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.
2021 Subaru Ascent BaseFACTORY OEM SERVICE PROCEDURE
Reverse Automatic Braking System DTCS
REVERSE AUTOMATIC BRAKING SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| Code | Reference |
|---|---|
| B2C00 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C00 SONAR CONTROL MODULE CIRCUIT . |
| B2C01 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C01 RR SONAR CONTROL MODULE CIRCUIT . |
| B2C02 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C02 RRC SONAR CONTROL MODULE CIRCUIT . |
| B2C03 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C03 RL SONAR CONTROL MODULE CIRCUIT . |
| B2C04 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C04 RLC SONAR CONTROL MODULE CIRCUIT . |
| B2C05 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C05 SONAR CONTROL MODULE POWER SUPPLY . |
| B2C06 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C06 RR SONAR SENSOR CIRCUIT/NO SIGNAL . |
| B2C07 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C07 RR SONAR SENSOR/SONAR CONTROL MODULE CIRCUIT . |
| B2C08 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C08 RRC SONAR SENSOR CIRCUIT/NO SIGNAL . |
| B2C09 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C09 RRC SONAR SENSOR/SONAR CONTROL MODULE CIRCUIT . |
| B2C0A | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C0A RL SONAR SENSOR CIRCUIT/NO SIGNAL . |
| B2C0B | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C0B RL SONAR SENSOR/SONAR CONTROL MODULE CIRCUIT . |
| B2C0C | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C0C RLC SONAR SENSOR CIRCUIT/NO SIGNAL . |
| B2C0D | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C0D RLC SONAR SENSOR/SONAR CONTROL MODULE CIRCUIT . |
| B2C0E | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C0E RR SONAR HARNESS HIGH . |
| B2C0F | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C0F RR SONAR HARNESS LOW . |
| B2C10 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C10 RRC SONAR HARNESS HIGH . |
| B2C11 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C11 RRC SONAR HARNESS LOW . |
| B2C12 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C12 RL SONAR HARNESS HIGH . |
| B2C13 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C13 RL SONAR HARNESS LOW . |
| B2C14 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C14 RLC SONAR HARNESS HIGH . |
| B2C15 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C15 RLC SONAR HARNESS LOW . |
| B2C16 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C16 RRC SONAR HARNESS HIGH/RRC SONAR CONTROL MODULE CIRCUIT . |
| B2C17 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C17 RLC SONAR HARNESS HIGH/RLC SONAR CONTROL MODULE CIRCUIT . |
| B2C18 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C18 RR SONAR HARNESS HIGH/RR SONAR CONTROL MODULE CIRCUIT . |
| B2C19 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C19 RL SONAR HARNESS HIGH/RL SONAR CONTROL MODULE CIRCUIT . |
| B2C1A | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C1A RRC SONAR SENSOR . |
| B2C1B | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C1B RLC SONAR SENSOR . |
| B2C1C | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C1C RR SONAR SENSOR . |
| B2C1D | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C1D RL SONAR SENSOR . |
| B2C1E | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C1E RRC SONAR HARNESS LOW/RRC SONAR CONTROL MODULE CIRCUIT . |
| B2C1F | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C1F RLC SONAR HARNESS LOW/RLC SONAR CONTROL MODULE CIRCUIT . |
| B2C20 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C20 RR SONAR HARNESS LOW/RR SONAR CONTROL MODULE CIRCUIT . |
| B2C21 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C21 RL SONAR HARNESS LOW/RL SONAR CONTROL MODULE CIRCUIT . |
| B2C22 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B2C22 EYESIGHT SYSTEM . |
| U0077 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0077 LOCAL CAN COMMUNICATION BUS OFF . |
| U0100 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0100 LOST COMMUNICATION WITH ECM/PCM "A" . |
| U0101 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0101 LOST COMMUNICATION WITH TCM . |
| U0122 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE . |
| U0140 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0140 LOST COMMUNICATION WITH BODY CONTROL MODULE . |
| U0155 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0155 LOST COMMUNICATION WITH INSTRUMENT PANEL CLUSTER (IPC) CONTROL MODULE . |
| U0401 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0401 INVALID DATA RECEIVED FROM ECM/PCM "A" . |
| U0402 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0402 INVALID DATA RECEIVED FROM TCM . |
| U0416 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0416 INVALID DATA RECEIVED FROM VEHICLE DYNAMICS CONTROL MODULE . |
| U0422 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0422 INVALID DATA RECEIVED FROM BODY CONTROL MODULE . |
| U0423 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0423 INVALID DATA RECEIVED FROM INSTRUMENT PANEL CLUSTER CONTROL MODULE . |
| U0457 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U0457 INVALID DATA RECEIVED FROM INFORMATION CENTER "A" . |
| U1235 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U1235 LOST COMMUNICATION WITH EYESIGHT . |
| U1433 | Ref. to REVERSE ASSIST BRAKING (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC U1433 INVALID DATA RECEIVED FROM EYESIGHT . |
Factory Service Tools
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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.