2003 Prius: High pitched noise, ABS & BRAKE Lights on

First you need to have EBCM - electronic brake control module check for DTC'S - diagnostic trouble code's . If the light is on there is a code stored . I think most part stores can do this and for free . After you find out what code is stored , looking up that code in service repair information for diagnostic trouble shooting chart would be next step . There are a few codes too.
DTC C0035 or C0040
DTC C0045 or C0050
DTC C0110
DTC C0131
DTC C0161
DTC C0186
DTC C0196
DTC C0201
DTC C0240
DTC C0241 or P0856
DTC C0244 or P1689
DTC C0245
DTC C0283
DTC C0287
DTC C0290 or C0292
DTC C0455
DTC C0550
DTC C0558

Find the code do the diagnostic's , fix the problem , wiring issue's , a sensor , bad module ,what ever it is . The light will go out then . Here is a sample of code discription .
• DTC C0035 Left Front Wheel Speed Sensor Circuit
• DTC C0040 Right Front Wheel Speed Sensor Circuit

VSC ABS and ! lights plus red (!) - Toyota Prius Forum ...

www.priusonline.com/...toyota-prius.../19804-vsc-abs-lights-plus-red.ht...

Jun 3, 2008 - 8 posts - ‎3 authors
If the accumulator fails, you will get a red brake warning light and the pump will now run continuosly until it burns out. ... hydraulic pressure to the brake system and "no"red warning lights. .... Fog Lights, PassGas, Toyota Prius General Discussion, 4, 10-13-2005 09:12 AM ... 11-13-2015 10:01 PM by Tim Lee.

Alarm with Brake Light, ABS, VSC and amber warning lights ' PriusChat

priuschat.com > ... > Gen 2 Prius Care, Maintenance and Troubleshooting

Jul 26, 2005 - Later that same day - I started getting an alarm - as soon... ... Gen 2 (2004-2009) Toyota Prius Forums > Gen 2 Prius Care, ... Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by NorthStar, Jul 26, 2005. ... I am getting the red BRAKE LIGHT, the amber waming symbol, ABS, and ... VSC, ABS, (!) and emergency brake light on
Feb 5, 2010
Brake, Brake warning, ABS, VSC appear
Oct 5, 2008
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toyota prius This is the most useful thing I think, to get manual so you can do it yourself anytime ! Check it out

C0550 is the code for the ABS module. It is on the frame under the vehicle around the drivers door area. It is a module with all the brake lines coming from it. Reset the trouble codes and see if the problem returns. If it does, the module is not serviceable and will need to be replaced.

Cavity/ Fuse /Circuits
1/ 20 Amp Yellow/ Left High Beam Headlight
2/ 20 Amp Yellow/ Right High Beam Headlight
3/ 15 Amp Dk. Blue/ Adjustable Pedal
4/ 20 Amp Yellow/ Horn
5/ 25 Amp Clear/ Headlamp Washer - If Equipped
6/ 15 Amp Dk. Blue/ Front Control Module (FCM)
7/ 20 Amp Yellow/ Fog Lamp
8/ 15 Amp Dk. Blue/ Park Lamp
9/ 15 Amp Dk. Blue/ Non ABS Brakes
10/ 5 Amp Orange/ Starter
11/ 20 Amp Yellow/ Auto Shutdown/Powertrain Control Module (PCM)
12/ - -
13/ - -
14/ 25 Amp Clear/ Powertrain Control Module
15/ 20 Amp Yellow/ Injectors, Ignition Coils
16/ 15 Amp Dk. Blue/ Powertrain Control Module
17/ 30 Amp Pink/ Antilock Brake System (ABS) Valves
18/ 30 Amp Pink/ Windshield Wiper/Washer
19/ 50 Amp Red/ Radiator Fan
20/ 20 Amp Lt. Blue/ Starter
21/ 50 Amp Red/ ABS Pump Motor
22/ 40 Amp Green/ Radiator Fan High/Low
23/ 50 Amp Red/ High Intensity Lighting
24/ - -
25/ 30 Amp Pink/ Lighting Left High Beam/Right Low Beam
26/ 20 Amp Lt. Blue/ Transmission
27/ 30 Amp Pink/ Lighting Left Low Beam/Right High Beam
if this helps please rate 4 thumbs up.

Below is a listing of which fuse corresponds with which circuit:

1 - 10 Amp - Transmission Controller, Gauges, Autostick
2 - 10 Amp - Right High Beam Headlight
3 - 10 Amp - Left High Beam Headlight
4 - 10 Amp - Radio, CD Player
5 - 10 Amp - Washer Motor
6 - 15 Amp - Power Outlet
7 - 20 Amp - Tail, License, Parking, Illumination Lights, Instrument Cluster
8 - 10 Amp - Airbag
9 - 10 Amp - Turn Signal Lights, Turn Signal/Hazard Indicator
10 - 15 Amp - Right Low Beam
11 - 20 Amp - High Beam Relay, High Beam Indicator, High Beam Switch
12 - 15 Amp - Left Low Beam Headlight
13 - 10 Amp - Fuel Pump Relay, Power Train Control Module
14 - 10 Amp - Cluster, Day/Night Mirror,Sunroof, Overhead Console, Garage Door Opener, Body Control Module
15 - 10 Amp - Daytime Running Light Module (Canada)
16 - 20 Amp - Fog Light Indicator
17 - 10 Amp - ABS Control, Back Up Lights, Daytime Running Lights, A/C Heater Control Cavity Fuse Circuits
18 - 20 Amp - Power Amplifier, Horn
19 - 15 Amp - Overhead Console, Garage Door Opener, Trunk, Overhead, Rear Reading, and Visor Vanity Lights, Trunk Release Solenoid, Power Mirrors, Power Door Locks, Body Control Module, Aspirator Motor
20 - 20 Amp - Brake Lights
21 - 10 Amp - Leak Detection Pump, Low Rad Relay, High Rad Relay, A/C Clutch Relay
22 - 10 Amp - Airbag
23 - 30 Amp - Blower Motor, ATC Power Module
24 - 20 Amp - Power Window Motors
25 - 20 Amp - Power Door Lock Motors, Power Seats

Fuse #8, #18 and #22.

