Hey all,

Any help or advice would be greatly appreciated. During a late night jump start recently of my 2009 G37x, polarity was reversed for about ~10 seconds. Once realized, things were made right and the car started.

Now, the TPMS light blinks for 60 seconds after startup, then goes solid for the remainder of each drive, indicative of a TPMS malfunction. No other lingering issues have been observed.

Any advice on what to do, what to check, where to look, or anything I can diagnose without taking it to a mechanic?
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Thank you!

 

Pray you didn't damage your bcm

 

How would I know? If a $120 eBay part fixes my problem I can live with that.

 

Your TPMS light can mean 1 of 3 things:
¹ wheel sensor went bad/dead battery;
² because of the reversed polarity the TPMS module "lost" sensor radio data (ie. was "reset");
³ the TPMS module was damaged.

Assuming you had no issues with the TPMS light prior to getting the jump start, the issue is likely either #2 or #3.

Most tire centers will test your wheel sensors and determine if they are good or bad at little to no cost. Depending on the shop, they might even reprogram the sensors/module for no charge as well.

There is a procedure in the FSM (2009 WHEEL/TIRE FSM) where you can reprogram the sensors without a scan tool.

If the TPMS module is shot there are a ton on eBay for $20 or less. TPMS wheel sensors will run you $35-50 depending on vendor. You will still have to reprogram the sensors even after replacing the module.

 

Thanks ILM-NC G37S. That's super helpful. Guess I've got a couple of different options here so far as troubleshooting myself versus taking it into a mechanic.

 

FWIW, my light has been blinking for over a year now. I know I have to replace the sensors (they are 2008 originals), but am waiting until I need tires. As much as I drive the car that'll be a other 2-3 years or so, but...

Unless your annoyed at the light, it will not damage anything if you put it on the back burner for now...

 

Unfortunately, I am the type of person that struggles to move forward in life when there's a dash light on. Also like the idea of the car always being in a solid state for a sale for if/when I find a replacement over the coming month.

Anyway, yeah, I am exceptionally annoyed with this TPMS situation.

 

If you can't live with the TPMS light, go to a tire shop and ask them to re-sync the TPMS with the tire pressure sensors. If they can, you are good to go.
If they can't then it is time to trouble shoot the TPMS module or BCM or some other module.
By the way, the $120 ebay BCM will need to be re-programmed so your car will start, if the dealer doesn't insist on buying a new "blank" BCM.

I hope I am wrong, but I suspect this won't be a cheap or easy fix. Electronics don't like reverse polarity.
Good luck!

 

discount tire has wand tool to reset tpms for free. Your bcm going bad will make it seem like your car is cursed doing odd things. Also the obvious check all your fuses from the backwards jumping you probably blew a few since that's the job

 

Thanks all. I'm currently in search of a local mechanic that can do TPMS work in an effort to avoid the dealer as well as tire chain stores. In the meantime, kind of wondering if I shouldn't just try a TPMS module off eBay.

 

Why replace something that may or may not be bad? As mentioned before, it could be something as simple as the wheel sensors needing to be re-synced. Or, maybe a wheel sensor went dead- just one dead sensor battery and the idiot light turns on. Worst case the module is dead. Until the issue is properly diagnosed, throwing parts blindly at the problem is not a solution.

If you do replace the module, you will still have to get the wheel sensors synced to the replacement module- assuming the sensors are good to begin with. Replacing the module will not automatically turn the idiot light off.

You do not need to go to a car mechanic to get the TPMS checked. Any reputable tire shop can sync/troubleshoot the issue in under 15min. for little to no cost. All it takes is a TPMS scan tool. A mechanic will charge $$$ just for his time. However, your car- do as you will.

Best advice, until you have the issue properly diagnosed and a plan for repair in place, just deal with the idiot light. Just my 10¢.

 

Found a reputable shop. They synced everything in 15 minutes and we're good to go. 😉

Unfortunately, he also found a bunch of other totally unrelated issues....

 

At least one problem is solved. Thanks for the update. Good luck with the other issues found- if I/we can be of any help...