Fault code C1A6A
#1
Driver School Candidate
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Fault code C1A6A
Hi All, New to the site but not to Lexus having owned LS460, LS600hl gen 3 and currently LS600hl gen 4, fantastic cars. However I have a problem, following a minor accident which involved a scratch to the right front wing, bumper and head light. It was only cosmetic. But to bring the car back to its immaculate condition some paintwork and a replacement headlight was required. Since completion of the work I now get a PCS system warning on the dash (when it is dark and the headlamps are on) and a code diagnostic report of C1A6A Infrared signal circuit. Having checked for bad connections to the headlight unit etc. everything looks good. By putting the old headlamp back in the car no faults are recorded. This would indicate the fault is in the new headlamp. My question is does the new headlamp assembly need coding to the car in some way? Or is it faulty? It appears to work ok in all other respects but I cant check if the infrared sensor is actually coming on when it should. Any ideas?? Regards Tony
#2
Wrong headlight.. Get a correct one (it will cost you).
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BlazeViper (09-04-22)
#3
Pole Position
#4
Nope. He installed 'plain' HL, instead of Infrared equipped one.
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Anfanger (09-03-22)
#5
Driver School Candidate
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Hi Boykie, Thanks for your response, yes this did cross my mind, but having cross referenced the part number with the Lexus dealer who supplied the part and also double checked the part number with another Lexus dealer not involved who also gave the same part number I wondered if this was possible. Both headlights appear to be identical, the part number on the box is correct with what they ordered. But yes it is a possibility. This is one avenue I will be going down returning the headlamp but just wanted to check first if it required coding to the car. Thanks again.
#6
Pole Position
If you post pictures of both, it might accelerate resolution of your issue.
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Boykie (09-03-22)
#7
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#8
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#9
Driver School Candidate
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Hi What I need to know is does replacing the headlight need it coding to the car or are they plug and play? If theyare supposed to be plug and play then its back to the supplier>
Last edited by Tonyls600h; 09-03-22 at 06:53 AM.
#10
NO. You installed WRONG headlight. You can not identify if it's IR-enabled just by looking. You need IR-enabled headlight. That's it.
#11
Driver School Candidate
Thread Starter
Thanks Boykie, looks like its back to the supplier then as they ordered it on the records they had on my car i.e. chassis number etc. etc. Trouble is it took 8 weeks to get the part from Lexus in the first place.
#12
If you look at bottoms of headlights (unmounted) - IR ones have a triangular cover, non-IR ones have no cover.
EU/UK spec IR-enabled headlights can be an unobtanium. I had to order US ones myself because of no availability.
EU/UK spec IR-enabled headlights can be an unobtanium. I had to order US ones myself because of no availability.
#13
There is another possibility. Your new headlight is correct, but whoever installed it failed to transfer some parts from old one (retractor control ecu) - theory. PMed you for further diag.
#14
Driver School Candidate
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#15
I failed to catch it's about 600. Reply to PM anyways to investigate. Take a better pic of the connectors (I need to see populated pins) as well if possible.
Last edited by Boykie; 09-03-22 at 05:38 PM.