Instrument Cluster (Combination Meter) Wiring — Simplified

ToyotaPrius2009–2015Meter & Warning LightsUpdated 2026-10-10

The instrument cluster is a small computer. It needs power and ground, it reads a few sensors directly (like fuel level), and it gets speed, rpm and temperature from other computers over the CAN data wires. If any of these fail, gauges or warning lights stop working.

Pinout — pin number & wire colour

Cluster connector: L27

Pin	Name	Wire colour	What it does
3?	TIRE	G Green	Tyre pressure warning (from TPMS ECU).
6?	LVWG	L Blue	Headlight levelling warning.
10	CANH	P Pink	Data wire HIGH — talks to other computers.
11	CANL	W White	Data wire LOW (pair with pin 10).
12?	HOUR	B Black	Clock hour button.
13?	MIN	B Black	Clock minute button.
14	L	B Black	Fuel level signal → fuel sender pin 2 (FS).
15	ES2	W White	Fuel sender ground → sender pin 3 (FE).
16?	IG+	L Blue	Power when key is ON (10A GAUGE fuse).
17?	RST	R Red	Trip reset button.
18?	B	R Red	Battery power all the time (7.5A ECU-B fuse). Keeps clock & trip memory.
20	IG2	G Green	Power when key is ON (7.5A MET fuse) for lights.
21	PBLT	Y Yellow	Passenger seat belt warning.
22	LP	B Black	Security (immobiliser) light.
25	STRG	G Green	Steering wheel display buttons.
26	Turn L	Y Yellow	Left turn arrow (from flasher).
27	Turn R	G Green	Right turn arrow (from flasher).
30?	ES	BR Brown	Ground (negative).
?	EFI	LG Light green	Check-engine light signal (from engine ECU).

? = this number was not clear in the source picture. Check it on the car or in the service manual before testing.

1. The big picture

Fuses power the cluster: ECU-B (red wire at the meter, always on) and GAUGE (blue wire, key ON).
Sensors and buttons are wired straight to the cluster.
The cluster drives the gauges, screen, warning lights and chime.
Speed, rpm and temperature come over the CAN data wires (pink + white) from other computers.

2. Power and ground

Battery → ECU-B 7.5A fuse → yellow wire → joint connector → red wire → pin 18 (B). Always has 12 V, even with key OFF.
Key ON → GAUGE 10A fuse → blue wire → pin 16 (IG+). This wakes the cluster up.
Key ON → MET 7.5A fuse → green wire → pin 20 (IG2). Powers warning lights.
Pin 30 (ES) → brown wire → ground. A loose ground = flickering or dead meter.

3. Fuel gauge circuit

The cluster sends a small voltage out on pin 14 (black wire) to the fuel sender pin 2 (FS).
In the tank, a float moves a variable resistor. More or less fuel = different resistance = different voltage.
The return comes back on the white wire from sender pin 3 (FE) to pin 15 (ES2), which is ground. The CPU reads the voltage and moves the fuel needle.

🧰 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:

R Red

L Blue

G Green

BR Brown

P Pink

W White

B Black

Y Yellow

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
Whole meter dead, car runs	GAUGE fuse blown or bad ground	Check fuse. Key ON: 12 V on pin 16 (blue)? Check pin 30 (brown) to ground.
Clock / trip resets every time	No always-on power	Check ECU-B fuse. Key OFF: 12 V on pin 18 (red)?
Speedometer at zero, other gauges OK	No speed message from ABS	Scan ABS for codes. Check wheel speed sensors and CAN wires (pin 10 pink / 11 white).
Fuel gauge stuck full or empty	Black or white wire broken / shorted, or worn sender	Unplug sender: needle should move to one end. Measure sender resistance (pin 2 to 3).
Many warning lights at once	CAN wire problem or low battery	Check battery voltage. Scan for U-codes. Check pink / white wires.

Related trouble codes

Networkmedium

U0155 — Lost Communication With Instrument Panel Cluster

Another computer in the car stopped getting messages from the meter. The meter has no power, no ground, or is not connected to the data wires.

Networkhigh

U0100 — Lost Communication With ECM/PCM "A"

Other computers can no longer hear the engine computer (ECM).

Networkmedium

U0121 — Lost Communication With ABS Control Module

The ABS computer stopped sending messages on the data wires.

Networkmedium

U0140 — Lost Communication With Body Control Module

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

Powertrainlow

P0460 — Fuel Level Sensor "A" Circuit

The fuel level signal is not what the computer expects.

Powertrainlow

P0462 — Fuel Level Sensor "A" Circuit Low

Fuel level signal voltage is too low — usually the wire is touching ground (short).

Powertrainlow

P0463 — Fuel Level Sensor "A" Circuit High

Fuel level signal voltage is too high — usually a broken wire (open circuit).

Powertrainmedium

P0500 — Vehicle Speed Sensor "A"

The computer is not getting a correct speed signal.

Powertrainhigh

P0520 — Engine Oil Pressure Sensor/Switch Circuit

The oil pressure switch / sensor signal is wrong.

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.