ASE A6 Electrical Electronics Practice Test
6. There are codes indicating misfires at the number 1 and 4 cylinders of a four cylinder engine. According to the diagram above, which of the following is MOST likely causing this condition?
- A. There is an open at point A in the system.
- B. There is an open at point B in the system.
- C. There is an open at point C in the system.
- D. There is excessive resistance at point D of the system.
Answer A is wrong. Point A is a common ground for both drivers. Drivers are transistors. The computer uses them to control different actuators like the coils shown above, usually by grounding the control circuit.
Answer B is correct. An open at point B results in no voltage input to the coil and a misfire code at both the number 1 and 4 cylinders.
Answer C is wrong. An open in the 2-3 coil’s power circuit will result in a no-spark problem with that coil only.
Answer D is wrong. Resistance in the crankshaft position sensor’s circuit will result in a corrupt signal and most likely a no-spark condition at both coils.