Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC B2A00-52 (Adaptive Cruise Control Unit) (2014 2015 2016 2017)
DTC B2A00-52 : ACC/CMBS Brake Initial Check Incomplete
NOTE:
- The CMBS initial check function checks the communication between the ACC unit and the VSA modulator-control unit.
- If the CMBS initial check is incomplete, the ACC and CMBS indicators come on. For the CMBS to operate properly, always do the CMBS initial check after replacing the ACC unit or the VSA modulator-control unit.
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the how to troubleshooting information .
| DTC Description | DTC | Freeze Frame |
|---|---|---|
| B2A00-52 ACC/CMBS Brake Initial Check Incomplete |
DTC (ACC)
- DTC check
-1. Turn the vehicle to the ON mode.
-2. Clear the DTC with the HDS.
-3. Turn the vehicle to the OFF (LOCK) mode, then the ON mode.
-4. Check for DTCs with the HDS.
DTC Description DTC Freeze Frame B2A00-52 ACC/CMBS Brake Initial Check Incomplete Is DTC B2A00-52 indicated?
YES
Go to step 2.
NO
Intermittent failure, the system is OK at this time.
- VSA system DTCs check
-1. Turn the vehicle to the ON mode.
-2. Check for VSA system DTCs with the HDS.
DTC Description DTC Freeze Frame Are any DTCs indicated?
YES
Go to the indicated DTC's troubleshooting .
NO
Go to step 3.
- CMBS initial check
-1. Clear the DTC with the HDS.
-2. Turn the vehicle to the OFF (LOCK) mode, then the ON mode.
-3. Select ACC from the DRIVING SUPPORT menu, then enter the FUNCTION TEST.
-4. Select ACC RELAY, and do the brake light relay test.
Brake Light Relay
Check for DTCs with the HDS.
DTC Description DTC Freeze Frame B2A00-52 ACC/CMBS Brake Initial Check Incomplete Is DTC B2A00-52 indicated?
YES
Go to step 4.
NO
Troubleshooting is complete.
- ACC unit check (update)
-1. Update the ACC unit if it does not have the latest software .
-2. Turn the vehicle to the OFF (LOCK) mode, then the ON mode.
-3. Check for DTCs with the HDS.
DTC Description DTC Freeze Frame Is DTC B2A00-52 indicated?
YES
Check for loose terminals in the ACC unit 20P connector. If the ACC unit was updated and the symptom/indication is still present, replace the ACC unit .
NO
Troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTC's troubleshooting.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.