Smog testing is right around the corner. Had a CEL recently for Evap. Replaced the Evap cleared the code and all was well. Several months later another CEL. Scanned for codes and all 02 sensors were triggered. 12v to all sensors. Remaining 3 wires to O2’s ohms out to ground, telling me there’s no break in the circuit. Replaced all O2 sensors, same issue. Bought a blue driver scanner, all O2 sensors seems to be reading fine. Did a complete drive cycle and passed all emissions readiness on the scan tool then shortly after O2 light comes on again. I’m like WTF! So I returned the tune to stock and noticed with stock tune it was only registering the front O2 sensors on the blue driver scan tool. Anyone can confirm if stock tune only reads the front O2 sensors? It reads all 4 when I load 93 Brenspeed tune just fine.
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View attachment 93426