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Discussion Starter · #1 ·
Hello, Mazda 3 2016 2.0 MT. The car turns normally but does not start. No spark, Forscan can't see RPM. The voltage on the crankshaft and camshaft sensor is. Sensors replaced with others, 100% efficient. No errors. The power supply after the ignition is turned on is on the ignition coils. No injector control. Any ideas?
 

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2016 Mazda 3 Sport 2.0 Automatic
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Are there any broken, loose or corroded wires from the crankshaft and camshaft sensors to the ECM? Did you test the mass air flow (MAF) sensor, the manifold absolute pressure (MAP) sensor and the throttle position sensor?
 

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2016 Mazda 3 Sport 2.0 Automatic
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Get the ECM out, check for corroded pins, open it and check for any burnt circuit. It is unlikely, but just to be sure as it will not take much time.
 

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2016 Mazda 3 Sport 2.0 Automatic
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Did you fix it?
 

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2012 Mazda 3 GX MT5 non sky
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831 Posts
Any codes ?
 

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If it's not seeing RPM then the crank sensor isn't reading for some reason. I'd start there and work your way backwards. I've seen a number of cars along the way with this issue and it can be frustrating to fix especially if the problem is the crank position sensor itself and it's inside the case. Usually happens when someone does and engine swap from an auto car to a manual car or when someone tries to swap from automatic to manual. These sensors don't generally fail. So I'd start with loose connections rat chew wire etc. as my first repair.
 

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Discussion Starter · #8 ·
The sensor is changed, the voltage on the ankle is there. The computer still does not see RPM, nor does it start the fuel pump. There are no errors. Wires ok.
 

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2020 CX-5 GT 2.5L 2011 3i 2.0L
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The sensor is changed, the voltage on the ankle is there. ....
No idea what you're saying there, but in any case, the crank/cam sensor signals can't be properly evaluated with a multimeter. And installing new sensors doesn't automatically mean the signals are good. It takes an oscilloscope and someone who knows how to read the output, in order to determine if those sensors are sending valid output to the ECU.
 

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2016 Mazda 3 Sport 2.0 Automatic
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I assume you checked the crankshaft and camshaft sensor wires for continuity with a meter at both ends of each wire between the sensor and the ECU. If the wires were only visually inspected confirm Ohms with a meter.

Check the engine ground. Connect your volt meter between the engine block and the negative battery terminal. Crank the engine for a few seconds and measure voltage. If more than 0.1-0.2 volts you have an engine ground issue.

Check the ECM ground. Connect your volt meter between the ECU ground wire pin at the ECU connector and directly to the negative battery terminal with a long cable having alligator clips at each end. Crank the engine for a few seconds and measure voltage. If more than 0.1-0.2 volts you have an ECU ground issue.

Replace the ECM. It is selling online on eBay used for as low as $35.
 
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