Diagnostic Aids

An intermittent may be caused by rubbed through wire insulation or a wire contacting exhaust. Check for:

• Poor Connection Or Damaged Harness:  Inspect harness for short to ground, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.
• Intermittent Test:  Observe HO2S No. 2 on Tech 1 while moving related connectors and wiring harness with ignition on. If failure is induced, HO2S No. 2 display will change. This may assist in isolating the location of the malfunction.

Fig 1: Code P0137 Schematic (Regal) O2 Sensor NO. 2 (Catalyst Monitor) Low Signal Voltage

Fig 2: Code P0137 Flow Chart (Regal) O2 Sensor NO. 2 (Catalyst Monitor) Low Signal Voltage