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P0135 O2 Sensor Fault Diagnosis for 2004 Honda Civic LX with 1.7L 4-Cylinder

Model: 2004 Honda Civic Fault Code: P0135 Posted: 2011-12-01 19:46

I own a 2004 Honda Civic LX with a 1.7L 4-cylinder engine. I recently replaced the upstream oxygen sensor (Bank 1, Sensor 1) with a Bosch OEM-compatible part. Despite proper wiring and connections, the check engine light remains on and the P0135 diagnostic code persists. After verifying all electrical connections, I'm seeking advice on potential causes beyond the sensor itself. Could it be related to a faulty fuse, wiring harness, or another component? Any guidance on troubleshooting this issue would be greatly appreciated.

Related fault codes

P0135

Comments (8)

Anonymous 2011-12-02 06:07

A common misconception — using a Bosch part isn't automatically wrong. Compatibility is key. In my experience, the part must match Honda's specifications. However, if the P0135 code persists after installation, it's important to rule out other factors such as blown fuses or wiring issues.

Anonymous 2011-12-02 19:27

The Bosch sensor I installed was fully compatible with my 2004 Honda Civic. After replacing the upstream O2 sensor, I noticed the check engine light stayed on. Upon further inspection, I discovered a blown fuse in the vehicle's electrical system — specifically the power supply for the ECU-related circuits. Replacing that fuse and resetting the code resolved the issue immediately.

Anonymous 2011-12-03 05:39

Great to hear your issue was resolved! This confirms that even after proper sensor replacement, other components like fuses or wiring can be the root cause of P0135 codes in Honda Civics.

Anonymous 2012-09-05 15:41

I'm currently diagnosing a similar P0135 code on a 2007 Honda Accord. Could you please share how to locate the relevant fuse? Should I replace the sensor first, or check for blown fuses before proceeding with any repairs?

Anonymous 2012-09-29 12:29

Hi, I have a 1999 Honda Civic EX and recently noticed my check engine light is on. I replaced the upstream O2 sensor myself using a Bosch part from Advanced Auto Parts. After driving about 100 miles, the light remains on. The car runs smoothly with no noticeable performance issues — including power windows, which have never worked since I bought the car in 2005. I'm primarily concerned about clearing this code to pass inspection. I've read that a blown fuse might be responsible. Can someone explain how to troubleshoot and fix the fuse? My previous O2 sensor was replaced two years ago, so I suspect it may not be the issue anymore. I'd like to attempt the repair myself to avoid high mechanic fees. One observation: when I turn the key to ignition (without starting), the check engine light turns on, then after about 2 seconds there's a distinct click sound from the driver’s side, and the light flashes once before returning to solid on. Any insight would be helpful. Thanks! — Prashant

Anonymous 2013-08-18 23:31

The Bosch sensor was fully compatible with my vehicle. The issue wasn't the part itself — it turned out a blown fuse in the ECU power circuit was causing intermittent signal issues. After replacing that fuse and resetting the code, the P0135 error cleared completely.

Anonymous 2016-01-20 12:50

Thanks for sharing! In your case, which specific fuse did you replace? I'm experiencing the same P0135 issue and would like to know exactly where to look — especially since the code persists even after sensor replacement.

Anonymous 2016-01-21 07:51

All fuses and their locations are typically listed in your vehicle's owner’s manual. This is usually found in the glove box or under the hood. For P0135-related issues, focus on fuses related to the engine control module (ECM) or sensor power circuits.