Hello. I'm writing about a specific issue I've encountered with my 2011 Lexus CT20
Related fault codes
C2123
Comments (1)
Anonymous
2019-07-09 15:19
C2123 in Lexus vehicles refers to 'No Signal from Transmitter ID 3 in Main Mode 0'. This code is typically linked to the Tire Pressure Monitoring System (TPMS), with possible causes including a faulty TPMS valve, transmitter, antenna, or wiring issues. However, in my case, the symptoms were not just TPMS warnings — while driving on the highway, all four brake warning lights illuminated, and the brake pedal felt firmer than normal, suggesting loss of power assist. The dealer initially diagnosed an ABS booster leak, which resolved after replacement — but the brake pedal returned to normal and warnings disappeared.
I later tested at another shop where no braking faults were found, though they reported code C2123. Most online resources list this code as a TPMS issue (e.g., low pressure light not resetting), but I noticed that searching for 'C2123' redirects to pages about U0129 — which is related to power loss to the brake module and could explain my symptoms.
This raises a key question: Could C2123 in a 2011 CT200h actually be linked to braking system faults, such as ABS or brake assist failure? The symptoms (brake warning lights on, firm pedal) strongly suggest an underlying issue with the brake module or power assist — not just tire pressure.
I'm seeking input from other owners of 2011 CT200h models who have encountered C2123 and experienced similar braking-related warnings. Does this code in your vehicle indicate a TPMS fault, or could it be masking a deeper brake system problem?
Thanks,
AJ
C2123 in Lexus vehicles refers to 'No Signal from Transmitter ID 3 in Main Mode 0'. This code is typically linked to the Tire Pressure Monitoring System (TPMS), with possible causes including a faulty TPMS valve, transmitter, antenna, or wiring issues. However, in my case, the symptoms were not just TPMS warnings — while driving on the highway, all four brake warning lights illuminated, and the brake pedal felt firmer than normal, suggesting loss of power assist. The dealer initially diagnosed an ABS booster leak, which resolved after replacement — but the brake pedal returned to normal and warnings disappeared. I later tested at another shop where no braking faults were found, though they reported code C2123. Most online resources list this code as a TPMS issue (e.g., low pressure light not resetting), but I noticed that searching for 'C2123' redirects to pages about U0129 — which is related to power loss to the brake module and could explain my symptoms. This raises a key question: Could C2123 in a 2011 CT200h actually be linked to braking system faults, such as ABS or brake assist failure? The symptoms (brake warning lights on, firm pedal) strongly suggest an underlying issue with the brake module or power assist — not just tire pressure. I'm seeking input from other owners of 2011 CT200h models who have encountered C2123 and experienced similar braking-related warnings. Does this code in your vehicle indicate a TPMS fault, or could it be masking a deeper brake system problem? Thanks, AJ