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Discussion Starter · #1 ·
Can anyone tell me what the voltage should read on the wires going to the crankshaft sensor and what should be coming out?
 

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Crank sensor is not a switch, it doesn't work that way.
It generates voltage when exposed to magnetic field. That signal is used to determine position of pistons in the engine.

Measuring voltage would give you mean voltage because signal looks like fortress. How much voltage, I don't know but not much. Maybe millivolts. If you have more sofisticated instrument you can try to measure duty cycle.
 

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Discussion Starter · #3 ·
Hi and thanks for the reply. I understand what you're saying but I wanted to know how much voltage there should be should be before it connects to the crankshaft sensor?
 

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No.
Two wires are just closing the circuit. There is no current going into the sensor and both connectors should read 0 volts when disconnected from sensor.

Signal that is generated by the sensor is picked up by ECU and used for calculations.
Sensor is for measurement like a battery, rather then like switch.

Signal is in millivolts and looks like teeth. If peak voltage is 0,05 V and duration is the same as 0 V you will read 0,025 V if you have an instrument that is fast enough and capable of picking up such signal.

Normal way of testing a signal like that is by oscilloscope when you can see voltage, shape of the signal and it's duration, all on screen.
 

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Discussion Starter · #5 ·
No.
Two wires are just closing the circuit. There is no current going into the sensor and both connectors should read 0 volts when disconnected from sensor.

Signal that is generated by the sensor is picked up by ECU and used for calculations.
Sensor is for measurement like a battery, rather then like switch.

Signal is in millivolts and looks like teeth. If peak voltage is 0,05 V and duration is the same as 0 V you will read 0,025 V if you have an instrument that is fast enough and capable of picking up such signal.

Normal way of testing a signal like that is by oscilloscope when you can see voltage, shape of the signal and it's duration, all on screen.
No.
Two wires are just closing the circuit. There is no current going into the sensor and both connectors should read 0 volts when disconnected from sensor.

Signal that is generated by the sensor is picked up by ECU and used for calculations.
Sensor is for measurement like a battery, rather then like switch.

Signal is in millivolts and looks like teeth. If peak voltage is 0,05 V and duration is the same as 0 V you will read 0,025 V if you have an instrument that is fast enough and capable of picking up such signal.

Normal way of testing a signal like that is by oscilloscope when you can see voltage, shape of the signal and it's duration, all on screen.
 

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Discussion Starter · #6 ·
Okay thanks for your time and the info. We still can't get it to start. We have 2.5volts to chassis earth on both wires, across the two nothing. The fault code we're getting is P1808 which is correlation error crank/camshaft sensor.
I can't remember which but one of the sensors needed replacing and it was fine for about 6 months but then it wouldn't start again.
We have since changed both and it still won't start, anymore suggestions would be great thanks.
 

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There is more then one type of hall sensor, I explained the most common one.
2,5V max be used just as reference, easier to read if signal is going up and down from that 2,5.

If you already changed both sensors, they are not the problem.
It's somewhere else even though ECU thinks it is based on data received.
 

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As an example, yesterday I picked up a friend with Mini countryman.
Rubber buffer on crank pulley was shattered and he could not drive any more.
Computer can only see that the generator is not creating any power, sending code: battery charging fault, assuming generator is the problem.
It could not know whether it's from generator, broken belt or pulley.
 

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Discussion Starter · #9 ·
Okay thanks for that, I think we need to investigate a little further and maybe with the valuable information you have given us we can make some progress...
 

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Discussion Starter · #10 ·
Okay so I thought I would update everyone that has helped here. We got the car going in the end, it turned out that the aftermarket crank sensor that was put in couldn't have been working properly.
I tried a second hand crank sensor and hey presto it fired up.
Thanks again anyway for all your input, it was a great help...
 

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Discussion Starter · #11 ·
As an example, yesterday I picked up a friend with Mini countryman.
Rubber buffer on crank pulley was shattered and he could not drive any more.
Computer can only see that the generator is not creating any power, sending code: battery charging fault, assuming generator is the problem.
It could not know whether it's from generator, broken belt or pulley.
Okay so I thought I would update everyone that has helped here. We got the car going in the end, it turned out that the aftermarket crank sensor that was put in couldn't have been working properly.
I tried a second hand crank sensor and hey presto it fired up.
Thanks again anyway for all your input, it was a great help...
 
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