Code No. P0502: Vehicle Speed Signal Low Input <Vehicles with M/T>

OPERATION

A power voltage of 5 V is applied to the vehicle speed sensor terminal from the engine-ECU connector terminal V/S.

FUNCTION

The vehicle speed sensor converts the vehicle speed to the voltage, and then input it into the engine-ECU

TROUBLE JUDGEMENT

Check Conditions

Engine is running
Engine coolant temperature is 80°C or higher
The last fuel injection rate exceeds the specified value.
Engine speed is 2,900 r/min or more.

Judgement Criterion

Vehicle speed is 5 km/h or lower for 2 seconds.

FAIL-SAFE AND BACKUP FUNCTION

The EGR control is stopped (fully closed).

PROBABLE CAUSES

Failed vehicle speed sensor
Open/short circuit or harness damage in vehicle speed sensor circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the speed meter

Q. Is the check result normal?

	Go to Step 2.

	Check the speed meter (Refer to GROUP 54A -Combination Meter - On-vehicle Service - Speedometer Check ).

STEP 2. M.U.T.-III data list

Refer to Data list reference table .

Item 4: Vehicle speed sensor

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Go to Step 3.

STEP 3. Check harness between engine-ECU connector terminal V/S and vehicle speed sensor connector terminal.

Check output line for open circuit and damage.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 4. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace the engine-ECU.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).