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 77-13
DTC 77-13 : Brake Booster Pressure Sensor Incorrect Correlation
Special Tools Required
Vacuum/Pressure Gauge, 0-4 inHg 07JAZ-001000B
| DTC Description | DTC | Freeze Frame |
|---|---|---|
| 77-13 Brake Booster Pressure Sensor Incorrect Correlation |
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. Start the engine.
-5. Press the accelerator pedal several times, and press the brake pedal hard several times, then repeat five times.
-6. Check for DTCs with the HDS.
DTC Description DTC Freeze Frame 77-13 Brake Booster Pressure Sensor Incorrect Correlation Is DTC 77-13 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. .
- Vacuum hose check
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Check for leakage, a blockage, and damage in the vacuum hose connected to the brake booster pressure sensor.
Is the vacuum hose OK?
YES
Go to step 3.
NO
Repair or replace the vacuum hose.
- Brake booster pressure sensor check 1
-1. Press the brake pedal several times to deplete the vacuum.
-2. Turn the vehicle to the ON mode.
-3. Check and note the parameter(s) below with the HDS.
Signal Current conditions Values Unit BRAKE BOOSTER PRESSURE SENSOR A Does the value indicate between -5 kPa (-37.5 mmHg, -1.5 inHg) and 5 kPa (37.5 mmHg, 1.5 inHg)?
YES
Go to step 4.
NO
- Brake booster pressure sensor check 2
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Install the vacuum/pressure gauge (A) and a suitable hose (B) between the brake booster and the vacuum hose (C).
-3. Start the engine.
-4. Check and note the parameter(s) below with the HDS.
Signal Current conditions Values Unit BRAKE BOOSTER PRESSURE SENSOR A Is the difference between BRAKE BOOSTER PRESSURE SENSOR A and the value of vacuum/pressure gauge +/-5 kPa (+/-37.5 mmHg, +/-1.5 inHg) or more?
YES
Replace brake booster pressure sensor .
NO
Go to step 5.
- 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. Start the engine.
-4. Press the accelerator pedal several times, and press the brake pedal hard several times, then repeat five times.
-5. Check for DTCs with the HDS.
DTC Description DTC Freeze Frame Is DTC 77-13 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.