Intermittent starting problem

[Adrian Clark]

Just bought my car 1 month ago - my first hybrid 😊

Getting intermittent - but increasingly regular problem starting car. Alarm going off and dashboard warning says "hybrid system disabled"?? Switching ignition on and off, pumping break, turning steering wheel (not sure why) and problem seems to sort itself after a few minutes. Very frustrating and in contact with the dealer, but wondered if anyone had similar experiences or any thoughts?

Many thanks

[Herbie]

It's under warranty so don't even think about it, just get it back to the dealer (but I'll hazard a guess that the 12V Battery may be on its way out).

However, as it's your first hybrid you may just not have the hang of it yet because they are quirky. Apologies if you already know this but....

Press the brake pedal and press the 'Start' button, and if everything's alright then a few seconds later you'll see the green 'READY' light and off you go.

The start-up sequence is that the 12V Battery boots the computers, pressurises the brakes (interesting to note that you mention pumping the brakes!) and gets the car into READY mode, which is equivalent to a conventional car idling with the engine running and the alternator spinning. At this point you can drive away on Battery power alone and the hybrid system will decide when it wants the petrol engine to run.

Hybrids don't have starter motors or alternators. When the petrol engine needs to run the hybrid system energises Motor/Generator 1 (MG1) and uses that to spin the engine up to 1,000rpm before applying fuel and a spark to fire it. The job of the alternator is done by the hybrid system, traction Battery and a DC/DC Converter that takes the 300-ish volts of the traction Battery and lowers it to about 14.5V to charge the 12V Battery and run the 12V electrical systems.

Because the engine doesn't run all the time anything normally driven by a belt, such as the power steering pump or the aircon compressor for instance, is again driven by the traction Battery via converters and/or inverters. The aircon compressor, for example, is driven by a 500V 3-phase AC variable frequency motor; power steering IIRC is a 48V motor and so on.

If you're still reading this, well done, but I'll stop boring you now 

Usually a lot of seemingly unrelated symptoms often point to a dying 12V Battery, which is why my first guess would be that, but the only real way to diagnose anything is by way of the OBD2 codes. At least you know it's under warranty and the dealer will get it sorted for you.

Please let us know the outcome as it helps others in the future