Test Procedure

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK 

Start diagnosis

-- Connect the scan tool.

-- Start the engine and allow it to idle.

-- Using the scan tool, Check the engine speed:

Diagnostic text		Specified value
Engine revolutions per minute (RPM)		Idle speed

-- Switch ignition OFF.

If the specified value was obtained:

-- Fault may be intermittent. Check harness connectors and terminals, for loose connections or poor terminal contact.

-- Check the wiring connection for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

If the specified value was Not obtained:

-- Disconnect the Engine Speed Sensor -G28- electrical harness connector.

-- Switch the ignition on.

-- Using a multimeter, Check the Engine Speed Sensor -G28- electrical harness connector terminals 1 to 3 for voltage.

Specified value: about 5.0 V

-- Switch the ignition off.

Continue test according to the following table:

Value	Cause	Test
If the specified value was not obtained:	Open or shorted circuit	Checking Wiring
If the specified value was obtained:	Check reference signal circuit	Checking Activation