loose or corroded connections.

i have disconnected the existing battery and connected a very large jump battery and still the same symptoms.

[jj9]

So it's not a battery problem then.

I don't think the codes (1351 & 0704) are anything to worry about as I've read of others having these codes but their car still starts and goes as normal.

So where does that leave you, I think I would be investigating the 1 click you here from the fuse box, maybe that can throw some light on the problem.


.

[Gravity]

I have disconnected the existing battery and connected a very large jump battery and still the same symptoms.

Whatever battery you connect, if there is a corroded terminal elsewhere - say at the starter motor itself - the same problem you're having will remain. A different battery will not magically cure a problem elsewhere, so it will pay you to check other areas, as jj9 suggests - possibly starter motor connections.

The 'running' voltage seems low. If you increase the engine speed to, say, 2000 plus rpm for several minutes, then take a voltage reading, that would be more accurate. It should read well over 14 volts - say, 14.6 volts. If it doesn't, that suggests an alternator below par.

Gravity

[jj9]

I ruled out the starter motor connections as he said once the engine was running via a bump start the starter worked ok, but it would be sensible to check the connections were in good clean condition.  



.

[vernon]

jj9I ruled out the starter motor connections as he said once the engine was running via a bump start the starter worked ok, but it would be sensible to check the connections were in good clean condition.  


Battery voltage is now showing 14.2v   (Previous check on cheep un calibrated meter)
I have had her connected up in the snap on versus. No fault codes showing scoped all possible set points. All spot on no dramatic variations that would cause the stop light & non cranking.
There is no signal from the ECU to the trigger wire on the starter as I expected. 
The starter motor is fine as I diconnected the trigger wire and connected a fused 12v Suply.
With the ignition on with the stop light on I can remote start the engin with a momentary switch.
 I am now at the chicken and egg stage. I am still no wiser as to why there is no signal voltage.
There is something in the ECU I presume that is triggering the stop light that is intern not letting the engine crank. 
I bit more head scratching & tea & manual reading to understand how to operate the versus to be able to reprogram a second ECU just in cases. I have found a used but working ECU that's free.
Any advice before I delve into the point of no return of ECU cloning

[jj9]

You're going to need someone who knows the ECU and how exactly the system operates. 


.