My Rav4 is currently at 73,500 miles. It have been idling rough in Park. You can feel some vibration in the seat when you focus on it. When I don't have the AC on nor the defroster nor the headlight, the car idle at 600 in Reverse and Drive. One thing I notice when I come to a full stop a light and turning off the headlight, the rpm would drop very close to 500 rpm where it vibrates and it will take around 15 seconds for the rpm to climb back to 600 rpm and stop vibration. I have tested the car's battery with a multimeter when it is off; it reads 12.6 volts. When I turn the car back on, it reads 13.4 volts with no load. With headlight, AC, etc, it still reads 13.4 volts. Anyone have a clue what is causing it?
18 Rav4 battery voltage at idle
RAV4SEtesting
1 - 6 of 6 Posts
My Rav4 is currently at 73,500 miles. It have been idling rough in Park. You can feel some vibration in the seat when you focus on it. When I don't have the AC on nor the defroster nor the headlight, the car idle at 600 in Reverse and Drive. One thing I notice when I come to a full stop a light and turning off the headlight, the rpm would drop very close to 500 rpm where it vibrates and it will take around 15 seconds for the rpm to climb back to 600 rpm and stop vibration. I have tested the car's battery with a multimeter when it is off; it reads 12.6 volts. When I turn the car back on, it reads 13.4 volts with no load. With headlight, AC, etc, it still reads 13.4 volts. Anyone have a clue what is causing it?
You probably have an engine management problem (idle speed irregularities, rough idling, etc). Not an alternator problem. Solve the engine management problem first.
It could be be the idle control system, dirty throttle body, or dirty sensors such as MAF. Could also be ignition related such as worn spark plugs, faulty ignition coils, worn out wiring, etc.
Are there any OBD II codes? Most auto parts stores will read the codes for free. That should start you on the way to finding the problem.
After you get the engine management issues solved, that battery voltage does sound a bit low, it should be more like 14+ volts. Quality of the voltmeter used? Your auto parts store should also be able to read the voltage for free. Your battery is obviously being charged. The built in voltage regulator could be bad, or if some of the diodes in the alternator are blown, you can get a low voltage. If some of the diodes are bad, you should hear a whirring sound on the AM radio that varies by engine RPM.
It could be be the idle control system, dirty throttle body, or dirty sensors such as MAF. Could also be ignition related such as worn spark plugs, faulty ignition coils, worn out wiring, etc.
Are there any OBD II codes? Most auto parts stores will read the codes for free. That should start you on the way to finding the problem.
After you get the engine management issues solved, that battery voltage does sound a bit low, it should be more like 14+ volts. Quality of the voltmeter used? Your auto parts store should also be able to read the voltage for free. Your battery is obviously being charged. The built in voltage regulator could be bad, or if some of the diodes in the alternator are blown, you can get a low voltage. If some of the diodes are bad, you should hear a whirring sound on the AM radio that varies by engine RPM.
It is not throwing any code on the code reader. No check engine light. I went to AutoZone for an in-car battery and alternator test. The test passed. The voltmeter is made back Innova.
Have not clean those two yet.
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