2006 Aygo 1KR-FE engine cranks but no start!

[Dammizi]

Hi Guys! Im a new member to this forum, hopefully i can get some help with this 2006 Toyota Aygo that does not seem to want to start!

 

Car is:

2006 Toyota Aygo with a 1KR FE engine (3cyl 1.0 petrol), 64,000km

 

Fault: 

Car turns over fine but does not want to fire up (cranking over at approx 300RPM according to my OBD2 diagnostics

Tests carried out so far:

 

Ive downloaded the ecu schematic drawings for wiring pinout,

 

Crank sensor is giving an output according to my obd2 scanner

 

There are no check engine lights on and no faults found on the diagnostic scanner

 

I am getting fuel pressure at the fuel rail ( pump running on ignition on) but coil packs and and injectors ar not getting a trigger signal off the ecu I have checked all supply feeds to the ecu also and it is being fed power with ignition on,

 

I also checked continuity from the crank position sensor wiring up to the ecu

 

Checked also the coil pack plugs, and i get a continuous 12v and ground going to them, but im not sure how to read the trigger signal if there is one coming out of the ecu. 

 

I doubt all 3 coil packs and injectors have fried themselves at once, but none seem to function on cranking over.

 

Does anyone here have experience with a similar fault, and can direct me on what could possibly be keeping the ecu from triggering the coils and injectors from firing?

 

[Dammizi]

This is the schematic i was using to troubleshoot this issue im having.

 

Supply and ground wiring all seems to check out on it. 

 

Am i right in suspecting a dead ecu here? Shouldn't the power supply and crank position sensor feedback be enough to trigger it into firing?

[flash22]

Have you tried the spare key ? Take the AUX belt off and try to start it, what's the voltage of Battery when cranking (read with a meter)

[Dammizi]

I dont have a spare key to it, but im guessing if it is the immobilizer kicking in, it would still start but then cut out after. 

 

Voltage of the Battery is about 11.5 when cranking. I tried using a Battery booster, but it didnt make a difference.

 

I havnt tried taking off the aux belt whilst cranking yet. Could this affect anything to trigger the ecu to fire injectors and coil packs?

[flash22]

ac pumps and alternators can have issues and cause a non start

the immobilizer will cut injectors, spark and fuel pump

Crank and cam sensors will cause a no spark/ no injectors, you will need an oscilloscope to see the waveform, if a cam or crank sensor go out the ecu can calculate a rpm

what are your MAP and CTS readings ?

[Dammizi]

Fuel pump is still running when pressure drops, so only no spark / injectors.

I dont have an oscilloscope, but upon cranking, the revcounter and diagnostics show a cranking rpm of about 300 rpm.

Ill try removing the aux belt, and reading the map and cts readings on monday

Thanks flash!

 

 

 

[Guest]

13 hours ago, Dammizi said:

I dont have a spare key to it, but im guessing if it is the immobilizer kicking in, it would still start but then cut out after. 

I havnt tried taking off the aux belt whilst cranking yet. Could this affect anything to trigger the ecu to fire injectors and coil packs?

On these cars the immobiliser prevents starting so the engine will crank but not start at all.

There's a known problem with the alternator or AC compressor jamming so removing the aux belt removes the risk of this making cranking too slow to allow starting.

[Dammizi]

Hi Dave! Cranking on the engine is approx 300rpm so should be within spec for what is required. Ill anyway try get the aux belt off and give it a go.

 

But cranking speed aside, the car seems to refuse to give out a trigger for the coil packs or injectors to run. So even with the coils out of the engine and spark plugs grounded, there is no evidence of spark being produced.

 

 

How can i know if the immobilizer is not functioning? Can i temporarily disable this to see the engine running? I can see 2 wires from the immobilizer going into the ecu.( Pin 33 and pin 6) are these some canbus data lines or just a 12v/gnd trigger for the ecu?.

 

Also there is no fault on the dash for a key transponder showing. 

[Guest]

10 minutes ago, Dammizi said:

How can i know if the immobilizer is not functioning? Can i temporarily disable this to see the engine running? I can see 2 wires from the immobilizer going into the ecu.( Pin 33 and pin 6) are these some canbus data lines or just a 12v/gnd trigger for the ecu?.

Also there is no fault on the dash for a key transponder showing. 

A few years ago I tried to start with a key without the immobiliser 'chip', there was no indication on the dash of an immobiliser problem.

As to what the connections between the engine ECU & immobiliser ECU are there's no good clue on the wiring diagram other than one has the suffix and the other O - which implies Input & Output but that could be wrong?

[Dammizi]

41 minutes ago, PetrolDave said:

A few years ago I tried to start with a key without the immobiliser 'chip', there was no indication on the dash of an immobiliser problem.

As to what the connections between the engine ECU & immobiliser ECU are there's no good clue on the wiring diagram other than one has the suffix and the other O - which implies Input & Output but that could be wrong?

