Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Good morning everyone!
Im trying to diagnose correctly this 07 lexus GS 350 AWD that has the check engine light as well as the vsc light illuminated. No drivability issues but the owner wants to know what is the cause of these lights being illuminated. I scanned the vehicle & these codes were retrieved from the engine:
*P0430-cat threshold below bank 2
*P0504-brake switch correlation A & B
Codes unders VSC:
*C1201-engine/malfunction
*C1241-low/high power supply
*U0073-comm buss off
*U0126-lost comm with steering module
Im not to familiar with these communication codes. Don't know which is priority or which effects the others. So far I checked battery voltage cranking & running. Checked both ETCS & ECU-IG fuses. Checked charging system (no AC voltage over 0.25) check battery to frame ground (under 0.10 volts) alternator output is only 13.3 volts with engine running. When I accelerate to 1500 rpm & 2500 rpm, the voltage does not increase. (This is with all electrical components on in the vehicle) When I release pedal to allow the vehicle to idle, the voltage drops to 12.6-12.8 volts then rises back to 13.3 volts. Im not sure if this is the issue or not. Thank you all for any feedback!
Do the comm codes come right back after clearing the codes?
I would expect the P0430 stored in the engine module to in turn kick on the VSC light.
I would try to determine if it needs a cat, clear the codes and see if the VSC light light/codes stay away until the ECM kicks up the P0430 again.
Like Noah said, I'd immediately suspect the P0430 as the code that's setting the dash lights. If you haven't cleared the codes yet, you can go into Global OBD and see what's stored there.
C1201 is a roadsign code for the P0430. C1241 is set in almost every Toyota ABS/VSC I come across. :silly: Unless there's a current communication issue, I'd ignore the U-codes.
Thank you so much Noah sir for your response! I found a bit more information from the owner of the vehicle that the catalytic converter was replaced on that bank & few months ago & the shop that installed it said the rear main seal was leaking. So He called them & they told Him to bring the vehicle back so they could repair the seal & it would fix the P0430 code.
Morning Tyler sir! Thank you very much for your response and input sir! I didn't know that the P0430 code would trigger the other codes on Toyota vehicles. This vehicle is has a rear main seal leak that is effecting the catalytic converter according to the shop that replaced it a few months ago. Once they repair it, I will bring it back to my shop & see how it operates. I will post an update! Thank you again sir!
Morning Tyler sir! Thank you very much for your response and input sir! I didn't know that the P0430 code would trigger the other codes on Toyota vehicles. This vehicle is has a rear main seal leak that is effecting the catalytic converter according to the shop that replaced it a few months ago. Once they repair it, I will bring it back to my shop & see how it operates. I will post an update! Thank you again sir!
The rear main was impacting the catalytic converter operation? :huh: Well, I can say that I've never seen that before...
