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I believe its made in Canada , vin starts with 2. So, on my 300 mile trip yesterday. There is no warning popping up on the dash anymore, felt good upon arrival. On the way home the auto bright function was on and worked perfect for about an hour, then the high beams quit working. Stopped for gas and powered down , high beams worked again for maybe an hour and quit again just before getting home. The high beam indicator on the dash always comes on, it cuts the fog lights out, no high beam lights. Doesn't matter if you have auto enabled or using the switch manually. Once they quit, they quit.
Tomorrow I'm going to call Lexus of Canada and try and corner them concerning the warranty as my local dealers say they can't honor it. From there I'm not sure. After inspecting the plugs and wiring I wonder about the headlight ecu, the chassis harness plugs into the ecu, Does the ecu plug into the bottom of the headlight? That's a possible connection that I didn't look at. Also going to try and scan it again and see if I still have that fault or if there is no fault now and the lights don't work. Odd that I don't have the warning anymore.
Does the ecu plug into the bottom of the headlight? No.
That's a possible connection that I didn't look at. Also going to try and scan it again and see if I still have that fault or if there is no fault now and the lights don't work. Odd that I don't have the warning anymore.
Scan it again.
No, the ECU doesn't plug into the bottom of the headlights, it's only housed there.
*14: Before Aug. 2019 production
*15: From Aug. 2019 production
A49 is the headlight ECU sub-assembly LH connector.
A94 is the fog light assembly LH connector
A20 and A21 are the connectors for the headlight assembly LH.
A19 is cornering the light assembly LH connector
AA is one of the three chassis ground point that you cleaned.
Check both connectors A20 and A94.
Pins 23 and 24 of connector 49 should be 60Ω with DVOM.
If you measure the voltage at CANH, it's between 2.8 - 3.2 volts and CANL is between 2.0 - 2.4 volts.
Awesome info again! Drove it this morning, malfunction warning is popping up today. Probly be Saturday before I can look at it again, long work week to get thru. I'll report back then. Thank you!
Awesome info again! Drove it this morning, malfunction warning is popping up today. Probly be Saturday before I can look at it again, long work week to get thru. I'll report back then. Thank you!
I stand corrected, the headlight ECU sub-assembly is connected to the headlight assembly. Attached is another headlight ECU sub-assembly diagrams with the AFS.
To get a proper resistance reading of terminals 23 and 24 of the CAN bus, all modules should be asleep.
Sorry, I keep meaning to update this. So 3 weeks ago I brought it back in the shop. pulled the inner fender well and the battery. I pulled the 3 ground lugs off again from under the drivers headlight and hit them with some 80g, attaching bolts as well. I then unplugged the left headlight ecu and dropped it down from the headlight. There are 2 harnesses that plug into it. Unplugged and inspected them both, look fine.. They do not have a lot of positive reassurance when plugging them back in however, there not loose. Put everything back together. Have not had a single issue in 3 weeks. It's looking like a poor connection, I can't say which one of the things I did fixed it though. In my experience this will probly return at some point, for the moment we'll see how it goes. Thanks a lot for the help!!
No, the ECU doesn't plug into the bottom of the headlights, it's only housed there.
*14: Before Aug. 2019 production
*15: From Aug. 2019 production
A49 is the headlight ECU sub-assembly LH connector.
A94 is the fog light assembly LH connector
A20 and A21 are the connectors for the headlight assembly LH.
A19 is cornering the light assembly LH connector
AA is one of the three chassis ground point that you cleaned.
Check both connectors A20 and A94.
Pins 23 and 24 of connector 49 should be 60Ω with DVOM.
If you measure the voltage at CANH, it's between 2.8 - 3.2 volts and CANL is between 2.0 - 2.4 volts.
May I ask where did you obtain this electrical diagram?
Sorry, I keep meaning to update this. So 3 weeks ago I brought it back in the shop. pulled the inner fender well and the battery. I pulled the 3 ground lugs off again from under the drivers headlight and hit them with some 80g, attaching bolts as well. I then unplugged the left headlight ecu and dropped it down from the headlight. There are 2 harnesses that plug into it. Unplugged and inspected them both, look fine.. They do not have a lot of positive reassurance when plugging them back in however, there not loose. Put everything back together. Have not had a single issue in 3 weeks. It's looking like a poor connection, I can't say which one of the things I did fixed it though. In my experience this will probly return at some point, for the moment we'll see how it goes. Thanks a lot for the help!!
Had same issue two years ago till I convinced my dealership to replace the RH headlight which fixed the problem till today it came back again which I think it’s either a manufacturing issue or cooling issue.
this malfunction when comes up when the temperature is hot enough. I did some research for similar issue and found some people fix it by replacing the high beam lens with similar aftermarket ones which am not going to do risking Lexus to catch fire.
