Hi, I purchased a 08 Lexus LS 460 rear wheel drive. I fixed some bodywork on the driver's fender, front bumper and driver's headlight from a light hit (no airbags went off). I need to get it passed CA emissions, but keep encountering a trouble code. I purchased an Amazon after market 02 air fuel meter, and it continues to generate a P2240 code. I then purchased a Denso air fuel meter, part number 234-9058; it still generates the same code. I grafted the sensor activity on a scan tool, and found that Bank 1 fluctuates its regular from roughly 5V to 1V, whereas Bank 2 Sensor 1 only barely fluctuates from 3.328V to 3.273V. I have checked the connector ends, they appear good. I have checked all insulation on the lead harness and see no piercing, burn marks, or anything irregular. Because I have no heated 02 code I assume the power and ground are good? I assume the code is for a shorted or open wire, is there anything I am missing? A ground point for only the Bank 2 side? Is there a wiring harness diagram someone would have where I could bypass harness lead to the ECU? Any help is appreciated! Thanks, Jay

 

Super appreciate any help!
thank you

 

If you want to get wiring diagram, you will need access to a repair manual or you can get subscription to alldata or a similar site.

Did the car come with the error code or it appeared some time after the purchase?

 

"P2240 Open in the circuit between terminals A2A+ and A2A- of the AF sensor while engine is running (2 trip detection logic)"



Please guys, when talking about air/fuel sensors in LS, please differentiate between A/F ones (upstream) and HO2s (downstream). I personally call A/F ones 'wideband' and post cat ones 'Lambda'. Otherwise it gets really confusing.

 

Hi, thanks for responding. It came with the code, along with a couple of other codes for cracked harness connectors for cam sensor, that seem to be resolved with new pigtail.

 

Thank you so much! That is exactly what I was looking for. I assume I would disconnect battery, unplug ECU connector, back probe A2A+*2 and A2A-*2, and measure resistance from the ECU to the Passenger Wideband A/F connector, while the harness is unplugged?Perhaps, front probe it from a cutoff Wideband sensor that I removed pre-Denso? Seeing that back probing it is going to be next to impossible, with the room in the firewall. Really not so smart for having Toyota heritage!

Is there any other reading I can do from the ECU side?

If I get a shorted reading, I would run new lines from ECU and solder to the engine harness near the A/F Wideband harness connector?

Thanks again so much, I am cleaning up and looking for my back probing pins to connect. Will keep everybody informed! Thank god I have more broken cars to fix and drive

 

Hey all, not so great news for me.

Tested continuity from the ECU to the Passenger Wideband A/F sensor, I had continuity on A2A-2, but not continuity between A2A+2.

Was super happy, thought this would resolve the issue, cut the wire 4 inches behind the lead on the black A2A+2 wire, soldered a slightly heavier gauge and then ran it directly to the oxygen sensor itself on the A2A+2 connection, cut the blue aluminized wire behind the connector, taped and insulated. The wire harness connector to the Wideband A/f is impossibly hard to get to, because it is so tight to the firewall, that's why I ran it to the sensor directly, feeling that I would bypass the 1 out of 4 A/F sensor connector connections too.

Unfortunately, that did not fix the problem--I have the same code showing up and same voltage staying at a steady 3.328V to 3.273V.

Not sure where to go from here. On the flowchart, it does list the ECU, could the ECU have shorted out and fried? Is there a way to buy an EBAY used ECU and code it to car, not going through the dealer? Or is it worth a peek inside the ECU for a burnt portion?

Is there anything else I could be missing? I did not test the heated circuit.

Any help is super appreciated.

 

Hmmm plot thickens. Did you check short to gnd/positive on any of wires? Did you isolate the branch that is broken?

 

Testing has left me more confused...I have no shorts from A2A+2 or A2A-2. The AF Wideband sensors have continuity to ground on the negative lines. The positive ones float at 3.3 when car running. Backprobed at ECM, even when I accelerate the car, AF 1 sensor does not fluctuate. I thought this would be the same reading as the voltage that the car scanner is graphing? (Bank 1 fluctuates from 1-5V on scanner, problem Bank 2 stays steady on scanner). When I backprobe ECM, both positive lines stay steady at 3.3. I probed the HA1A and HA2A, bank 1 (the non problem side), reads between 6-8V with car running, whereas bank 2 stays steady at 14V. Am I missing something? I assume the HAs are for heated oxygen sensor?

The only thing I find different from Bank 1 and 2 on the Wideband sensor is the HAs. HA1s fluctuates voltage, whereas HA2s has 14V. I have not been able to find a pin out of the +B at ECM.

Any help again is appreciated. I am not sure if the plot thickens or thins! I don't know why the meter didn't pick up the fluctuating reading of a working Wideband. My Bank 1 meter was not set on Max or any setting like that.

 

PMed FWIW...

 

Ｉhad the same issue on my GS460, wondering if you got around to fix it? A mechanic said its ECM needs repair or replaced but heck I don’t know anything about electricals

 

Hey man. Did you ever solve this?

 

I got same but have swapped out new denso sensors twice and ran new wire checked fuses