Help yaris won't start!

[shaunsm_uk]

Hi all,

Hooefully someone can help, my other halfs 2002 yaris won't start after being parked for the weekend, it was running perfectly before, it cranks over no problem and have taken the plugs out and there's definitely fuel but no spark on all coils, I've checked all fuses and even swapped the EFI relay, there are no ECU codes showing up,

Not really sure what to try next, could it be the crank sensor, I don't want to go swapping parts as it could get expensive but without codes showing up I'm a bit at a loss, could a sensor go without showing a code?

Thanks in advance!

[YarisSedan]

How did you determine there is no spark and that there is fuel. If it was a crank sensor it would not have either.

[shaunsm_uk]

I've taken a plug out, grounded it cranked it over and no spark as mentioned tried this on all four coils, it definitely getting fuel as plugs wet with petrol, wouldn't be able to tell fuel pressure without testing kit but no spark is a bit of a give away

[CTScott]

Check the AM2 fuse in the under-hood fuse panel. Also check with the ignition switch in the ON position for the presence of 12 Volts on brown wire on the first coil connector. If the AM2 fuse is good, but you don't have power on the brown wire, then the IG2 relay within the Integration Relay assembly is bad. The Integration Relay assembly is a block in the under-hood fuse panel.

[YarisSedan]

Not sure exactly where the fuel test port is on the yaris. If you have the engine cover off already on the fuel rail there should be a little plastic cap if you unscrew it you should see the valve. Take a pen or small screw driver and depress it with the key on and see if fuel squirts out. If not have someone trying to crank the car while you press on it and see if fuel comes out.

[CTScott]

Not sure exactly where the fuel test port is on the yaris. If you have the engine cover off already on the fuel rail there should be a little plastic cap if you unscrew it you should see the valve. Take a pen or small screw driver and depress it with the key on and see if fuel squirts out. If not have someone trying to crank the car while you press on it and see if fuel comes out.

The Yaris does not have fuel test port. Toyota techs have a SST kit that contains a T fitting that connects in between where the fuel rail meets the fuel line.

[YarisSedan]

The Yaris does not have fuel test port. Toyota techs have a SST kit that contains a T fitting that connects in between where the fuel rail meets the fuel line.

Ahh okay, I've worked on a lot of cars but never the yaris seems to be a bullet proof car.

[shaunsm_uk]

Thanks for all the suggestions, I'll check tonight when I get home, I did have a look for a fuel test port but couldn't see one, I have a feeling it might be the relay CTScott suggested as I've checked all the fuses, will let you know what I find :-)

[shaunsm_uk]

Hi all,
Ok so I've tried to get voltage off the coils, I could only get a 5v reading off the 3rd wire along from the left of each coil with ignition on, couldn't find what CT described as the IG2 relay under the hood but one marked EFI (uk car so may be different) I've tested every relay individually and all look healthy, make contact etc, starting to run out of options,
Ive tried some easy start sprayed into the intake which should have kicked it into life if it was a fuelling issue, but still no sign of spark.
Just a random question but could it be the immobiliser? (I've also tried the spare key)
I'm still leaning towards crank sensor as surely this tells the ECU when to fire and what position?
Does the engine have an ground/neutral strap as couldn't find one
Am sure I've got more grey in the last few days ;-)

[CTScott]

With the immobilizer the ECM won't fire the injectors, so your plugs would be dry.

The integration relay, which includes the IG2 relay is this piece:
50429

If you release the clips on the end of it you can pull it up to see its bottom connectors:
50430

The 12V measurement (with the ignition switch in the ON position):
50431

The 5V that you are seeing on the pin next to the 12V pin (5 volts is logic from the ECM and 12 volts is the power feed for being able to fire the coils):
50432

[shaunsm_uk]

Just double checked the voltages on the coils and can see 12v on the one you show as brown and 5v on the next along same as yours but wires are different colours, it raining now so didn't want to hang around too long! Here's a pic of the relay/fuse box under the hood, argh getting sense of humour failure

[CTScott]

Just double checked the voltages on the coils and can see 12v on the one you show as brown and 5v on the next along same as yours but wires are different colours, it raining now so didn't want to hang around too long! Here's a pic of the relay/fuse box under the hood, argh getting sense of humour failure

I just noticed that you said it is a 2002. I was thinking that it was a 2nd generation. Let me check the difference for the 1st generation and I will get back to you...

[CTScott]

OK - 1st gen is even more simple. There is no relay in circuit. The AM2 fuse supplies 12 volts through the ignition switch to the same wire as I indicated on the coils.

The power comes into the ignition switch on a white wire with a red stripe and leaves the switch (headed to the coils) on a brown wire with a red stripe.

If the AM2 fuse is good, I would check the voltage on those two wires on the ignition switch.

[shaunsm_uk]

Hmmm could it be the ignition switch, do you have a wiring diagram or pinouts for them?

[CTScott]

Hmmm could it be the ignition switch, do you have a wiring diagram or pinouts for them?

Yes. That's where those wire colors I mentioned to check come from. Those two wires are all that goes through the ignition switch that is related to the coils.

[shaunsm_uk]

Just checked the ignition switch as the attached pic, the thinner wires on the right of the connector white/brown is the 12v feed, with ignition on the black/red wire has 12v and on trying to start the black wire also gets 12v
On the left side of the connector thicker wires 12v feed comes in on the white/blue opposite the thinner black cable, and the other two get 12v when switch is turned to on position, so I'm pretty confident the ignition switch is ok?
Where do I go from here :iono:

[shaunsm_uk]

Also forgot to mention the security/immobiliser light goes off when key is in ignition so don't think it's the immobiliser doing anything odd

[CTScott]

After seeing that the 12V is present after the key switch, did you go back and check the coil connectors again?

If you still don't see 12V on the coil connector, then the next thing would be to check the wiring between the key switch and the coil. There is a junction connector EC1 that it routes through. That connector is the one in your fuse box picture. The wire in there is still black with a red stripe. Check the voltage on that wire, with the ignition switch "ON".

[shaunsm_uk]

Solved! :headbang:

After going back and double checking everything,this time in daylight and still no luck I connected up a battery from another car and hey presto! I got spark! Really annoying as I had even jumped from the same car to the yaris without any luck, put everything together and installed a new battery and fires right up, just goes to show you never over look the simple things! Well I hope it was that and not a loose connection anywhere :-) time will tell.

Thanks CT for all your help, you really where. Great help in figuring this one out and thanks for your time, fingers and eyes crossed its all ok now!:bow: