DTC P0133: O2 Sensor 1/1 Slow Response & DTC P0139: O2 Sensor 1/2 Slow Response: Testing

NOTE: If one of the O2 sensors signal or return circuits are shorted to ground or voltage, all the other O2 sensor voltage readings will be affected. It is important to perform the diagnostics on the O2 sensor that set the DTC. After the repairs have been made, verify proper O2 sensor operation. If all the O2 sensor voltage readings have not returned to normal, follow the diagnostic procedure for the remaining O2 sensors. Before proceeding, check for contaminants that may have damaged HO2S such as contaminated fuel, unapproved silicone, oil and coolant.

Ignition on, engine not running. With the DRBIII® scan tool, read DTCs and record the related freeze frame data. Is the Good Trip counter displayed and equal to zero? If yes, go to next step. If no, see INTERMITTENT CONDITION under SELF-DIAGNOSTIC SYSTEM.
Start the engine. Inspect the exhaust for leaks between the engine and the related O2 sensor. Are there any exhaust leaks? If yes, repair or replace the leaking exhaust parts as necessary. If no, go to next step.
Turn the ignition off. Disconnect the O2 sensor harness connector. Ignition on, engine not running. Measure the voltage on the O2 signal circuit in the O2 sensor harness connector. Is the voltage approximately 5.0 volts? If yes, go to next step. If no, check the O2 signal circuit for damage, short to ground, open, or short to voltage. If OK, replace and program the PCM. See PROGRAMMING .
Turn the ignition off. Disconnect the O2 sensor harness connector. Ignition on, engine not running. Measure the voltage on the O2 return circuit in the O2 sensor harness connector. Is the voltage at 2.5 volts? If yes, check the O2 return circuit for damage, short to ground, open, or short to voltage. If OK, replace and program the PCM. See PROGRAMMING . If no, go to next step.
If no other possible causes are remaining, replace O2 sensor.