Parking Assist (Sonar Sensors & Rear Camera) Wiring — Toyota Prius

ToyotaPrius2009–2015Body & AccessoriesUpdated 2026-10-10

The Parking Assist ECU powers the rear ultrasonic (sonar) sensors, listens for obstacles and beeps, and sends the rear camera picture to the navigation screen. The two rear sensors are wired in a chain: the ECU feeds the left sensor, and the left sensor passes power, ground and signal on to the right sensor.

Pinout — pin number & wire colour

Parking Assist ECU connectors: L64 = (A), L65 = (B), L106 = (C)

Pin	Name	Wire colour	What it does
Connector (A)
11	CV−	B Black	Rear camera video − (shielded cable).
12	CV+	R Red	Rear camera video + (shielded cable).
13	CGND	—	Camera cable shield / ground.
14	CB+	W White	Power to the rear camera.
19	CSB3	G Green	Power to the rear sonar sensors (LH sensor pin 1).
20	CSG3	R Red	Ground for the rear sonar sensors (LH sensor pin 5).
21	LIN3	GR Gray	Signal / data line of the rear sonar sensors (LH sensor pin 3).
Connector (B)
1	+B	SB Sky blue	Battery power, always on (15A RAD NO.1 fuse).
3	GND1	W-B	Ground.
7	IG	B Black	Power with key ON (10A ECU-IG NO.2 fuse).
8	ACC	GR Gray	Power with key in ACC (10A ECU-ACC fuse).
11	ISSW	L Blue	Sonar ON/OFF switch (switch goes to ground on brown wire).
14	HG1	Y Yellow	Height sensor line (front height control sensor RH).
15	HB+	P Pink	Height sensor line (headlight levelling ECU).
16	HB1	P Pink	Height sensor line (front height control sensor RH).
21	CANL	BR Brown	CAN low — data to other computers.
22	CANH	Y Yellow	CAN high — data to other computers.
23	TX+	LG Light green	Picture / data to the navigation screen (TX1+, pin 9).
24	TX−	P Pink	Picture / data to the navigation screen (TX1−, pin 10).
26	HO1	SB Sky blue	Height sensor line (headlight levelling ECU).
27	HGND	Y Yellow	Height sensor ground (headlight levelling ECU).
28	HI1	L Blue	Height sensor line (front height control sensor RH).
Connector (C)
1	GVIF	B Black	Screen link ground / shield (GVIF, pin 1).

1. Power, ground and sonar switch

Pin 1 (B), sky-blue wire: battery power all the time from the 15A RAD NO.1 fuse.
Pin 8 (B), gray wire: power when the key is in ACC (10A ECU-ACC fuse).
Pin 7 (B), black wire: power when the key is ON (10A ECU-IG NO.2 fuse).
Pin 11 (B), blue wire: the sonar ON/OFF switch. Pressing it connects the wire to ground (brown wire).
Pin 3 (B), white-black wire: main ground of the ECU.

2. Rear sonar sensors and rear camera

The ECU sends power (green, pin 19 A), ground (red, pin 20 A) and a signal line (gray, pin 21 A) to the LEFT rear sensor.
The left sensor passes them on to the RIGHT sensor: yellow = power, brown = ground, blue = signal. If the left sensor or its plug fails, the right one stops too.
The rear camera gets power on CB+ (white) and sends its picture back on CV+ (red) and CV− (black) inside a shielded cable (CGND).

3. CAN data and the navigation screen

CANH (yellow, pin 22 B) and CANL (brown, pin 21 B) connect the ECU to the CAN bus — it gets speed, gear and steering angle from other computers.
TX+ (light green), TX− (pink) and GVIF (black) carry the camera picture and guide lines to the navigation screen.
The integration relay sends a reverse (REV) signal to the screen on a pink wire so it switches to the camera view.

🧰 Tools you need

Digital multimeter
OBD2 scanner (ELM327 or better)
12 V test light
Back-probe pins / jumper wires

Wire colour codes

Wires in the diagrams are drawn in their real colours. Manuals write colours as short letters:

SB Sky blue

B Black

GR Gray

L Blue

R Red

W White

Y Yellow

P Pink

G Green

BR Brown

LG Light green

Two letters with a dash, like W-B, means a white wire with a black stripe.

Common problems & quick checks

Problem	Likely cause	What to check
No beep at all, system dead	Fuse blown, no power or ground, or switch OFF	Check fuses RAD NO.1, ECU-ACC, ECU-IG NO.2. Key ON: 12 V on pins 1, 7, 8 (B). Check ground on pin 3 (B). Press the sonar switch.
Both rear sensors not working	Problem on the green / red / gray wires or the LEFT sensor	Check the plug of the left sensor in the bumper (water / rust). Check wires to pins 19, 20, 21 (A).
Only the right sensor not working	Right sensor faulty, or yellow / brown / blue wire between the sensors	Swap left and right sensors: if the fault moves, replace that sensor. Check the wires between them.
No camera picture in reverse	No camera power, broken video wire, or screen link fault	In reverse, check power on CB+ (white). Check CV+ / CV− wires and the shield. Check TX+ / TX− to the screen.
Many warning messages / no guide lines	CAN data missing (speed, gear, steering angle)	Scan for U-codes. Check CANH (yellow) and CANL (brown) on pins 22 / 21 (B).

Related trouble codes

Networkhigh

U0001 — High Speed CAN Communication Bus

A module found a problem on the high-speed CAN data wires.

Networkmedium

U0140 — Lost Communication With Body Control Module

The body computer (lights, locks, wipers, chimes) is not talking on the data wires.

Powertrainmedium

P0562 — System Voltage Low

The computer sees battery / charging voltage below normal.

This is a simplified drawing for learning. Pin numbers and colours can change by model and year — check the service manual for your exact car before repairing.