RED Triangle light on (PS) off

Check for DTC's using a scanner, such as at Toyota or some auto parts stores. (You can get a basic scanner for less than Toyota's diagnostic fee.) Post what you find back here. It could be the steering ECU, the PS motor, the torque sensor, wiring...

 

Yes, it's a good possibility, from what I hear.

 

I do not think the Autozone scanners can read the Prius specific DTC's but it is worth a try. My guess is that you will need to take it to a Toyota dealer and have the DTC's read. If you do, post on here to get help with analyzing.

 

An ECU from a breakers would be much cheaper and are easy to fit (being plug in) also check out Ebay. The only thing you would need to get done would be a "zero point calibration" some alignment shops can do this.

 

The zero point calibration is basically so that the ECU knows when the steering is in the strait ahead position and does not try to power assist the steering in one direction or the other or give more assist in one direction.

I will try to find where the ECU is located and post. I do not think from memory it is difficult to change.

John

 

Power steering ECU position see attacthed.

Zero point calibration is not a long job about 15mins but does require computer equipment, but should not cost to much especially if you can find an independent shop to do it.

If replace the ECU yourself do a search on dash tear down this should help.

John.

 

BS!!!!

 

The steering ECU is some what deep in the dash above the steering shaft, and is a plug in unit, but the dash on the Prius is easy to dismantle compared to most cars. I would disconnect the 12v battery before dismantling.

 

Yes, you should disconnect the 12V battery prior to removing any ECU. This is especially important since you will be working in the dashboard area as an additional safety precaution considering the SRS system located in the steering wheel hub and passenger-side dash.

Although I have not done this myself, I don't think the removal/replacement task will be particularly difficult once you have removed the two left ventilation ducts and the black plastic dashboard pieces below and above the steering column for access.

 

I looked up c1554 in prius service manual--- relay voltage source or eps fuse blown--- and states relays are built into ecu...
However your c1554 code interpeted by toyota prius tech says c1554 = shorted ecu.....
This (ecu shorted) suggests that the 50 amp eps fuse is blown......This fuse is not easily replaced as it is one of manny high power
fuses stamped out of a single piece of metal composing many fuses...
If this 50 amp fuse is blown its suggests problem could very well be the power steering electric motor is bad and is the only component
capable of of blowing a 50 amp fuse... in my opinion...

The fuse is located under the hood on drivers side.. but does not look like any fuse you ever saw... look for two white plastic strips
just below or in front of red jumper start cover.... these two white plastic strips have a clear plastic viewing sheet on top to view
multipul high power fuses all stamped from single strip of sheet metal... look at diagram for 50Amp eps location. The actual fuse
part looks like a curly cue strip about 1/16 inch thick and 1/8 wide? which looks crimped to wire on one end...

Anyway electric ps motor is a brush comutator type in gen II prius. The brushes will eventually wear down and pull high current at
which time may also blow ecu relays? These brushes are usually replaceable and most motors.. but I don't know if the prius ps motor
brushes are replaceable or it the motor is just disposable.....

If 50 amp eps fuse is not blown its probably just ecu .... to replace 50 amp fuse looks like a major job...If 50 amp fuse is blown
the area backed by white plastic strip will be black and curley cue strip of metal will be burnt into (open) ...

Let us know if 50amp eps fuse appears to be good or not....

Gen III ps motor is not a brush type but brushless type....

 

Yes, if damaged, the fusible link assembly within the main relay/fuse box will not be easy to change as I believe it is necessary to raise up that box for access to the underside.

 

In my experience brush wear creates an *open* circuit condition, and the motor usually just stops, as it does, for example, in the Prius blower motor. I don't know if the steering motor is the same type.