Engine Shuts down and wont start - ECU loosing communication

Engine Shuts down and wont start - ECU loosing communication

Postby Blackbox34 on Tue, 01 Feb 2022 7:47 +0000

Hi,
I'm trying to diagnose a 2014 Hilux with 2TR-FE engine.
The engine just stalled, it would crank but not start again. Disconnecting the battery allowed it to start again.
But the problem keeps re-appearing. The engine will shut down and then will not start again until the negative lead is removed and replaced.
The issue seems to only happen on hot days.

I have downloaded tech stream and the vehicle has 2 active codes.
Immobilizer - B2780 - Push switch/key unlock warning switch. (The wires for the keyswitch in the ignition barrell have been cut to stop the alarm, this code is always active )
ABS/VSC - C1241 - Low battery positive voltage or abnormally high battery positive voltage.
Battery voltage on tech stream reads 13.3V with engine running.'ECU IG power Voltage' reads 'normal'

When the fault has occurred tech stream will not connect to the ECU it says 'Can Bus Check (S604-04)
There is no system found on the communication bus. It will still connect to all other modules.
After the battery lead has been removed and replaced it will find and connect to the Engine ECU again.
Blackbox34
 
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Re: Engine Shuts down and wont start - ECU loosing communica

Postby Blackbox34 on Wed, 09 Feb 2022 5:49 +0000

Bump Bump Any ideas?
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Re: Engine Shuts down and wont start - ECU loosing communica

Postby Gipsy on Thu, 10 Feb 2022 5:19 +0000

Take it to an Auto electrical place or dealer, this is not something you can diagnose through social media ;)
If someone has cut wires to stop the alarm this could be the cause... It's possibly linked to the alarm/immobilizer circuit.
Disconnecting the battery resets everything including codes so that doesn't tell us much.
Cheers Gipsy :D although I'm sure somebody will challenge that :lol: even Einstein wasn't certain of his theories.
My 2013 auto D4D DC SR5, prefilter, 3" exhaust and Chip with egt probe, stock SR5 rims with Toyo Open Country AT2 265/65R/17's
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Re: Engine Shuts down and wont start - ECU loosing communica

Postby Blackbox34 on Fri, 11 Feb 2022 7:10 +0000

Gipsy wrote:Take it to an Auto electrical place or dealer, this is not something you can diagnose through social media ;)
If someone has cut wires to stop the alarm this could be the cause... It's possibly linked to the alarm/immobilizer circuit.
Disconnecting the battery resets everything including codes so that doesn't tell us much.


Thanks, But i am actually a qualified auto electrician and mechanic.
Passenger vehicles aren't my usual industry and im really looking for guidance from somebody familiar with the system and communication network.
The cut wires from the Key alarm are linked to the Immobilizer module- which displays the code B2780. This code is always active and the information on tech stream says it will prevent the car starting. But it does not seem to prevent the car starting as the fault is intermittent but the code is constantly active.

Its not that disconnecting the battery is resetting codes - The ECU module is missing from the network until the battery is disconnected.

The fault seems to correlate with high ambient temperature.
I am going to reconnect the key alarm to eliminate it,
There is also a code related to low battery voltage - although the symptoms do not match in my experience and Techstream displays ECU voltage at 13.3v with engine running.
Blackbox34
 
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Location: NSW Dubbo

Re: Engine Shuts down and wont start - ECU loosing communica

Postby Gipsy on Sat, 12 Feb 2022 6:20 +0000

Ok but you didn't tell us you are a sparkie! Reconnecting the alarm wire is a good start but I still suspect it's to do with the immobiliser circuit. The other possibility you mentioned is abs/TRC, it could be some part of the system which shuts down if a fault is found, I'm sure you would know that codes pending are cumulative and when they reach a threshold a mil is displayed, but in this case the ECU seems to have some bearing on it. That may suggest why it's intermittent? I think black box systems like ECU are far above anyone here so I wouldn't expect too many answers regarding that. ECU voltage may not necessarily reflect the actual voltage at the sensor which shows the fault. There could be a short affecting voltage at the sensor?
Cheers Gipsy :D although I'm sure somebody will challenge that :lol: even Einstein wasn't certain of his theories.
My 2013 auto D4D DC SR5, prefilter, 3" exhaust and Chip with egt probe, stock SR5 rims with Toyo Open Country AT2 265/65R/17's
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Re: Engine Shuts down and wont start - ECU loosing communica

Postby Rob_Wood on Sat, 12 Feb 2022 7:54 +0000

Blackbox34 wrote:
Gipsy wrote:Thanks, But i am actually a qualified auto electrician and mechanic.
Passenger vehicles aren't my usual industry and im really looking for guidance from somebody familiar with the system and communication network.
The cut wires from the Key alarm are linked to the Immobilizer module- which displays the code B2780. This code is always active and the information on tech stream says it will prevent the car starting. But it does not seem to prevent the car starting as the fault is intermittent but the code is constantly active.

XXXXXXX

I am going to reconnect the key alarm to eliminate it,


Maybe try reconnecting ALL the "CUT" wires and then if there's something amongst them you don't want working, then disconnect it again "one thing at a time".
Just a thought.
You should already know this, but try (just to get a base line) to get a Battery voltage with no charge going in, maybe even on a different day.
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Re: Engine Shuts down and wont start - ECU loosing communica

Postby Gipsy on Sun, 13 Feb 2022 8:47 +0000

Here's another possibility, test for codes before the engine shuts down... The ECU must be in the network while the engine is running. Disconnecting the battery zeros the codes but there will be codes pending if you test before the engine shuts down.
Cheers Gipsy :D although I'm sure somebody will challenge that :lol: even Einstein wasn't certain of his theories.
My 2013 auto D4D DC SR5, prefilter, 3" exhaust and Chip with egt probe, stock SR5 rims with Toyo Open Country AT2 265/65R/17's
Gipsy
 
Posts: 2135
Joined: Tue, 07 May 2013 2:00 +0000
Location: South Coast NSW and all over Oz


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