u/HotButterfly2031

Im expierencing some wierd abs issues, Its throwing a U0121 code (loss of communication with the ABS module), but I’m honestly pretty confused by it.

Before I had the code scanned, I replaced all 4 wheel speed sensors since they weren’t too expensive and were easy enough to do. Since then I’ve checked wiring, connectors, BCM connections, ABS module connections, fuses basically all the electrical stuff I could think of.

What’s weird is the car does seem to communicate with the ABS module sometimes. At low speeds, every single time I come to a stop, the ABS kicks on and pulses the brake pedal like clockwork. The speedometer also doesn’t work most of the time, but occasionally when the ABS activates, the ABS light will suddenly clear and everything starts working normally again… until I come to a stop and it all comes back.

That’s the part confusing me: if it truly wasn’t communicating with the ABS module at all, how is the ABS still activating and sometimes temporarily restoring the speedometer and warning lights?

Has anyone dealt with something similar before? Any advice is appreciated because this one genuinely has me scratching my head lol.

Its throwing a U0121 code (loss of communication with the ABS module), but I’m honestly pretty confused by it.

Before I had the code scanned, I replaced all 4 wheel speed sensors since they weren’t too expensive and were easy enough to do before replacing them abs didnt work at all. Since then I’ve checked wiring, connectors, BCM connections, ABS module connections, fuses basically all the electrical stuff I could think of.

What’s weird is the car does seem to communicate with the ABS module sometimes. At low speeds, every single time I come to a stop, the ABS kicks on and pulses the brake pedal like clockwork. The speedometer also doesn’t work most of the time, but occasionally when the ABS activates, the ABS light will suddenly clear and everything starts working normally again… until I come to a stop and it all comes back.

That’s the part confusing me: if it truly wasn’t communicating with the ABS module at all, how is the ABS still activating and sometimes temporarily restoring the speedometer and warning lights?

Has anyone dealt with something similar before? Any advice is appreciated because this one genuinely has me scratching my head lol.