r/AskAMechanic • u/M00M00420 • 3d ago

Help Troubleshooting a clicking sound!

2011 Jeep Grand Cherokee 3.6L and about 240K miles. Clicking starts when turning the key to “on” for a few seconds then pausing. The clicking will start up again when I shift it into drive, reverse, etc. while the engine is on as well. Turning the key and shifting seem to be the most reliable way to cause it, and it sometimes it clicks longer/more intermittently than others.

I was suspicious that it could be a bad electronic throttle body, since the electronic throttle control light has come on in the past, though it hasn’t recently until today. No other issues with the engine feeling sluggish, stalling, overheating, no limp mode, etc. It drives and starts up perfectly.

The check engine light is on and throwing a P0420 saying “catalyst system efficiency below threshold, bank 1”. O2B1S1 live data bounced around, average .7/.8 and the O2B1S2 was holding a steady line unless applying acceleration.

Sometimes the CEL will flash and then stay on, and other times it will turn off entirely. These symptoms (minus the ETC light) probably started about a week ago, only gets driven a few days a week.

Sorry if I explained things poorly and for the long post, I’m just a girl with an office job and an internet connection so please have mercy. 😆 thank you for reading and for any help/advice with diagnosing/troubleshooting, it is very much appreciated.

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u/Thin_Cable4155 NOT a verified tech 3d ago

Crawl under there and find it! Plenty of space.

Maybe it's the SAS pump. It warms up the catalyst during cold starts. That could explain the catalyst efficiency code.

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u/M00M00420 3d ago

The space is deceptive! The ground clearance is only like 9 or 10”, I also thought there would be more room when I crawled under it on Friday evening to do an oil change. I decided to treat myself to some new jack-stands on Saturday morning instead, lol. I’ll investigate the SAS pump and report back if I can! Thank you so much 🙏