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Lexus ES300 P0135 Fault: How to Locate and Replace Oxygen Sensor Bank 1 Sensor 1

Model: Lexus ES300 Fault Code: P0135 Posted: 2006-01-12 16:23

I own a 1998 Lexus ES300 and my check engine light has come on. After being scanned by a backyard mechanic, the diagnostic code returned is P0135 — Oxygen Sensor Bank 1 Sensor 1. Unfortunately, he was unable to explain where this sensor is located in the vehicle. I would like to replace it myself, but I'm unsure which sensor to remove and replace. Can anyone clarify how many banks and sensors exist on this model, along with their exact locations? I need accurate information to proceed safely and correctly. Thank you for your help.

Related fault codes
P0135
Comments (2)
Anonymous 2006-04-24 18:51

Your post was posted in January. If you're still looking for clarification, Bank 1 Sensor 1 is located on the firewall side of the exhaust manifold. Bank 1 always corresponds to cylinder #1, and Sensor 1 is the first oxygen sensor in that bank. This placement helps ensure accurate readings during engine operation. Trev.

Anonymous 2009-10-21 11:59

The sensor is typically located on the downpipe, closest to the engine. To verify functionality, measure resistance between B+ and HT — it should read 0.8–1.4 ohms at 68°F (20°C) when cold, and 1.8–3.2 ohms when the engine is hot (approximately 1472°F / 800°C). These values are critical for confirming proper sensor operation.