Toyota Yaris - Toyota Yaris Engine Light Stretched Timing Chain

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Sun 21 Feb 2016 20:55
Toyota Yaris - Toyota Yaris Engine Light Stretched Timing Chain - Rih26
Had to jump start my 2005 Yaris yesterday as the interior light was left on. The orange engine light popped up on the dash, I was already on the way to the mechanic to grease my brakes. He ran a diagnosis on the car and the code read stretched timing chain. Now my understanding is that it's pretty rare for this to happen, but if the chain snaps I'm in for a huge bill! So I'm wondering, would jump starting the car cause the computer to go a bit mad and throw this code up? Or is it likely the chain really has stretched even though the car has only done 56k?!
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Sun 21 Feb 2016 22:18
Toyota Yaris - Toyota Yaris Engine Light Stretched Timing Chain - Railroad.
The ECM cannot know if the timing chain has stretched, but it will know if the synchronisation between the crankshaft sensor and the camshaft sensor is outside its limits. And the most obvious reason for this is a timing chain fault. Not enough to cause damage, or to prevent the engine running, but you should take this seriously before something worse happens.
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Sun 21 Feb 2016 22:24
Toyota Yaris - Toyota Yaris Engine Light Stretched Timing Chain - Rih26
Thanks for your reply. I'm thinking of taking it to Toyota, letting them run another diagnosis and taking it from there? Someone has said to me that jump starting can cause the computer to do weird things because of the low voltage going through the battery. I just don't want to cause any damage or breakdown.... I drive alone with my 2 small children a lot so I'm now worried about driving! The mechanic reset the light and basically said it's not worth fixing so he wasn't very helpful or reassuring!
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Mon 22 Feb 2016 10:05
Toyota Yaris - Toyota Yaris Engine Light Stretched Timing Chain - Railroad.
Connect a vacuum gauge to the inlet manifold. Start the engine and allow iit to idle. The vacuum reading should be a steady 21in/hg or near to it. A steady reading lower than that would indicate late valve timing.
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Mon 22 Feb 2016 10:10
Toyota Yaris - Toyota Yaris Engine Light Stretched Timing Chain - Wackyracer

If you can find a very helpful diagnostic person, they will be able to compare the camshaft sensor signal to the crankshaft sensor signal to see if there is a discrepancy in the timing using a dual channel scope.

The problem with electronics on cars is, most garages just don't have a clue how to diagnose faults using these systems.

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Mon 22 Feb 2016 11:17
Toyota Yaris - Toyota Yaris Engine Light Stretched Timing Chain - Railroad.
And in addition to the above post many garage mechanics will plug in the diagnostic equipment and read fault codes which says this sensor or that sensor, and fail to see any further than a faulty sensor. Completely forgetting that the sensor is there to monitor and provide information to the ECM.
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Mon 22 Feb 2016 12:12
Toyota Yaris - Toyota Yaris Engine Light Stretched Timing Chain - John F
I just don't want to cause any damage or breakdown.... I drive alone with my 2 small children a lot so I'm now worried about driving! The mechanic reset the light and basically said it's not worth fixing so he wasn't very helpful or reassuring!

You won't. Don't worry. The chain is like a bicycle chain, they hardly ever suddenly snap despite the rare horror stories on line. It might rattle a bit if it's high mileage. Sounds as though the mechanic was actually quite helpful. If all the lights are out and it sounds OK, keep on driving until it makes a worrying and unusual noise.

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Mon 22 Feb 2016 14:07
Toyota Yaris - Toyota Yaris Engine Light Stretched Timing Chain - Rih26
Thank you all for your responses and reassurance. Had a bad experience with an old car so I like to make sure everything is ok! Had to book the car in with Toyota for it's airbag recall so had a chat with them about it, they said they will run another diagnostics on it if I want, but as the light has reset and not come back on it suggests that it's ok. They said if the light comes back on then call them and book it in. The car drives absolutely fine, no noises or strain and the milelage is pretty low. I'm the second lady owner, maintain it will so really hoping that light just stays out! Thanks again to you all :)
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Mon 22 Feb 2016 18:21
Toyota Yaris - Toyota Yaris Engine Light Stretched Timing Chain - Cyd

As you've had to jump start the car (presumably for a flat battery - though you don't say why it was flat, eg normal use or left on a light) I'd suggest you charge the battery properley and also have it tested. It may be the battery is old and on its "last legs". You cannot fully charge a discharged battery by driving alone - it will need charging with a charger

To look after your timing chain, your best friend is regular oil changes. HJ recommends twice a year. Most chains are lubricated by oil draining back from the cam area and any sludging up here can starve the chain of oil, which can lead to catastrophic failure.

It is possible the low battery voltage caused the ecu to throw spurious fault codes, but I suggest you are wise to take the code seriously and have it checked (see above posts).

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