Voltage fluctuation and error codes

rockporiom · Mon Jun 23, 2014 9:32 pm

Hey guys

This is my first post on this forum. I own a 2011 Kizashi MT in India. Now I have been facing this problem from a long time on my Kizashi and the service centers here are clueless and are also inadequately trained due to the poor sales figures and the recent discontinuation of the car in India.

The car throws a Service start system error for a few seconds and then disappears without any codes in the OBD reader. The longest the error stayed was for a minute. The car has heavy voltage fluctuation with fluctuating horn tone, reverse lights, brake lights, head lights, interior lights almost all lights :facepalm:

. Now this happens only when the car is running. The error usually comes while starting or switching off the car or when there is start and stop traffic.

I read the other posts but my cars audio system and DC sockets are working alright. I am completely confused. My push button system also works completely fine. All the service centers have different diagnosis ranging from wiring fault to battery to alternator to earthing.

i changed the horn under warranty about 6 months back and the problem has started after that.

Any help would be appreciated.

Thanks in advance

Mon Jun 23, 2014 10:44 pm

To me, it sounds like an unstable/faulty alternator but make sure all the wiring is properly connected first. Check the wires to the alternator and make sure ground wires are grounded properly.

rockporiom · Mon Jun 23, 2014 10:58 pm

Hey thanks for the quick reply.

I got the alternator checked by denso who is the manufacturer. They observed heavy carbon deposits in the alternator and have cleaned it. But that didn't solve my problem. I got the ground wires checked and they are connected OK. The last 2 things remaining are the battery and alternator. The battery is just 1 year old so I doubt that it can be the problem I get 12.43v on idle and 14.4v at 2000 rpm. While cranking it goes to 10.3 and then comes up again. but everything fluctuates. The service center uses a bosch unit to diagnose problems with the alternator and the test always comes ok.

murcod · Tue Jun 24, 2014 1:16 am

rockporiom wrote:The battery is just 1 year old so I doubt that it can be the problem I get 12.43v on idle and 14.4v at 2000 rpm. While cranking it goes to 10.3 and then comes up again. but everything fluctuates. The service center uses a bosch unit to diagnose problems with the alternator and the test always comes ok.

Hi. That voltage at idle is way too low. Here's what I measured on my Kizashi a few months back:

Did some testing today. Engine idling, low beam on - head light voltage at rear of the bulb= 13.95V ; battery voltage was 14.46V at the same time.

I'd suggest it's likely to be a battery problem (possibly the alternator, but you've had that checked already- did they check the regulator and load test it?) Don't assume because the battery is only 12mths old that it is okay. It sounds like it could be draining a lot of current, too much for the alternator to handle at idle RPM.

I recently had a similar thing happen on my XL-7. The local road side assistance mob couldn't diagnose it and said it had major electrical problems. It was just the battery - one cell must have collapsed. The electric windows would intermittently function, the same with the radio and A/C. The more revs the better it ran. The battery voltage measured okay and it charged okay too! But I left the battery sitting (disconnected) for a week and it quickly dropped to around 8V. A new battery fixed it.

~tc~ · Tue Jun 24, 2014 1:44 am

If your voltage is <13 V or so, you are not charging the battery because there is not sufficient voltage to overcome the internal resistance of the battery.

murcod · Tue Jun 24, 2014 3:23 am

As long as the alternator voltage output is higher than the battery voltage you will get current flowing charging the battery. The problem is the charge voltage level is lower than it should be- so there is either a huge drain on the alternator dragging the voltage down (dieing cell in the battery?) or the alternator is misbehaving.

As an example, I've got a small off grid 12V solar system at home. It's overcast and raining at the moment- so not much charging is happening. The battery is sitting at 12.4V and the solar panels are at 12.5V - that's enough difference to still be charging the battery at 2.0A. As the battery charges (voltage rises) the solar panel voltage will climb also- but charging will be very slow (and the battery is unlikely to fully charge.) On a sunny day I can get 22.5A.

rockporiom · Tue Jun 24, 2014 6:05 am

~tc~ wrote:If your voltage is <13 V or so, you are not charging the battery because there is not sufficient voltage to overcome the internal resistance of the battery.

The voltage goes below 14 only on cranking and idle but the service station says that during cranking 10 and above is good. The battery doesn't go below 14.3 when the car is switched off. When I accelarate in neutral from idle all the lights become very bright as if they are going to burst.

In fact the fluctuation is so high that when I brake hard the horn stops workings. The horn has single tone when the car is off. The horn tone changes on the basis of accelarator input.

murcod · Tue Jun 24, 2014 8:36 am

I added some more info to my original reply.

A battery can measure a high voltage (eg. the 14.3V you mentioned) when the engine is first switched off. It's called a "surface charge" and doesn't give a true indication of the battery's health.

The first rule with fault finding electronic problems is to check the power supply first. The abnormal levels you've got could well be the cause of the "Service Start System" message.

Load testing of your battery and alternator would be a good first step. Even borrowing a known good battery to try it out.

PS: You haven't had any dealer fitted accessories done in India have you? http://www.kizashiclub.com/forum/viewto ... =12&t=2477

rockporiom · Tue Jun 24, 2014 10:08 am

murcod wrote:I added some more info to my original reply.

A battery can measure a high voltage (eg. the 14.3V you mentioned) when the engine is first switched off. It's called a "surface charge" and doesn't give a true indication of the battery's health.

The first rule with fault finding electronic problems is to check the power supply first. The abnormal levels you've got could well be the cause of the "Service Start System" message.

Load testing of your battery and alternator would be a good first step. Even borrowing a known good battery to try it out.

PS: You haven't had any dealer fitted accessories done in India have you? I added some more info to my original reply.

A battery can measure a high voltage (eg. the 14.3V you mentioned) when the engine is first switched off. It's called a "surface charge" and doesn't give a true indication of the battery's health.

The first rule with fault finding electronic problems is to check the power supply first. The abnormal levels you've got could well be the cause of the "Service Start System" message.

Load testing of your battery and alternator would be a good first step. Even borrowing a known good battery to try it out.

PS: You haven't had any dealer fitted accessories done in India have you? http://www.kizashiclub.com/forum/viewto ... =12&t=2477

I have fitted an original park assist system with camera and display in my car. What do you mean by load testing? Do you mean switching on everything and then testing?

murcod · Tue Jun 24, 2014 10:55 am

An auto electrician should have equipment to load test both your battery and alternator. That means testing them under full current load - so basically checking the capacity of them both to meet their rated outputs.

Denso should have done that with the alternator (not just cleaned it)- but perhaps they didn't?