2003 V6 Air/Fuel sensor LAF fuse blowing
 

I'm about at wit's end with this one. Have replaced both sensors, checked all the wiring, but the #4 15a fuse keeps blowing. How far back from the connector should I be checking wiring? I am going back as far as I can see.

1. Have you tried unplugging both front and rear air/fuel ratio sensors, and see if the fuse still blows?

2. If the fuse still blows with the two air/fuel ratio sensors unplugged, at Connector C251, test for continuity to body chassis/ground at terminal pin wires #12 (it will be Blu/Wht on the male side, and Wht/Blk on the female side). There should be no continuity.

Leave the connectors for the front and rear A/F ratio sensors unplugged when you test for continuity.

There are actually a few other connectors that I haven't mention yet.

You may already know; but, just to be clear: your V6 has:

• front A/F ratio sensor
• rear A/F ratio sensor

• front secondary heated oxygen sensor
• rear secondary heated oxygen sensor

Under-dash fuse no. 4 protects the A/F ratio relay circuit.

Yep, was aware of that, thanks redbull.

I will check that connector this evening. Could a bad relay cause the fuse to blow?

Yes, a bad relay can cause it.

I will check it as well. It's been frustrating, because I was showing something like 4 codes. Replaced the sensors and fuse and thought I was good to go, but now I'm getting 0135 and 0155 i believe (haven't checked in a while).