DTC P0135:00, P0155:00 [MZI-3.7]: Notes

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

DETECTION CONDITION & POSSIBLE CAUSE

DTC P0135:00 DTC P0155:00	P0135:00: A/F sensor (RH) heater circuit P0155:00: A/F sensor (LH) heater circuit
DETECTION CONDITION	P0135:00 indicates A/F sensor (RH) heater circuit. P0155:00 indicates A/F sensor (LH) heater circuit During testing the HO2S heaters are checked for open and short circuits and excessive current draw. The test fails when the current draw exceeds the calibrated limit or an open or short circuit is detected.
POSSIBLE CAUSE	Open circuit between main relay terminal A and A/F sensor (RH/LH) terminal 2 Damaged ENGINE fuse Short to ground between A/F sensor (RH/LH) terminal 2 and ENGINE fuse P0135:00: Open circuit between PCM terminal 2J and A/F sensor (RH) terminal 4 P0155:00: Open circuit between PCM terminal 2E and A/F sensor (LH) terminal 4 P0135:00. Short to power supply between PCM terminal 2J and A/F sensor (RH) terminal 4 P0155:00. Short to power supply between PCM terminal 2E and A/F sensor (LH) terminal 4 A/F sensor heater control signal circuit short to each other A/F sensor heater malfunction Water in the wiring harness connector Low battery voltage Corrosion or incorrect wiring harness connections PCM malfunction
Courtesy of MAZDA MOTORS CORP.