Random issue already...

Well i just got my jeep about a week ago and the check engine light comes on one day then off the next and so on. Then it flashes and shuts off im going back to dealer monday but id like to try n find out why its happening. Have any of you had this happen befor?

 

Check Engine Light can mean any one of ~30 faults. Flashing CEL is pretty bad - usually it means the ECM is detecting (rightly or falsely) a condition that can quickly damage the engine or the catalytic converters.

If you want to diagnose it yourself, get a $20 Bluetooth OBD2 dongle (e.g.

for Android Phones ONLY - Wireless Bluetooth Diagnostic OBD2 Scanner Car Code Reader and Scan Tool for All 1996 & Newer Vehicles ELM327 Compatible OBDII

https://www.amazon.com/BAFX-Products-34t5-Bluetooth-Android/dp/B005NLQAHS/ ) to read the codes and look at real-time data. Also get some basic electrical diagnosis equipment like a

OTC 3636 Heavy-Duty Coil Cord Circuit Tester

test light,

$28 Etekcity Digital Clamp Meter Multimeter AC Current and AC/DC Voltage Tester with Amp, Volt, Ohm, Continuity, Diode and Resistance Test, Auto-Ranging, Red, MSR-C600

multimeter, and

$14 Lisle 65150 Flexible Back Probes

back probes. None of these are expensive and will pay for themselves the first time you avoid the dealership. Read up on the service manual to see how the codes are tripped and test the wiring and components.

As time goes on, you may want to get a Chrysler-specific OBD2 tool (e.g. http://www.ebay.com/itm/V17-03-01-w...g-Tool-for-Chrysler-Multi-Langu-/152465813137 ) that can also read data/codes for ABS, airbag, transmission, antitheft, etc. as problems develop. It's all part of Jeep life, and the JK has more computers than previous generations.

 

Thank you for the help its just kinda odd that it comes on and off again

 

^Depends on the fault. For some faults, the light will extinguish if the out-of-spec condition is not detected for 1-2 drive cycles.

Are there any other symptoms? Is the engine shaking (indicative of cylinder misfire)? Do you hear any hisses under the hood indicative of air leaks?

 

Ohhh ok now im starting to understand thanks again for the help

 

Engine does shake a tad bit when the lught comes on but thats about

 

^That's probably a misfire, which could be caused by lack of spark, fuel, or compression. Don't leave it uncorrected, as misfire could mean unburnt fuel is being sent down the exhaust, in which case the catalytic converter could burn up pretty quickly.

 

Put a bottle of gas line antifreeze in the tank; isopropyl alcohol type only. If the new jeep has sat for a few months not driven regularly, water may be in the gas, which would cause the engine rough idle and CEL light alerts.

 

Awesome information, I'll look into this myself. Tired of bothering my buddy (a mechanic) everytime I want a readout.

 

Ill look in to this more when i get outta work thanks for the help guys.. the light is off again now but can i still tell if it has a misfire with the light off?

 

Since the Jeep is new to you, I would want to check the spark plugs for gap. I know on the straight 6 engines, the plugs are only good for about 30,000 miles. Our 2004 Grand Cherokee had a misfire due to worn plugs. Hope this helps.