Getting codes C0279, C1213, C1259

It is probably a bad relay.

If they decide that it is an ECU, don't buy a new one, there are plenty of salvage ones out there.

 

Nope, nobody does. A diagnostic trouble code isn't an oracle that tells anybody what needs done to fix the problem. It can only report what problem symptoms the system was able to detect. Now it's up to you or your mechanic, using your knowledge of how those systems work, to work through the things that could possibly cause those symptoms and think of tests you can do that will eliminate some possibilities until you're down to the actual problem. Then you can think of what you could do that would fix it.

The most useful code to start with here looks like the C0279. The computer is telling you that the +12 volt circuit supplying an antilock brake relay isn't able to have +12 volts put on it because somewhere it is conducting to ground with less resistance than the relay coil (edit: see next post). That's all the computer knows. There could be damaged insulation on the wire anywhere between the control unit and the relay. Insulation could have failed in the relay coil itself, or in whatever sources power onto that circuit. The shop manual and the electrical wiring diagram will tell you what all the parts are in the circuit, the color code of the wire you need to be examining and exactly where it runs. You can see these manuals online at techinfo.toyota.com for a small subscription fee or you can buy paper copies from their Materials Distribution Center (800)622-2033. The manuals also have step-by-step tests for each trouble code; if you look up C0279 you should find suggested tests in an order likely to home in on the source of the trouble quickly.

C1259 is a code logged in the HV ECU when there is some problem with the braking system. The C0279 is a problem with the braking system so I would concentrate on fixing that, then clear the codes and see if the C1259 comes back.

Not so sure about the C1213 but I would approach it the same way: fix the brakes first, then see if it's still there.

Hope this helps.
-Chap

 

I might have got that wrong. "+B short" may mean that the control line is somehow getting +12 volts put on it even when the control unit isn't trying to - which could mean insulation damage next to another circuit that is carrying +12 volts ... not insulation damage conducting to ground.

I think you earlier posted about noticing your brake accumulator pump sound more than you were used to. I wonder if these things could be related. If there is a braking solenoid circuit that's getting +12 volts shorted onto it at random times, perhaps it leads to accumulator pressure being used up faster than usual, and therefore the pump running more.

Just speculating....

-Chap