No Spark KIA With Fading Power Circuit

Michael Mobile Technician Utah Posted   Latest  
Case Study
2002 Kia Optima LX 2.4L (6) 4-spd (F4A42)
No Codes
Crank / No Start

Got called to a repair shop who was pulling their hair out on a 2002 Kia Optima. The story starts with a bad camshaft sensor. The shop changed the sensor and "ever since" the vehicle would not start. The symptoms were crank and no start. After a few days of replacing sensors, the shop owner discovered that the technician had broken an electrical condenser that mounts on the same bolt as the camshaft sensor. Not realizing what it was the tech stripped the wire installed a connector and tied to ground. The shop owner purchased and installed a new condenser, still no joy.

When I got there there was power to the coils. When the car was cranked, the voltage dropped to 3 volts. After cranking stopped the voltage came back. When I asked if any fuses popped, they told me they could not find a bad fuse. I checked the voltage during cranking at the fuse and there was only a 1 volt drop. I figured this was normal due to starter draw. So between the fuse and the coils the voltage was dropping. With the coils disconnected the voltage only dropped 1 volt at the coil plug. There had to be something in between. The diagram did not show anything??? I decided to go to the dark side and look at their database. Scott Turbeville had mentioned that the ignition failure sensor was a common problem. The diagram did not show one. I decided to go a year newer. There it was. The IFS was connected directly to the condenser. The IFS will cut power to the coils when a misfire is detected. Maybe a strategy to prevent catalyst failure? So by connecting the condenser to ground, the transistor inside was smoked. I did some Google searching on this and saw several posts about bypassing the IFS. I thought before spending more of the shop owners money I would bypass it and see if it would start. I connected the two heavier wires together. (wire colors did not match diagram) What do you know, the vehicle started! So the moral of the story is that if you ground the condenser on a KIA or Hyundai with an ignition failure sensor, it becomes the fuse!


Justin Mobile Technician
Justin Default

I have replaced many IFS on Kia/Hyundai’s in the past. Never for that fault. Interesting note when looking for that part on repairlink you need to look in “spark plugs” not “sensors“.

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Tim Instructor
Tim Default

Alldata also shows the IFS on the 03 but not the 02. I always coach my techs, if something doesn't match, try year newer of older. Ya never know!

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Geoff Diagnostician
Geoff Default

"it becomes the fuse!" - LOL Man-made problems....every single time brother. New flowchart step 1: Get in your time machine and go back to before ANYbody else touched it. :-)

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