trojan84

I’ve recently motor swapped my 1994 Toyota pickup. Truck runs great, but check engine light is on. I’ve ran diagnostics using the jumper cable, and it’s giving me a code 27. Now since I’m in California, I have two o2 sensors. This one is giving me a trouble code for the downstream o2 sensor. I’d like to add that my headers and exhaust system with new catalytic converter were replaced with LC Engineering parts. New denso o2 sensors.

I’ve tried disconnecting battery and efi relay to clear code, but cel stays on even after doing this. I’ve put the old o2 sensor back on, and even put in a universal denso sensor with no luck. Would a o2 sensor fouler work? Other threads mention changing a coolant temp sensor or knock sensor? What’s the next step before I take it to the shop and spend on 3-4 hours min of labor. I’ve ordered another plug and play denso sensor and currently waiting for it to see if that may solve the problem.

osv

it's a 4-wire sensor, right? i'd check the wiring harness.

trojan84

correct, denso 4 wire sensor. Two black, blue and white. What’s the best way to go about that? Where are the typical areas to check. I am waiting on my Haynes book for the pickup. I’m also not certain on how to check voltage with multimeter.

osv

so it was originally a 22re, you just swapped in another 22re?

since it's new it's probably a good sensor, so maybe do a visual on the harness, look for breaks in the wire and burned/melted wiring, and also ohm it out all the way back to ecu if possible.

you are gonna need a wiring diagram to figure out which connection it is on the ecu, i don't know if it's in the toyota fsm but that's the place to start, should be able to download a copy, find links here on yotatech or worst case google it.

trojan84

[QUOTE=osv;52497561]so it was originally a 22re, you just swapped in another 22re?

since it's new it's probably a good sensor, so maybe do a visual on the harness, look for breaks in the wire and burned/melted wiring, and also ohm it out all the way back to ecu if possible.

you are gonna need a wiring diagram to figure out which connection it is on the ecu, i don't know if it's in the toyota fsm but that's the place to start, should be able to download a copy, find links here on yotatech or worst case google it.

[/QUOTE


correct, swapped with the same engine. The previous owner did move the battery from the left to the right side and the air box from the right to the left. I’ve changed it back to its original location and added a LC engineering intake. So it’s all good from there. I just can’t seem to get that check engine light off whatsoever.

I’ll check the harness again, but when checking the o2 sensors. I don’t remember seeing anything that would’ve caused a bad connection. The cables to the o2 sensors do look in tact.