Toyota Yaris Issue - Need some help

[andywilliams1187]

Evening all,

Looking for some advice regarding an 08 plate 1.3 toyota yaris (vvti) automatic that is driving me mental

Car is the Mrs runaround and it has an intermittent starting problem - sometimes the car starts straight away, other times it cranks once and dies, other times when you turn the key nothing at all will happen. So far the following has been done:

New battery
New spark plugs
OEM alternator fitted
Oil/filter changes
New starter relay
Key fob battery replaced
Battery grounds checked - all good

The battery is good - 12.4v when engine off, 14.2 when the car does start.

I have pulled out the integrated relay pack and tested this as per the workshop manual - there is no ohms reading between b4 and c1 when bench tested, so a replacement is on the way but not sure if this will fix it or not - i have also ordered a new ignition switch as it was cheap enough and easy to do so thought I would try that as well (should be here this week)

Apart from the above, does anyone have any other ideas? Currently loosing my mind with this and problem is getting worse

I was initially thinking fuel pump but think the problem is an electrical gremlin between the ignition and the relays which would explain why sometimes it cranks, sometimes it does nothing (lights radio all workr etc with no dimming)

Any help solving this massively appreciated (or an idea of what to look at next)

[Peter T]

It sounds like a possible inhibiter switch failure. Either the park/neutral in the gear selector mechanism, or the brake pedal. These are what allows the starting circuit to engage allowing the car to start. If either sensor is faulty then starting will abort either before duty cycle of in between. Check these too.