ECU Power Source Circuit

METER: METER / GAUGE SYSTEM: ECU Power Source Circuit

ECU Power Source Circuit

DESCRIPTION

Confirm that the speedometer, the tachometer, the fuel receiver gauge and SFI system are normal, then check this circuit.
Refer to SFI system for 1GR-FE DTC Check / Clear or 2UZ-FE DTC Check / Clear.

HINT: If this circuit has a malfunction, average fuel consumption display/instantaneous fuel consumption display/possible running distance display cannot be displayed correctly.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. INSPECT COMBINATION METER ASSEMBLY (TAU-B)

(a) Remove the combination meter assembly.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

2. INSPECT COMBINATION METER ASSEMBLY (TAU-G)
(a) Check the input signal waveform.

(1) Remove the combination meter assembly.
(2) Connect the oscilloscope to terminal C9-8 (TAU-G INPUT) and body ground.
(3) Start the engine.

(4) Check the signal waveform according to the condition(s) in the table below.

HINT: As the engine speed goes higher, the frequency becomes shorter.

NG -- CHECK HARNESS AND CONNECTOR (ECM - COMBINATION METER)
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (ECM - COMBINATION METER)

(a) Disconnect the E6 and C9 connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (LCD DISPLAY)
(a) Check the LCD display appears.
OK:
LCD display appears.

NG -- GO TO AIR CONDITIONING SYSTEM
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - COMBINATION METER)
(a) Disconnect the A17 and C9 connectors.

(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE COMBINATION METER ASSEMBLY