Vehicle Speed Signal Circuit

VEHICLE SPEED SIGNAL CIRCUIT

Description
^ Unified meter and A/C amp. sends vehicle speed signal to power steering control unit.

Diagnosis Procedure

1.PERFORM UNIFIED METER AND A/C AMP. SELF-DIAGNOSIS

With CONSULT-III
Perform unified meter and A/C amp. self-diagnosis.
Is any error system detected?
YES >> Check the error system.
NO >> GO TO 2.

2.CHECK HARNESS BETWEEN UNIFIED METER AND A/C AMP. AND POWER STEERING CONTROL UNIT
1. Turn the ignition switch OFF.
2. Disconnect unified meter and A/C amp. harness connector.
3. Disconnect power steering control unit harness connector.
4. Check continuity between unified meter and A/C amp. harness connector and power steering control unit harness connector.





Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.

3.CHECK VEHICLE SPEED SIGNAL (1)
1. Turn the ignition switch OFF.
2. Connect unified meter and A/C amp. harness connector.
3. Check unified meter and A/C amp. input/output standard values. Refer to MWI-69, "Reference Value". Combination Meter





Is the inspection result normal?
YES >> GO TO 4.
NO >> Replace unified meter and A/C amp.

4.CHECK VEHICLE SPEED SIGNAL (2)
1. Turn the ignition switch OFF.
2. Connect power steering control unit harness connector.
3. Check signal between power steering control unit harness connector and ground with oscilloscope.
Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Replace power steering control unit.

5.CHECK TERMINALS AND HARNESS CONNECTORS
^ Check power steering control unit pin terminals for damage or loose connection with harness connector.
^ Check unified meter and A/C amp. pin terminals for damage or loose connection with harness connector.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Repair or replace damaged parts.