Eduardo Escobar

Hi there, i'm new to this forum.

I have a 2001 Honda Civic 1.7L LX, manual transmission, D17A1 engine.

Some weeks ago the check engine indicator of my car popped up, used a ELM327 scanner interface which told me there was the following fault error: P0132 - O2 Sensor Circuit High Voltage Bank 1 Sensor 1.

I researched a little and found out it was related to the Upstream O2 Sensor (located in the exhaust manifold, before the catalytic converter). Went to the autoparts shop and bought a new one - yes, i have to admit that i had to perform tests on the old sensor to find out whether it was damaged or not... Anyway, i replaced the sensor, cleared fault errors in ECU/ECM, made a new scan and the following fault code was thrown: P0135 - O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 1, check engine indicator is still there, so far, although it goes off eventually while driving.

I unplugged the sensor and made some voltage tests on the car's connector's terminals (not the sensor's connector). According to the following diagram:


Test 1: Battery's negative terminal against connector's ~ +12V terminal, result: tester displays 12.77V.
Test 2: Battery's positive terminal against connector's GND terminal, result: tester displays 0V (it blinks -0.01V, -0.02V).

So i'm guessing there is a problem with the connector's GND terminal / cable, however i'm stuck at this point. What test should i perform now? I've read somewhere that this cable comes from the car's ECU/ECM, but i'm not sure about messing with that one. I'm not a tech guy, i do have some electricity knowledge and i thought it was gonna be enough to fix it by myself.

If someone can enlighten me i'd appreciate it a lot. Thanks!