I have no history of what happened to the car other than servicing it a month or so ago, and came back on a towtruck earlier this week with a no start fault. 

 

Any indication on the chip in the key which i could be looking for? Maybe the owners dropped the key and lost the chip inside? 

We have no spare key for this car and if the immobilizer is kicking in, there seems to be no evidence of it.

Its getting a bit frustrating since im already some 15+ hrs into this job with no clue into solving the issue yet!

Also the pinouts on the ecu are not really well explained so not sure if i can bypass the immobilizer easily!

[flash22]

As i said above, the ecu can generate an rpm with either crank or cam signal missing

go back to basics - and stop over thinking the issue

[Billyboy81]

Have you checked the chip is still inside the key?

[Dammizi]

 

25 minutes ago, flash22 said:

As i said above, the ecu can generate an rpm with either crank or cam signal missing

go back to basics - and stop over thinking the issue

Ok, so with an rpm signal still showing on the diagnostics and on board rev counter the crank/cam signal could still be an issue! So what is the best way of testing them without an oscilloscope? Or do i just go ahead and buy a new set to test out with them?

 

13 minutes ago, Billyboy81 said:

Have you checked the chip is still inside the key?

No i havnt! Is the transponder chip easily visible when opening the key!

 

I really do believe im overthinking this issue 😅 just that im used to immobiliser issues showing up as an engine that starts and cuts off exactly after engine starts running, and seeing an rpm output might be just tricking me into beliving the crank/ cam sensors are ok. 

 

I have tried disconnecting the crank sensor and immediately lost all rpm readings ... 

[flash22]

I would be looking at the Cam sensor then

[Dammizi]

How can i test this cam sensor?

[Dammizi]

Or is it just a case of buying it new and hoping it solves this problem?

[flash22]

Yes, only way to test is looking at the waveform

[Dammizi]

Ok, so big update! Got to the car this morning to check out the immobiliser, seems like the key is empty and missing the immo. Rfid chip!

 

I tried bypassing the immobiliser temporarily by shorting out pins 6 and 33 from the ecu. 

 

The car now starts up immideatley but cuts out after 1 second of running!

I can get a complete ecu with immobiliser and key from a breakers, do i need to fully replace the keyset also or just the rfid chip inside the key + new immobiliser and ecu?

 

Using this idea to try save time and not replace the whole physical lockset on the car.

[flash22]

The key set is just the mechanical key and lock, if you swap the ecu, immobilizer and chip you will need to program the vin into the ecu

you may get away with just a chip and programming it to the car with Techstream as it's an earlier car

random vid off YT

https://www.youtube.com/watch?v=RfON7yVvyjc

Search eBay or the like for a mini-vci

 

[Guest]

3 hours ago, Dammizi said:

Ok, so big update! Got to the car this morning to check out the immobiliser, seems like the key is empty and missing the immo. Rfid chip!

What's the history behind this car? The immo chip is well nestled away inside the key so can't fall out at random so it seems maybe someone deliberately  took it out?

In the UK a good car locksmith can recode the ECU to work with a new RFID chip (using Techstream or a generic tool), do you have equivalent people where you live?

[Dammizi]

Ok guys, so issue was sorted finally!

 

Here is the back story to this issue and how it was sorted.

 

So, apparently the car was parked up and functioned well till the owner went to drive off some time later and it cranked but would not run ( it blew the c/open relay in the fusebox )

The owner thought it was some issue with the key Battery possibly and tried replacing the Battery but dropped the immobilizer chip without noticing. Went back to the car, it still was cranking over but not starting, so he called the towing guys and they dropped it off at my garage .

 

I investigated the ecu not having a supply from ignition and determined it was the c/open relay in the fusebox and got this replaced (complete fusebox from the breakers)

This is when i wrote this post here asking for help! Cause everything else seemed ok now but the ecu would not trigger to start running the engine due to the immobiliser chip missing.

 

Anyway so i contacted the owner agian and he said he still had the chip ( didnt recognise it was essential to the car to run! ), Gotbit back in the key and now it all runs great again!

 

Thanks for all those who helped solve this issue i was overthinking it way tooo much being with it coming in with 2 seperate faults 😅

 

 

[Guest]

On 7/3/2022 at 10:22 AM, Dammizi said:

Maybe the owners dropped the key and lost the chip inside? 

 

14 hours ago, Dammizi said:

The owner thought it was some issue with the key battery possibly and tried replacing the battery but dropped the immobilizer chip without noticing.

Anyway so i contacted the owner agian and he said he still had the chip ( didnt recognise it was essential to the car to run! ), Got it back in the key and now it all runs great again!

Seems you had worked out the problem (missing immobiliser chip) a couple of days ago without being 100% sure!

Glad it's sorted now 👍