My friend's XG300 quit running while driving down the road. He towed it to my house, lucky me. There's no fuel pump or ignition power. I narrowed it to the crank position sensor, although there's not a crank position CEL.

At the crank sensor, I get ground, 12V and 5V with sensor disconnected. But when I connect it the 5V drops to zero. Then I have 12V, 0 and 0. Other sensors such as the cam sensor, stay at 5V even when connected.

I'm assuming the crank sensor is bad, but don't know if I have to pull the balancer to change it. Will the balancer come off without a puller, or is it a press fit?

When I plug in or disconnect the crank sensor, the fuel pump runs for a second each time. This is why I think the crank sensor is bad.

How do I get to the main computer? I was thinking it was behind the temp controls but I didnt see it.

Any advice would be greatly appreciated.

 

UPDATE: I finally found a really good write up on how to test hall effect CRK sensors. My crank sensor is working fine, so starting all over again on figuring out this car.

Manually turning over the engine reveals the CRK sensor output goes from 0V to 5V for each cylinder. It's working normally.

So I don't know why the engine won't start and fuel pump won't turn on. The fuel pump does turn on if I disconnect and reconnect the CRK sensor, but no fuel pressure shows up while cranking the engine- so I know it's not turning the pump on while cranking.

If I reset all CEL's, and rescan, I always get a P0103 MAF high input code. This car has been throwing this code for months and still drove fine. It's a new MAF sensor too, because the old sensor threw the same code.

 

Ok the Hyundai website has had me troubleshooting for HOURS. I keep getting the same final guessanalysis that the "Power Transistor" is bad. Ok that's great, but WTF is it. I can't find it in any parts cataloge or parts supplier. I don't know where it is to even troubleshoot the connections.

I originally thought it was the ignition misfire sensor, but after reading numerous posts from others, I've second guessed myself and am thinking it's some sort of relay or other thing that allows high current to/from the coils. Besides that, I changed the misfire sensor, and the ECU and same problem.

The car was driving fine and then just shut off at 45 mph. So I can't logically say that all 3 coils went bad. And since I'm getting solid power and ground, plus an intermittent 3-4 volts at the coils signal, I can't imagine why it's not starting or making spark.

Any ideas? ( I HATE this car)

 

I believe the "power transistor" is just the ignition module. Not sure where it's located on the XG but I would assume near the coils. Look like this:

 

The only thing that looks like is the ignition misfire sensor. The thing that's driving me crazy is that the factory troubleshooting procedure consistently and repeatedly says to check various pins on the Ignition Misfire Sensor harness. It says those exact words over and over in different test procedures. Then the conclusion is to replace the Power Transistor. If they were the same part, then the conclusion should have said to replace the Ignition Misfire Sensor. I'm baffled why it would suddenly change the name of the part.

I'm getting all the correct power and ground to the coils, and the switching voltage on pin 3 that is supposed to be there to fire off the coil, but the coils wont work- none of them.

 

No, that's the "power transistor" which is the ignition module. If the ignition module is bad, the coils won't fire.

 

@joezek, since your car isn't firing and there is no power coming for ignition, that means that there is an issue with the ignition circuit. I know you'd be saying that everyone knows that but for troubleshooting, we need to devise reasonable steps to get to the bottom of any issue. Now what's in the ignition circuit, a coil, an IC and an input coming to that IC? Try checking the number on that IC and download its datasheet. I'm guessing it's the infamous power transistor you've heard so much about. Now check at its input if it's getting a signal, if it is, you've got your perp. If it isn’t getting a signal, we'll need to go further back to ignition source. Do tell us what you find out.