Testing Procedure

O2 Signal -  Connect DVOM between left cylinder bank ME-SFI control module connector 1 terminals No. 40 and 41 (socket box terminals No. 40 and 41). Start engine and idle. Allow engine to idle for at least 2 minutes after engine coolant temperature reaches more than 176°F (80°C). Voltage should fluctuate by more than 0.3 volts between -0.2 volts and one volt. If voltage is okay, test is complete. If voltage is not okay, possible causes are left O2 sensor (before TWC) heater failure, wiring harness failure or defective left O2 sensor (before TWC - G3/3). To check left O2 sensor (before TWC) heater failure, go to DTC P0155: O2 SENSOR HEATING OF LEFT O2 SENSOR UPSTREAM TWC (G3/3)  .