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.
VSA DTC 77-11
DTC 77-11 : Brake Booster Pressure Sensor Circuit Malfunction
| DTC Description | DTC | Freeze Frame |
|---|---|---|
| 77-11 Brake Booster Pressure Sensor Circuit Malfunction |
DTCs (VSA)
- Problem verification
-1. Turn the vehicle to the ON mode.
-2. Clear the DTC with the HDS.
-3. Turn the vehicle to the OFF (LOCK) mode.
-4. Turn the vehicle to the ON mode, then wait for a few seconds or more.
-5. Check for DTCs with the HDS.
DTC Description DTC Freeze Frame 77-11 Brake Booster Pressure Sensor Circuit Malfunction Is DTC 77-11 indicated?
YES
The failure is duplicated. Go to step 2.
NO
Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting. .
- Brake booster pressure sensor check 1
-1. Check and note the parameter(s) below with the HDS.
Signal Current conditions Values Unit BRAKE BOOSTER PRESSURE SENSOR A VOLTAGE Is the voltage between 0.165-3.201 V?
YES
Go to step 3.
NO
- Brake booster pressure sensor check 2
-1. Check and note the parameter(s) below with the HDS.
Signal Current conditions Values Unit BRAKE BOOSTER PRESSURE SENSOR A Does the value indicate -112.5 kPa (-844 mmHg, -33.22 inHg)?
YES
Go to step 8.
NO
Go to step 4.
- Shorted wire check (SVCC1, VAC1 lines to ground)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connectors.
VSA modulator-control unit 38P connector Brake booster pressure sensor 3P connector -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode VSA modulator-control unit 38P connector: disconnected Brake booster pressure sensor 3P connector: disconnected Test circuit SVCC1 Test point 1 Brake booster pressure sensor 3P connector No. 1 (LT GRN) Test point 2 Body ground Test circuit VAC1 Test point 1 Brake booster pressure sensor 3P connector No. 3 (BRN) Test point 2 Body ground Is there continuity?
YES
Repair a short to body ground in the wire between brake booster pressure sensor and the VSA modulator-control unit.
NO
The SVCC1 and VAC1 wires are not shorted to body ground. Go to step 5.
- Open wire check (SVCC1, VAC1 lines)
-1. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode VSA modulator-control unit 38P connector: disconnected Brake booster pressure sensor 3P connector: disconnected Test circuit SVCC1 Test point 1 VSA modulator-control unit 38P connector No. 30 (LT GRN) Test point 2 Brake booster pressure sensor 3P connector No. 1 (LT GRN) Test circuit VAC1 Test point 1 VSA modulator-control unit 38P connector No. 27 (BRN) Test point 2 Brake booster pressure sensor 3P connector No. 3 (BRN) Is there continuity?
YES
The SVCC1 and VAC1 wires are not open. Go to step 6.
NO
Repair an open in the wire between brake booster pressure sensor and the VSA modulator-control unit.
- Shorted wire check (SVCC1, SGND1 lines wire to wire)
-1. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode VSA modulator-control unit 38P connector: disconnected Brake booster pressure sensor 3P connector: disconnected Test circuit SVCC1, SGND1 Test point 1 Brake booster pressure sensor 3P connector No. 1 (LT GRN) Test point 2 Brake booster pressure sensor 3P connector No. 2 (GRY) Is there continuity?
YES
Repair a short in the wires between brake booster pressure sensor and the VSA modulator-control unit.
NO
The SVCC1 and SGND1 wires are not shorted in the wires. Go to step 7.
- Shorted wire check (VAC1, SGND1 lines wire to wire)
-1. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode VSA modulator-control unit 38P connector: disconnected Brake booster pressure sensor 3P connector: disconnected Test circuit VAC1, SGND1 Test point 1 Brake booster pressure sensor 3P connector No. 2 (GRY) Test point 2 Brake booster pressure sensor 3P connector No. 3 (BRN) Is there continuity?
YES
Repair a short in the wires between brake booster pressure sensor and the VSA modulator-control unit.
NO
The VAC1 and SGND1 wires are OK. Go to step 11.
- Open wire check (SGND1 line)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connectors.
VSA modulator-control unit 38P connector Brake booster pressure sensor 3P connector -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode VSA modulator-control unit 38P connector: disconnected Brake booster pressure sensor 3P connector: disconnected Test circuit SGND1 Test point 1 VSA modulator-control unit 38P connector No. 34 (GRY) Test point 2 Brake booster pressure sensor 3P connector No. 2 (GRY) Is there continuity?
YES
The SGND1 wire is OK. Go to step 9.
NO
Repair an open in the wire between brake booster pressure sensor and the VSA modulator-control unit.
- Shorted wire check (VAC1 line to power)
-1. Turn the vehicle to the ON mode.
-2. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode VSA modulator-control unit 38P connector: disconnected Brake booster pressure sensor 3P connector: disconnected Test circuit VAC1 Test point 1 Brake booster pressure sensor 3P connector No. 3 (BRN) Test point 2 Body ground Is there 0.1 V or more?
YES
Repair a short to power in the wire between brake booster pressure sensor and the VSA modulator-control unit.
NO
The VAC1 wire is not shorted to power. Go to step 10.
- Shorted wire check (SVCC1, VAC1 lines wire to wire)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode VSA modulator-control unit 38P connector: disconnected Brake booster pressure sensor 3P connector: disconnected Test circuit SVCC1, VAC1 Test point 1 Brake booster pressure sensor 3P connector No. 1 (LT GRN) Test point 2 Brake booster pressure sensor 3P connector No. 3 (BRN) Is there continuity?
YES
Repair a short in the wires between brake booster pressure sensor and the VSA modulator-control unit.
NO
The SVCC1 and VAC1 wires are OK. Go to step 11.
- Brake booster pressure sensor check 3 (substitution)
-1. Substitute a known-good brake booster pressure sensor .
-2. Reconnect the following connectors.
VSA modulator-control unit 38P connector Brake booster pressure sensor 3P connector -3. Turn the vehicle to the ON mode.
-4. Clear the DTC with the HDS.
-5. Turn the vehicle to the OFF (LOCK) mode.
-6. Turn the vehicle to the ON mode, then wait for a few seconds or more.
-7. Check for DTCs with the HDS.
DTC Description DTC Freeze Frame 77-11 Brake Booster Pressure Sensor Circuit Malfunction Is DTC 77-11 indicated?
YES
Go to step 12.
NO
- VSA modulator-control unit check (update)
-1. Update the VSA modulator-control unit if it does not have the latest software .
-2. Turn the vehicle to the OFF (LOCK) mode.
-3. Turn the vehicle to the ON mode, then wait for a few seconds or more.
-4. Check for DTCs with the HDS.
DTC Description DTC Freeze Frame Is DTC 77-11 indicated?
YES
Check for loose terminals in the VSA modulator-control unit 38P connector. If the VSA modulator-control unit was updated and the symptom/indication is still present, replace the VSA modulator-control unit .
NO
Troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTCs 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.