DTC P0557 (2019 2020 2021)

DTC P0557  : Brake Booster Pressure Sensor A Circuit Low Voltage

NOTE:  Before you troubleshoot, review the general troubleshooting information. - Refer to: How to Troubleshoot the Brake Booster Pressure Monitoring System .

DTC (EVPS)

1. Problem verification

   - 1. Turn the vehicle to the ON mode.

   - 2. Check the parameter(s) below with the HDS.

   Signal	Threshold		Current Condition
   	Values	Unit	Values	Unit
   BRAKE BOOSTER PRESSURE SENSOR (A) VOLTAGE	Less than 0.43	V

   Do the current condition(s) match the threshold?

   YES 

   Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the brake booster pressure sensor and the PCM.

2. Determine possible failure area (MPMON line, others)

   - 1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Disconnect the following connector.

   Brake booster pressure sensor 3P connector

   - 3. Turn the vehicle to the ON mode.

   - 4. Check the parameter(s) below with the HDS.

   Signal	Threshold		Current Condition
   	Values	Unit	Values	Unit
   BRAKE BOOSTER PRESSURE SENSOR (A) VOLTAGE	About 5.0	V

   Do the current condition(s) match the threshold?

   YES 

   Go to step 3.

   NO 

   Go to step 5.

3. Brake booster pressure sensor check

   - 1. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode
   	Brake booster pressure sensor 3P connector: disconnected
   Test point 1	Brake booster pressure sensor 3P connector (female terminals) No. 1:
   Test point 2	Brake booster pressure sensor 3P connector (female terminals) No. 3:

   Courtesy of HONDA, U.S.A., INC.

   Is there about 5 V?

   YES 

   Replace the brake booster pressure sensor .

   NO 

   Go to step 4.

4. Open wire check (VCC6 line, VCC2 line)

   - 1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Jump the SCS line with the HDS.

   NOTE:  Before disconnecting the PCM connector, jump the SCS line with the HDS, and wait for more than 1 minute.

   - 3. Disconnect the following connector.

   PCM connector E (80P)

   - 4. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Brake booster pressure sensor 3P connector: disconnected
   	PCM connector E (80P): disconnected
   Test point 1	Brake booster pressure sensor 3P connector (female terminals) No. 3:
   Test point 2	PCM connector E (80P) No. 76 - Refer to: PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021), or PCM Connector for Inputs and Outputs(6-Speed A/T) (2016 2017 2018 2019 2020)

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM - Refer to: PCM Removal and Installation (9-Speed A/T) (2019 2020 2021), or PCM Removal and Installation (6-Speed A/T), ('16-'18 9-Speed A/T) , then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM - Refer to: PCM Removal and Installation (9-Speed A/T) (2019 2020 2021), or PCM Removal and Installation (6-Speed A/T), ('16-'18 9-Speed A/T) .

   NO 

   Repair an open in the VCC6 wire and the VCC2 wire between PCM connector E (80P) terminal No. 76 and the brake booster pressure sensor.

5. Shorted wire check (MPMON line)

   - 1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Jump the SCS line with the HDS.

   NOTE:  Before disconnecting the PCM connector, jump the SCS line with the HDS, and wait for more than 1 minute.

   - 3. Disconnect the following connector.

   PCM connector A (51P)

   - 4. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Brake booster pressure sensor 3P connector: disconnected
   	PCM connector A (51P): disconnected
   Test point 1	Brake booster pressure sensor 3P connector (female terminals) No. 2:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Repair a short in the MPMON wire between PCM connector A (51P) terminal No. 21 and the brake booster pressure sensor.

   NO 

   Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM - Refer to: PCM Removal and Installation (6-Speed A/T), ('16-'18 9-Speed A/T), or PCM Removal and Installation (9-Speed A/T) (2019 2020 2021) , then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM - Refer to: PCM Removal and Installation (6-Speed A/T), ('16-'18 9-Speed A/T), or PCM Removal and Installation (9-Speed A/T) (2019 2020 2021) .