Below is a listing of which fuse corresponds with which circuit:

1 - 10 Amp - Transmission Controller, Gauges, Autostick
2 - 10 Amp - Right High Beam Headlight
3 - 10 Amp - Left High Beam Headlight
4 - 10 Amp - Radio, CD Player
5 - 10 Amp - Washer Motor
6 - 15 Amp - Power Outlet
7 - 20 Amp - Tail, License, Parking, Illumination Lights, Instrument Cluster
8 - 10 Amp - Airbag
9 - 10 Amp - Turn Signal Lights, Turn Signal/Hazard Indicator
10 - 15 Amp - Right Low Beam
11 - 20 Amp - High Beam Relay, High Beam Indicator, High Beam Switch
12 - 15 Amp - Left Low Beam Headlight
13 - 10 Amp - Fuel Pump Relay, Power Train Control Module
14 - 10 Amp - Cluster, Day/Night Mirror,Sunroof, Overhead Console, Garage Door Opener, Body Control Module
15 - 10 Amp - Daytime Running Light Module (Canada)
16 - 20 Amp - Fog Light Indicator
17 - 10 Amp - ABS Control, Back Up Lights, Daytime Running Lights, A/C Heater Control Cavity Fuse Circuits
18 - 20 Amp - Power Amplifier, Horn
19 - 15 Amp - Overhead Console, Garage Door Opener, Trunk, Overhead, Rear Reading, and Visor Vanity Lights, Trunk Release Solenoid, Power Mirrors, Power Door Locks, Body Control Module, Aspirator Motor
20 - 20 Amp - Brake Lights
21 - 10 Amp - Leak Detection Pump, Low Rad Relay, High Rad Relay, A/C Clutch Relay
22 - 10 Amp - Airbag
23 - 30 Amp - Blower Motor, ATC Power Module
24 - 20 Amp - Power Window Motors
25 - 20 Amp - Power Door Lock Motors, Power Seats

It's both mechanical and electrical. See an expert to handle this.

There is a chance that your ABS module is going out, or has gone out, although that doesn't explain the rough idle problem. I had the same thing happen on my '01 Tahoe, and it's a known problem with ABS units. Repair at dealer is over $1200.00. Repair yourself with a rebuilt module is $150.00+shipping and a little elbow grease. Get on EBay, search for ABS module repair, and there is a company in Russia, Iowa who will rebuild the one you have, and warrant it for 5 years (GM won't do that with their $1200 repair.).

The rough idle I bet is coincidental and not related.

it should be number 42


MKIV FUSE LIST
1. Washer nozzle heaters, glove compartment light, memory seat control module (10A).
2. Turn signal lights (10A).
3. Fog light relay, instrument panel light dimmer switch (5A).
4. License plate light (5A).
5. Comfort system, cruise control, Climatronic, A/C, heated seat control modules, automatic day/night interior mirror, control module for multi-function steering wheel, control unit in steering wheel (7.5A).
6. Central locking system (5A).
7. Back-up lights, speedometer vehicle speed sensor (VSS) (10A).
8. Open
9. Anti-lock brake system (ABS) (5A).
10. Engine control module (ECM): gasoline engine (10A); diesel engine, Model Year 2000 > (5A).
11. Instrument cluster, shift lock solenoid (5A).
12. Data Link Connector (DLC) power supply (7.5A).
13. Brake tail lights (10A).
14. Interior lights, central locking system (10A).
15. Instrument cluster, transmission control module (TCM) (5A).
16. A/C clutch, after-run coolant pump (10A).
17. Open.
18. Headlight high beam, right (10A).
19. Headlight high beam, left (10A).
20. Headlight low beam, right (15A).
21. Headlight low beam, left (15A).
22. Parking lights right, side marker right (5A).
23. Parking lights left, side marker left (5A).
24. Windshield and rear window washer pump, windshield wiper motor (20A).
25. Fresh air blower, Climatronic, A/C (25A).
26. Rear window defogger (25A).
27. Motor for rear windshield wiper (15A).
28. Fuel pump (FP) (15A).
29. Engine control module (ECM) gasoline engine (15A); diesel engine (10A).
30. Power sunroof control module (20A).
31. Transmission control module (TCM) (20A).
32. Injectors: gasoline engine (10A); diesel engine (15A).
33. Headlight washer system (20A).
34. Engine control elements (10A).
35. 12 V power outlet (in luggage compartment) (30A).
36. Fog lights (15A).
37. Terminal (86S) on radio, Instrument cluster (10A).
38. Central locking system (with power windows), luggage compartment light, remote/fuel tank door, motor to unlock rear lid (15A).
39. Emergency flashers (15A).
40. Dual tone horn (20A).
41. Cigarette lighter (15A).
42. Radio (25A).
43. Engine control elements (10A).
44. Heated seats (15A).
Fuse arangements in fuse bracket/battery:
S162. Glow plugs (coolant) (50A).
S163. Fuel pump (FP) relay/glow plug relay (50A).
S164. Coolant fan control (FC) control module/coolant fan (40A).
S176. Relays panel interior (110A).
S177. Generator (GEN) (90 Amp.) (110A).
Generator (GEN) (120 Amp.) (150A).
S178. ABS (hydraulic pump) (30A).
S179. ABS (30A).
S180. Coolant fan (30A).