ECM supplies approximately .45 volt between ECM terminals D7 and D6. If voltage is measured with a 10-megohm DVOM, reading may be as low as .32 volt. The O2 sensor produces a varying voltage as engine reaches normal operating temperature. Voltage varies between .1-1.0 volt.

The O2 sensor will not produce voltage until sensor reaches 600°F (316°C). When sensor is less than this temperature, open loop condition exists.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Code 13 sets if the following conditions are present for 60 seconds:
- Engine temperature is greater than 158°F (70°C).
- Engine has been running for at least 50 seconds after start.
- O2 signal voltage is steady between .347-.547 volt.
- Throttle angle is greater than 5 percent.
If condition for Code 13 exist, system will not go into closed Loop.
This test determines Whether O2 sensor, ECM and/or wiring is faulty.
Use only high-impedance DVOM when performing this test. This checks continuity of terminals D6 and D7. If D6 is open, ECM voltage on D7 will be greater than .6 volt (600 mV).

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Code 13, O2 Sensor CKT/Open CKT (VIN 6)

Use the Manual With the Right Hardware

When to See a Mechanic

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