Long time forum searching and on my third fj80/lx450, everyone has been it's own puzzle. The 1997 LX450 I purchased recently has been an interesting one to say the least.
I went and replaced both knock sensors and the front knock sensors wiring harness after finding they had done the typical shear off at the plug game. Truck was kicking p0325 and p0330, as well as showing the upstream o2 sensor as showing p0135. Codes for the knock sensors seemed to abate, so I went ahead and replaced the upstream o2 sensor but after checking the resistance on the sensor i had been shipped a faulty sensor (or had wiring issues) as I went and replaced several poorly placed butt splices. After rewiring I did a resistance test from the sensor harness to the computer harness as well as checked both o2 sensors again. Here's what I got:
upstream resistance 13 ohms (+B,HT)
downstream resistant 13 ohms (+B,HT)
heated bank 1 sensor 1 (right sensor, upstream)
connector all checked out under .1 ohm
brown pin 4 to e4 24 is 0.8 ohms (4)
blue pin 3 to e5 5 is 0.9 ohms (3)
gray pin 1 to e6 1 is 0.7 ohms (1)
red-yellow pin 2 to main relay (not entirely sure how to check this)
bank 1 sensor 2 (left sensor, downstream)
orange pin 1 to e6(7) has 0.9 ohms
white pin 3 to e5 13 has 0.9 ohms
brown pin 4 to e4 24 has 1.0 ohms
red-yellow pin 2 to main relay (^^same as above)
What I got from this is now in the live data on my obd2 reader, I see outputs from both o2 sensors where I did not before. So that was good. However, I'm now kicking the upstream code and both knock sensor codes.
Here's the thought/question:
Logical next step from what I could decipher is to replace the ect and thermostat as that may be causing an issue (at least from some other posts I read). Does that seem reasonable?
I haven't seen any temp above 174 on the live data stream. I don't know if this is normal.
Check the resistance from the knock sensor harness to the ecu? This could be another phantom wiring problem, which could totally be related to the egr back of the block heat issues I was seeing.
I also realize that it could be the ecu but thus far I've consistently been replacing failed parts but the codes persist.
Few side notes one that could be related but didn't seem as bad as described by others, is the harness by the egr seemed melted a bit but none of the exposed wires seemed damaged. I went ahead and insulated that for now.
The Bimetal Vacuum valve near the rear knock sensor had one of the nipples knocked off so a hose is loose there. Part is on the order but I'm working through the above unless they could be related. (part number 2582013020)
- according to this post, #15 Another Knock Sensor Thread - https://forum.ih8mud.com/threads/another-knock-sensor-thread.880525/ this might actually be my problem.
Heater/defroster system in the vehicle have stopped functioning though again this may be another unrelated problem (likely) or related to temperature controls. I don't know but thought it was worth putting everything out there.
I went and replaced both knock sensors and the front knock sensors wiring harness after finding they had done the typical shear off at the plug game. Truck was kicking p0325 and p0330, as well as showing the upstream o2 sensor as showing p0135. Codes for the knock sensors seemed to abate, so I went ahead and replaced the upstream o2 sensor but after checking the resistance on the sensor i had been shipped a faulty sensor (or had wiring issues) as I went and replaced several poorly placed butt splices. After rewiring I did a resistance test from the sensor harness to the computer harness as well as checked both o2 sensors again. Here's what I got:
upstream resistance 13 ohms (+B,HT)
downstream resistant 13 ohms (+B,HT)
heated bank 1 sensor 1 (right sensor, upstream)
connector all checked out under .1 ohm
brown pin 4 to e4 24 is 0.8 ohms (4)
blue pin 3 to e5 5 is 0.9 ohms (3)
gray pin 1 to e6 1 is 0.7 ohms (1)
red-yellow pin 2 to main relay (not entirely sure how to check this)
bank 1 sensor 2 (left sensor, downstream)
orange pin 1 to e6(7) has 0.9 ohms
white pin 3 to e5 13 has 0.9 ohms
brown pin 4 to e4 24 has 1.0 ohms
red-yellow pin 2 to main relay (^^same as above)
What I got from this is now in the live data on my obd2 reader, I see outputs from both o2 sensors where I did not before. So that was good. However, I'm now kicking the upstream code and both knock sensor codes.
Here's the thought/question:
Logical next step from what I could decipher is to replace the ect and thermostat as that may be causing an issue (at least from some other posts I read). Does that seem reasonable?
I haven't seen any temp above 174 on the live data stream. I don't know if this is normal.
Check the resistance from the knock sensor harness to the ecu? This could be another phantom wiring problem, which could totally be related to the egr back of the block heat issues I was seeing.
I also realize that it could be the ecu but thus far I've consistently been replacing failed parts but the codes persist.
Few side notes one that could be related but didn't seem as bad as described by others, is the harness by the egr seemed melted a bit but none of the exposed wires seemed damaged. I went ahead and insulated that for now.
The Bimetal Vacuum valve near the rear knock sensor had one of the nipples knocked off so a hose is loose there. Part is on the order but I'm working through the above unless they could be related. (part number 2582013020)
- according to this post, #15 Another Knock Sensor Thread - https://forum.ih8mud.com/threads/another-knock-sensor-thread.880525/ this might actually be my problem.
Heater/defroster system in the vehicle have stopped functioning though again this may be another unrelated problem (likely) or related to temperature controls. I don't know but thought it was worth putting everything out there.
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