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Discussion Starter · #1 ·
The car engine shuts off while decelerating, send it to the dealership, it's both battery and alternator problem. The quote was about $2,300 ($250/h labor). Bought a new battery, and drive it to my mechanic to replace the alternator. However, I might got a wrong battery


and the battery gauge read is below 14..... Window Automotive tire Automotive lighting Steering wheel Automotive wheel system
but the car drives fine.

Read some forums, 24F is an alternative fit, just less reserve....and if I don't tow, this battery should be fine. Call AutoZone, I can't return/exchange once the battery is installed.

The voltage read is 12.6 when the engine is off, and 12.3 when the engine is running. Should I get a 27F battery instead?
 

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Are you using a multi-meter to check voltages or just that dash gauge?
Both the 12.6 and especially the 12.3 are too low. Either the alternator is sketchy or there is a major draw on the charging system. That battery should be fine, it's a charging issue and the battery is doing the heavy lifting.
You didn't say, did it get a new alternator? Reman or new? Brand and source?
 

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Discussion Starter · #3 ·
Are you using a multi-meter to check voltages or just that dash gauge?
Both the 12.6 and especially the 12.3 are too low. Either the alternator is sketchy or there is a major draw on the charging system. That battery should be fine, it's a charging issue and the battery is doing the heavy lifting.
You didn't say, did it get a new alternator? Reman or new? Brand and source?
I use multi-meter to check the voltage. If I remember correctly, the gauge should stay in the middle at about 14, correct? My mechanic replaced a new alternator but I do not know the brand and source. It's a garage in a gas station, I will ask him on Monday.
 

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Discussion Starter · #5 ·
If it was a reman unit could have a bad diode or the internal regulator isn't working properly.
Running should see about 13.7v min.
Went to AutoZone this afternoon. The battery test is good, charging is good but as soon as start the car, the voltage is ~12.3......Autozone did a start test and it shows a charging failure (alternator). I will go back to my mechanic tomorrow morning.

Thanks for sharing.
 

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Discussion Starter · #6 ·
This alternator + battery problem started with the VSC light on. That's why I send the car to the dealership to diagnose. The report shows the low voltage trigger for the VSC light. Anyhow, I send the car back to my mechanic who insists I need a bigger battery. For the sake of argument, he replaced the battery - Interstate for $160. Start the car and the voltage is 13.6....on the way home, I did notice the battery gauge dropped a little, just a little when I am about to full stop. Once the car full stop, the gauge return to the middle. When I got home, pop the hood with the engine on, and test it with a multimeter and it stays at 13.6-13.7. Is this normal?

But this morning, when my wife start the car, the VSC light is on again. Now I am confused..........
 

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Not that I'm aware of which may not be saying much. Since that is for the traction control system which includes the throttle pedal, MAF, ABS, Wheel speed sensors etc. Where the p2440 is a common vacuum switching problem (emission related I believe) Toyota has had since 2004 or maybe even earlier. There are TSB's out there on it. Being an 2008 I don't believe any response Toyota took on that system would still be in effect, you'd need to read up on them.
281 I ran across.

If the P2440 gets bad enough I'm pretty sure it will put the Vehicle in "Limp" Mode to protect it, It did on a friends 2004 Sequoia but I don't know all the details she could have had other issues too.

Some owners hit with quotes in the $3k to $k range have gone to this bypass kit.
Again, research, it has a decent reputation on the Tundra Owners Site but I think some States won't allow it.
 

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Discussion Starter · #10 ·
Not that I'm aware of which may not be saying much. Since that is for the traction control system which includes the throttle pedal, MAF, ABS, Wheel speed sensors etc. Where the p2440 is a common vacuum switching problem (emission related I believe) Toyota has had since 2004 or maybe even earlier. There are TSB's out there on it. Being an 2008 I don't believe any response Toyota took on that system would still be in effect, you'd need to read up on them.
281 I ran across.

If the P2440 gets bad enough I'm pretty sure it will put the Vehicle in "Limp" Mode to protect it, It did on a friends 2004 Sequoia but I don't know all the details she could have had other issues too.

Some owners hit with quotes in the $3k to $k range have gone to this bypass kit.
Again, research, it has a decent reputation on the Tundra Owners Site but I think some States won't allow it.
The car is in limp mode, disconnect the battery and the car runs normally. Brought to my mechanic this morning, show him the code and he has the same response - it's not as simple as replacing the pump, it can be a variety of things. It could cost a few thousand. I might just trade it in at the dealership or sell it to my mechanic.

Anyhow, really appreciate your time and input. (y)
 

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Might consider this route if ya don't want payments or can't find a vehicle you want. Very popular on the Tundra Owners Forum since they have the same expensive problems.
 

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Discussion Starter · #13 ·
Thank you all for the input. Brought the car to my mechanic, and show him the ODB code, his first reaction is, it's not an easy fix, and might cost me a couple of grand. I end up selling the car to him. Again, thank you all.
 
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