Jeep Cherokee Forum - Throttle Position Sensor & Alternator

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Throttle Position Sensor & Alternator

Well, I took my Jeep out and splashed through some mud puddles and when I left the battery light came on. After a little bit the CEL came on and it would off and on run like crap on the freeway home. Got home and the battery was 12.1V, whether running or not. Battery is only 2 months old. CEL is a P0121 TPS code.

So is it a coincidence that both of these issues show up from splashing in the muddy water and I'll need an alternator and a throttle position sensor or should I wait and just fix the alternator and see if the TPS is fine once the voltage is back up and normal?

It needs a starter too as it has been cranking slow anyways, thinking of taking the starter and alternator to a local rebuild shop.

I have a couple things Nick. The alternator, being where it is with its vents and all appreciates any shielding from aggregate/mud and stuff that might get in its guts. (don't we all!). I'm not a "mudder, or a wheeler or anything" (on purpose), but I've herd of that coming up. Second, out of all the sensors/senders, it's the TPS that really doesn't like getting wet. Guess it has fine wingdings and a "point" that rubs across to deliver a varied voltage to the puter depending on throttle, that get's boogered up wet. On an auto there are two sets of wingdings and two points, working opposite. One for the engine, one for the tranny. (one feeds more while the other feeds less). Pre 91 they are checkable, adjustable. Post 90 they must be checkable, at least. (analogue meter?) Anyway best to not get a TPS wet.

For some years, at least till 90, you don''t need to spend the high $ for a "Manual Trans" TPS, Buy the cheaper auto trans TPS and just hook up the engine side.