Test Description

WARNING: This page is about a different car, the 1995 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Test numbers refer to numbers on diagnostic chart.

This tests if problem still exists. Vehicle cannot enter "closed loop" mode if oxygen sensor circuit is open. Code indicates an open in O2 sensor circuit (steady .35-.55 volt).
Determines if oxygen sensor, wiring or control module is at fault. If wiring is good, grounding oxygen sensor wire will cause .45 volt reference supplied by control module to pull low.
This tests oxygen sensor circuit wiring. Use only a high impedance (10-megohm minimum) digital voltmeter.

Fig 1: Code 13 Schematic (Corvette) Open Oxygen Sensor Circuit

Fig 2: Code 13 Diagnostic Flow Chart (Corvette) Open Oxygen Sensor Circuit