Can a low 12V battery cause ABS codes? How about revving the engine in Park?

I have a 2003 Prius with 150K miles on it. 3 weeks ago, there were no issues, except that the battery was at the end of its life expectancy.

Then came the triangle of death. I coasted it home 1/2 mile, looked for codes, and found P3130 and P3125: inverter coolant pump. Because I had my OBD reader out (Innova 340c) and can't leave well enough alone, I also ran through a battery and charging system test. The latter required revving the engine at 2000 rpm for 20 seconds (which wasn't easy with a mushy accelerator pedal) and that's when the ABS and PS lights went on, along with 12 additional DTC's.

I finally drained the inverter coolant and replaced the pump. Went to start the car today and found a dead 12v battery. (I hadn't disconnected the battery while the car sat and I worked on it). Had it jumped and was told that the battery was at 0 CCA but the "alternator" is fine (I thought the Prius doesn't have an alternator). While I was letting the battery charge again, I bled and topped off the coolant repeatedly. I still had the death triangle but no diagnostic codes. On top of being lazy, I also don't learn from my mistakes, so I did the battery and "alternator" test again. Whammo --"The charging system output is high and can cause overheating"; ABS and PS lights are on and the same 12 ABS codes are thrown: C1271-8, C1281-4 (low output voltage of speed sensors, abnormal change in output signals, faulty master cylinder pressure sensor output signal, faulty front and rear pressure sensor output signals). Then after a couple of times turning the car on and off, the ABS and PS lights went off and there are no codes stored. The accelerator pedal is still mushy.

Is all of this a glitch from a low battery? Damaging something from revving the engine ? A coincidental bad ECU or charging system? I ask because I don't want to spend > $200 on a new battery if the car is looking at >$1,000 in repairs.

Thanks all. I'm also happy to share what I learned about changing the pump that I hadn't seen in any threads.

 

Getting a working car after replacing the battery would be a no-brainer, but facing a very costly repair after replacing the battery would be unfortunate. Knowing that these symptoms could be the result of a low battery by itself would tilt me to replacing it.

 

Alas, I moved the car from the nurturing environs of the Bay Area and Luscious Garage to the backwater of Long Island. No citing of a Prius taxi yet!

Funny that you mention the booster pump. Mine failed a week after I took my car to a local shop to get the brakes serviced 2 1/2 years ago. The symptoms then were a brake pedal that was almost impossible to depress, and different codes. It's interesting that even now, I don't have any codes for a low battery or a problem with the charging system, and that the ABS codes disappear even though the accelerator pedal stays mushy. If it weren't for the tangible pedal, I could more easily believe that the codes are just an artefact.

Nice that you have the same car.

Thanks to you and bisco for the input.

 

Huh, I'll look into that. Thanks.

 

It's definitely on its last legs. I was expecting to replace it soon anyway, but wanted the car working and having passed inspection before going down that road.

 

I think a junk yard is in my future. While I’m at it, I can look to replace the headlamp that has a cataract. I’ll report back about my suspicion that I and the Toyota service guy are the only two people on Long Island who’ve ever owned a classic Prius.

 

Back with some clarity and more questions.

I installed a new 12v battery. The charging system appears fine, although I've hardly driven it. The ABS codes disappeared for the first 5 minutes of driving and then came back.

The codes are a straight flush if you've got 12 cards:
C1271-4 (low output voltage speed sensor)
C1275-8 (abnormal change in output signal of speed sensor)
C1281-4 (faulty output signals of master cylinder pressure sensor, regulator pressure sensor, and front/rear pressure sensor).

The brake light isn't on, nor is the main battery light. The car brakes fine, but has subtly more grip and maybe grind.

I bought a 2-day account for techinfo. Searching on the codes, precious little comes up. I would think the 12 together point to one common problem, but I can't figure out what that is.

The list I've found of systems that need to be initialized after reconnecting the battery don't include anything about the brakes. Everything else (including the power windows) is working fine.

I had the wheels aligned before anything popped up, but no codes appeared for a while after the alignment -- definitely not during the 1/2 hour drive home. The codes appeared before I did any work. First sight was when I tested the charging system by revving the engine at 2000 rpm for 20 seconds, while the pump wasn't working and the 12v battery was low. (I will not be doing that again, regardless).

Any thoughts? Please?

 

I'm a little overloaded by the wiring diagrams. Do you happen to know in real space where the connectors might be? (i.e. if I look under the hood, where might I find what I'm looking for?)

 

This is an interesting point. I wonder whether the difference between regenerative and friction braking might cause the difference in sound or feel. The car is driving fine and stopping fine. The speedometer agrees with side-of-the-road readings. The only other thing that seemed off was speedometer readings while I was braking. The 8 mph to 0 range didn't seem right.

I drove the car today about 30mi round trip total. On the trip back, the ABS codes disappeared, but I still have the ! lights. I tried to get to the Energy display but couldn't get past the warning screen. Otherwise, maybe I could confirm the lack of regenerative braking by the arrows.

Can I pull out fuses and relays willy-nilly to look at them, or do I need to take precautions? I wish there was something that mapped codes to fuses and relays.

 

Thanks for your suggestions. I'll look at the fuses before breaking down and going to the dealer for a diagnostic. I just wanted to be sure that I don't have to disconnect the battery, bury the keys, etc.