Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter

The stereo component amplifier assembly receives a vehicle speed signal from the combination meter assembly to control the ASL function.

HINT:

• A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter assembly. The signal is changed to a pulse signal at the transistor in the combination meter assembly. Each ECU controls the respective systems based on the pulse signal.
• If a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems in the diagram below will not operate normally.

1. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

NG

GO TO METER / GAUGE SYSTEM

OK

1. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - COMBINATION METER ASSEMBLY)

(a) Disconnect the N11 stereo component amplifier assembly connector.

(b) Disconnect the F14 combination meter assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

1. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - NO. 4 JUNCTION BLOCK)

(a) Disconnect the N11 stereo component amplifier assembly connector.

(b) Disconnect the A4 No. 4 junction block connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 4 JUNCTION BLOCK)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - NO. 4 JUNCTION BLOCK)