No closed loop

[rubrhammer]

I'm still struggling with this 2002 LQ4 that won't go closed loop. I've used a different PCM, new O2 sensors and checked the wiring 3 times. The scan tool is showing activity for 4 O2 sensors when only 2 are installed. Sensor voltage ranges from .435v to .460v on all 4 lines on the scan tool. The activity is rapid changes as though it was in closed loop. It's very rapid. Scan tool then shows codes for no activity on them. Sensors are grounded to cylinder head and have 13.5v on the pink wire.
LTFT and STFT are flat line in live data on scan tool. LTFT and STFT are enabled in the calibration.
This is a Canadian VIN PCM for a 5.3 with 6.0 fuel tables imported. The harness was from the same vehicle. O2 sensor wires were not removed from PCM and were shortened one at a time. O2 sensors are for a Canadian 5.3.
I'm totally baffled. Any help would be greatly appreciated!!!!

[2xLS1]

I'm still struggling with this 2002 LQ4 that won't go closed loop. I've used a different PCM, new O2 sensors and checked the wiring 3 times. The scan tool is showing activity for 4 O2 sensors when only 2 are installed. Sensor voltage ranges from .435v to .460v on all 4 lines on the scan tool. The activity is rapid changes as though it was in closed loop. It's very rapid. Scan tool then shows codes for no activity on them. Sensors are grounded to cylinder head and have 13.5v on the pink wire.
LTFT and STFT are flat line in live data on scan tool. LTFT and STFT are enabled in the calibration.
This is a Canadian VIN PCM for a 5.3 with 6.0 fuel tables imported. The harness was from the same vehicle. O2 sensor wires were not removed from PCM and were shortened one at a time. O2 sensors are for a Canadian 5.3.
I'm totally baffled. Any help would be greatly appreciated!!!!

That is not activity. Activity would be swings from .1v to .9v.

[blindsquirrel]

subscribed in case a tune file & log ever get posted

[rubrhammer]

Ok, so no activity, the wiring matches the schematic, 2 new sets of O2 sensors and 3 different PCMs and still no change. Closed loop is enabled. I'm at wit's end.

[blindsquirrel]

I'd love to help but you've given us nothing to look at that will help in diagnosing anything. This is as far as I can get based on what you've provided:
screenshot.19-06-2022 20.41.52.png

Have you tested the wiring? Like, by unplugging the sensors and jumpering B+ onto the signal wires, and watching the O2s in the scanner to see if voltage goes to > 900mV? If you jumper signal wires to ground, does the O2 voltage go down to < 100mV?

What O2 sensors are you using? Brand? Did they come from Ebay/Amazon? Does the wiring on the sensor-side connectors match the pinout on the harness-side connectors? Is there any change between sensors plugged in and sensors unplugged?

[rubrhammer]

BlindSquirrel, thanks for the tests to try. There really isn't anything to show you. STFT andLTFT are flat line. O2 voltage hangs at .435 to .460. ECT is above 140?,IAT is 82? Yesterday.

[blindsquirrel]

I'm done here. Good luck.

[eXo3901]

I'm still struggling with this 2002 LQ4 that won't go closed loop. I've used a different PCM, new O2 sensors and checked the wiring 3 times. The scan tool is showing activity for 4 O2 sensors when only 2 are installed. Sensor voltage ranges from .435v to .460v on all 4 lines on the scan tool. The activity is rapid changes as though it was in closed loop. It's very rapid. Scan tool then shows codes for no activity on them. Sensors are grounded to cylinder head and have 13.5v on the pink wire.
LTFT and STFT are flat line in live data on scan tool. LTFT and STFT are enabled in the calibration.
This is a Canadian VIN PCM for a 5.3 with 6.0 fuel tables imported. The harness was from the same vehicle. O2 sensor wires were not removed from PCM and were shortened one at a time. O2 sensors are for a Canadian 5.3.
I'm totally baffled. Any help would be greatly appreciated!!!!

Post a log showing this happening and the tune that was loading into the car while logging.

[rubrhammer]

That sounds good. I have no idea how to post either of them though. I'd sure appreciate some guidance.
Checked the grounds and have 0 ohms to the block. All 4 signal wires have 3 ohm between the sensor plug and the PCM.
Applying 12v to signal wires did not raise the voltage and grounding did not drop the voltage

[rubrhammer]

That sounds good. I have no idea how to post either of them though. I'd sure appreciate some guidance.
Checked the grounds and have 0 ohms to the block. All 4 signal wires have 0 ohms also.
Applying 12v to signal wires did not raise the voltage and grounding did not drop the voltage

[rubrhammer]

So the problem turned out to be ANOTHER bad set of O2 sensors. These were Bosch. First set were Denso. Both sets bought from parts stores and have brand names in the parts.