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2003 Pontiac Grand Am P0135 O2 Sensor Heater Bank 1 Sensor 1 Fault Diagnosis and Fix

Model: 2003 Pontiac Grand Am Fault Code: P0135 Posted: 2014-09-26 13:13

2003 Pontiac Grand Am GT 3.4L V6 The Service Engine Soon (SES) light has come on, and after scanning the vehicle, I received a P0135 diagnostic code: "Oxygen Sensor Heater Circuit Bank 1 Sensor 1". What is the correct procedure to diagnose and fix this issue? I've checked basic components but am unsure if the sensor itself or wiring is at fault.

Related fault codes
P0135
Comments (4)
Anonymous 2014-09-26 14:04

Start by checking the fuses in the underhood fuse box—specifically fuse #47. Next, verify that the oxygen sensor is receiving 12 volts with the key off (KOEO) using the brown wire. Then test the resistance of the O2 sensor with a multimeter. Share your findings so we can proceed to check O2 sensor voltage readings and ensure proper connectivity of the B1S1 wire to the Powertrain Control Module (PCM).

Anonymous 2014-09-27 15:37

The voltage reading is correct, and the resistance measurement shows 126 ohms.

Anonymous 2014-09-27 15:55

A reading of 126 ohms suggests the oxygen sensor may be faulty—this value falls outside the normal range for a healthy sensor, indicating it might need replacement.

Anonymous 2014-09-27 16:20

I've double-checked the readings multiple times, and I confirm that the resistance is indeed 126 ohms. This aligns with my conclusion that the O2 sensor is defective.