dewmanshu

iTrader: (4)

Wait...you are getting heater codes on Sensor #2's as well? That's rare. Headers will certainly cause these codes on Sensor #1's, but post-cat sensors? That's pretty rare IMO. I am ALL ABOUT turning codes off, , but those B1S2 and B2S2 codes are odd. When did you do the Bassani's? Are they coated? They aren't long tubes, I find it hard to believe those rear sensors are not getting hot enough (rear sensors have hotter heaters, why everyone gets the rear vette sensors). Cold start up is when it does the check on them. I'd suggest swapping them around but you have all of them banging you with codes. Ugh. Has Justin given you any feedback?

Steve-O-08

iTrader: (5)

Yeah I am getting codes for all four sensors. I've had the Bassani's in before the 370 swap and never had an issue. Thinking about just turning off the codes.

The Bassani's are Mid's they are coated too. Still running factory cats.

I looked up the triggers for the codes and they set if low or high voltage is detected in the heater circuit on start up. I can clear the codes and drive around without them coming back for a few days before they set again. Thought it was a fuse or relay or ground and everything checks out.

X_Racing1

Steve, What did you find on this? i am having this same issue i replaced all 4 and still have it and i still have everthing stock except a CAI and a flowmaster no headers or any thing? about to go crazy.

Steve-O-08

iTrader: (5)

I never ended up finding out what the issue was. The codes are disabled...

roughneck427

iTrader: (12)

Did you check the O2 A and O2 B fuses in the under the hood fuse block??

Rafal Styczen

I have the same problem. Did you solve it?

I swapped LS LM7 into F150 1977. (engine, fuel senders and EVAP vents into steel tank, EVAP, lines, exhaust with cats, BCM, etc)

Everything works great. The truck runs superb. Enters Closed-Loop.

I am having problems with Oxygen sensors. When the engine is cold, on the first start only I am getting all 4 oxygen sensor heater circuit malfunction errors in pending codes (P0135, P0141, P0155, P0161).
It happens only at the first start. On the second start they do not come up. However, the system I/M readiness is not checking Catalyst and EVAP. I believe this is due to Heater Malfunction as above and not getting O2 Heater Ready (however they sometimes get ready when I drive and exhaust gasses heat-up).

I did almost everything I've seen on forums:

1. Changed all four O2 sensors
2. Checked the continuity of the circuits from ECU to sensors
3. Checked the heater power turning by ECU with a bulb instead of the sensor. (Going on after crank and flashing, however, as I said, only on first cold start. Even then I go only for few seconds. Second start is not turning heating on).
4. Checked grounds, from cylinder battery to ECU grounds on ECU connector (0-1 ohm).
5. Disconnected battery for more than 45 minutes, to zero-out any memory in ECU
6. Checked sensors heater resistance (13 Ohm). Power on sensors 12V

What can be wrong? Please help. I got out of ideas.

There is one chance, that all new sensors are wrong or bad. Resistance is good and I got the same all 4 codes with old junkyard sensors.