Check for damaged harness and terminals including rubber seals :

-. contact resistance, oxidation, corrosion, bent or broken terminals

-. harness connector connection, loose wires etc.

Check for poor connection between ECM and component :

-. backed out terminal, improper mating, broken locks and poor terminal to wire connection

ARE THE WIRES O.K ? & ARE THE CONNECTIONS O.K ?

YES

NO

DTCs listed below are stored in the scan tool

P0501/P0503

Check items with the scan tool and the multimeter

① Wiring harness inspection

② Reference voltage from VSS

③ Waveform from VSS

Specification

Connect the scan tool to the data link connector(DLC)

Fix the vehicle speed and the engine rpm current data

Lift the vehicle up and test the drive at above 3500 rpm.

Check the vehicle speed current data.

IS THE VEHICLE SPEED ABOVE 15 Km/h INDICATED AT ABOVE 3500 RPM OF ENGINE SPEED ?

YES

NO

a.

Go to step 6

Connect the CH A probe to the VSS terminal 3 and check the signal waveform.

IS THERE THE SIGNAL WAVEFORM PROPERLY DISPLAYED ?

YES

NO

a.

Repair open or short in the wire between the VSS terminal 1 and the Fuse No.25(10A)

b.

Repair open or short in the wire between the VSS terminal 2 and the body ground.

c.

Repair open or short in the wire between the VSS terminal 3 and the ECM terminal 49/C230-1.

d.

Replace the fuse if the fuse is broken

e.

Replace the VSS

f.

Go to step 8

WAVEFOAM ANALYSIS

This test should be inspected after depressing the HOLD mode at the vehicle speed of 120 Km/h. The time T becomes shorter and frequency increases when the engine speed is increased. If unstable waveform pattern with non-uniform frequency or no signal, replace the VSS. When the ignition switch is ON, approx. 10V is checked at the VSS terminal 3 through the ECM to the speedometer. Unless there is the voltage at the VSS terminal 3, check the continuity between the speedometer and the ECM terminal 49/C230-1 or the reference voltage at the ECM terminal 49/C230-1 directly.

Check the signal waveform at the ECM terminal 49/C230-1

IS THERE THE SIGNAL WAVEFORM PROPERLY DISPLAYED ?

YES

NO

Disconnect the VSS and then turn the ignition switch ON. measure the voltage at the VSS terminal 1, the terminal 2 and the terminal 3 individually.

IS THERE approx. 12V FOR TERMINAL 1, approx. 0V FOR TERMINAL 2, approx. 10V FOR TERMINAL 3 INDICATED ?

YES

NO

a.

Check for incorrect installation position or sensor losse

b.

Check open or short in the wire between the VSS terminal 3 and the ECM terminal 49/C230-1.

c.

Check open or short in the wire between the VSS terminal 2 and the body ground

d.

Replace the fuse if the fuse is broken.

e.

Go to step 3

Check the voltage at the ECM terminal 49/C230-1 after connecting and turning the ignition switch ON .

IS THERE approx. 10V ?

YES

NO