Long story over months this summer. Battery completely discharged and car was dead. Battery would not take a charge, replaced the battery and the alternator as it was not charging. This fix lasted about 3 weeks and car went dead on the highway at 60 mph, complete discharge no power. Towed to Toyota who scanned, reset, etc., after a week they could not identify a cause as it was intermittent and I took the car back. Credit to the Toyota dealer who did not charge me since they couldn't fix it.

I bought an OBD reader and started monitoring. The battery voltage varies from 14.1 down to as low as 10, then will jump back up and start charging again. Inconsistent as hell, sometimes there sometimes not. OBD is currently showing codes C0273, C0278, C1225, C1226, C1227, C1228, C1231, C1241. These have been fairly consistent over the last month or so.

Questions:
Is there a common component that could be failing to generate these codes?

Is there a specific grounding block or wiring harness that I should examine for a short?

Any help is much appreciated, about to give up and buy a different car which is less than ideal in the market place today.

 

How skilled are you at dealing with car electrical issues?

Was the dash board battery icon illuminated with the engine dead on the road? If not suspect a bad wiring connection. Typically on modern cars the engine will not run with the battery disconnected. For starters carefully check ALL fuses including the high amp fuses that are bolted to the fuse/relay box. Has happened a high power fuse filament (the part the melts) can have an intermediate connection. Check battery terminals, battery cable ground chassis points, etc.

The Icon on means the battery is not charging and eventually the battery will discharge. If the engine just dies without any indication of the battery no longer being charged suspect the battery is being disconnected for cars electrical system. There is no disconnect switch as is in the battery is always connected to the alternator. The ign key sets up the charging. Are the ign key switches OK?

How and where are you measuring battery voltage. If at the battery terminals it should read battery voltage when engine off and something like 14V at 2000 rpm.

The codes explanations can be found on the internet. They are related to the ABS and SKID system. Suspect a low or no voltage to the system may cause a few codes. It also may be possible these systems have a problem but don't have enough info.

The charging system is pretty straight forward in wiring design.

If you are up it suggest getting a wiring diagram. Toyota has a website where for $20 can get access to info for 2 days. Or check out Haynes of Chilton manuals.

https://techinfo.toyota.com/techInfo...arch_docs_page



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Thank you, this is helpful. I am reasonably capable of dealing with car electrical systems, not an expert by any means.

The battery light was on along with just about every other warning light on the dash when the car died on the road. My wife was driving so I am not 100% sure exactly which lights were on but the AC stopped, radio went off, and the dash was lit up like a Christmas tree as she described it. Currently when the voltage starts to drop various warning lights will start coming on, traction, battery, etc. and occasionally the radio will shut itself off.

The battery voltage is what I am able to pull from the OBD monitor and logs. When I put a meter on it I get 14 volts with the engine running, unfortunately I have not been able to replicate the faults in the driveway. Battery cables and terminals are solid, no corrosion or frayed wires.

Agree that a blip in voltage could trigger the codes I am getting, not exactly sure how to test the various components that are associated with the codes to separate a malfunction from a voltage problem. I have not checked the bolted fuses but will do that and will see if I can pull a wiring diagram to trace the grounding points. My thought is that I am chasing a bad or damaged wire, connector, or ground point. Of course that could be anywhere in the wiring harness, the needle in the haystack. Thanks for taking the time to respond.

 

I suggest being more optimistic! Dealing with Toyota electrical issues is FAR easier then some cars like BMW.

If the engine quits but electrical power remains on all those dash indicator lights will come on.

Suppose it was a momentary lost of electrical power that caused the engine to quit. Being an automatic transmission if electrical power was restored (a momentary lose) the engine is not going to be mechanically driven to restart as with a stick shift. Did your spouse attempt to restart the engine?

The radio and AC blower not working is another indicator. The radio may not come back on without turning it on after a power failure but the AC blower might. Did the blower come back on after the engine died?

If you are going to plan to try to fix the car get a wiring diagram.

There is only one 12+ power source to the engine, radio and A/C. Yet pretty much every electrical item has its own chassis ground point. This as opposed to cars were grounds are gained up in units of say 5-8 and then attached to the chassis as one ground point. In your case if its a grounding issue suspect its something like a bad battery ground cable or connection but you stated this was not a problem.

Check 120A ALT fuse. The wiring to it is bolted on from behind the board its on.

The other place to check is the fusible link in the positive battery cable. This cable runs from the battery to a fuse box and has an inline fusible link.



Post back with your response and will move on from here.

Also, did the Toyota dealer change any electrical parts.

 

When it died on the highway the car would not restart, the AC fan and radio did not come back on as the battery was low enough that even the power locks were in operable.

No parts were changed by the dealer, they recharged the battery, tested the alternator, ran various system scans, they resorted to resetting the ECU. The car has not died on the road since but continues to have intermittent issues.

I have not had a chance to dig into your suggestions about the fusible link and the 120A fuse, will be able to work on those this week. Thanks for the assistance.

 

Are you stating the battery was dead or voltage very low but the battery dash icon light never came on prior to this to indicate it was not being charged?

A dying battery can cause an engine to quit.

Suggest installing a volt meter. There are low cost meters that plug into the cars CIG lighter or power outlet. Educate the spouse on what normal voltages are, engine off and at 2000 RPM. If the voltage indications start to lower caution spouse to get home and have it checked out.

On a side bar note, sometimes something is not turning off when it should. Some years of Toyota has issue of the HVAC blower coming on when the car was parked, issues with the power locking system. After market items such as alarms, stereo amplifiers can cause issues of power drains.

If then a low battery it may not be a wiring issue. Low voltage can cause all kinds of issue setting OBD codes. Suspect a bad alt regulator or battery. The battery not charging indicator is wired to the alt. Make sure the dash icon comes on when ign key is turned on.