CHECK A 5-VOLT SUPPLY CIRCUIT FOR VOLTAGE

The purpose of the following procedure is to demonstrate how to check the voltage of a 5-Volt supply circuit with a voltmeter.

NOTE: The circuit shown is an example, and is intended for demonstrational purpose only.

The following are circuit tests covered in this procedure:

NOTE:
Perform the following test using a known good multimeter.

Below is a list of possible causes that could be related to a No Voltage condition.

Possible Causes
OPEN CIRCUIT (CHAFED, PIERCED, PINCHED OR BROKEN WIRES)
OPEN IN-LINE CONNECTOR (BENT, PUSHED OUT OR CORRODED TERMINALS)
ELECTRONIC CONTROL MODULE (5-VOLT SUPPLY OUTPUT)

1. TESTING A 5-VOLT SUPPLY CIRCUIT FOR VOLTAGE

1.	Turn the ignition off.

2.	Disconnect the sensor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

3.	Turn the ignition on.

4.	Set the multimeter to measure DC voltage.

5.	Connect the negative lead of the multimeter to a known good ground.

6.	With the positive lead of the multimeter, carefully probe the 5-volt supply circuit.

Is the voltage between 4.7 and 5.2 volts?

Yes

Check the 5-volt supply circuit for an open or short to ground. For further assistance, perform the appropriate Sensor Reference Voltage DTC diagnostic procedure.

2. TESTING A 5-VOLT SUPPLY CIRCUIT AND SENSOR GROUND CIRCUIT

1.	With the multimeter set to measure DC voltage.

2.	Move the negative lead of the multimeter to carefully probe the sensor ground or sensor return circuit in the harness connector.

3.	With the positive lead of the multimeter, carefully probe the 5-volt supply circuit.

Is the voltage between 4.7 and 5.2 volts?

Yes

At this time the 5-volt supply and sensor ground circuit are working properly. Continue to measure the voltage between the wires, wiggle the wire harness and connectors while checking for an intermittent condition.
Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors where the open could occur intermittently.
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related wire harness connectors.
Perform any Technical Service Bulletins (TSBs) that may apply.

Repair the open or excessive resistance in the Sensor Ground (Sensor Return) circuit.