Initial Inspection and Diagnostic Overview
How to Troubleshoot the Electric Vacuum Pump System
System Indicator
This system has an electric vacuum pump system indicator (A).
- When the system detects a problem, the electric vacuum pump system indicator stays on.
- When the system is normal, the electric vacuum pump system indicator comes on after turning the ignition switch ON (II), then it goes off under these conditions.
- Before starting the engine.
- After starting the engine.
- Pressing the brake pedal for the first time after starting the engine.
Diagnostic Trouble Code (DTC)
- The memory can hold any number of DTCs. However, when the same DTC is detected more than once, the more recent DTC is written over the earlier one. Therefore, when the same problem is detected repeatedly, it is memorized as a single DTC.
- The DTCs are indicated in the order they occur.
- The DTCs are memorized in the PCM.
- The electric vacuum pump system DTCs are shown independently, and are treated as additional internal data by the PCM. Therefore, the electrical vacuum pump system DTCs are canceled by disconnecting the battery.
Self-diagnosis
- Self-diagnosis can be classified into two categories:
- Initial diagnosis: Done when the ignition switch is turned to ON (II), and until the electric vacuum pump system indicator goes off.
- Regular diagnosis: Done right after the initial diagnosis, until the ignition switch is turned to LOCK (0).
- When the system detects a problem, the system shifts to a fail-safe mode.
Pump Motor
The electric vacuum pump operates as needed. You can hear the motor function at times, this is normal.
The pump motor operates under these conditions:
- The system detects if the brake booster vacuum becomes low while the engine is running.
- After cold starting the engine, or when the outside temperature is very cool.
- At high altitude.
The pump motor turns off when the system detects the brake booster vacuum is sufficient. If the system detects a fault, it shifts to fail-safe mode, and turns on the electric vacuum pump system indicator.
Relationship of the Fuel and Emissions Systems
The electric vacuum pump system is a part of the brake systems. Operation relies on information from sensors in the fuel and emission systems. Review the general troubleshooting in the fuel and emissions systems section. Initial Inspection and Diagnostic Overview
How to Troubleshoot DTCs
The troubleshooting procedures assume that the cause of the problem is still present and the electric vacuum pump system indicator is still on. Following the procedure when the electric vacuum pump system indicator does not come on can result in incorrect diagnosis.
When a client has driven the vehicle abnormally, these DTCs might be stored:
- DTC P15BC: Drive the vehicle and apply/release the brake pedal repeatedly for 1 minute or more.
- DTC P0571:
- Both the brake pedal and the accelerator pedal are pressed at the same time for 5 minutes, and vehicle speed is 12 mph (20 km/h) or more.
- Stop the vehicle speed from 24 mph (40 km/h) without pressing brake pedal (using only parking brake etc.) continuously 3 times or more.
1. Ask the client about the conditions when the problem occurred and the electric vacuum pump system indicator came on, such as during braking, acceleration when vehicle was traveling at a certain speed, etc.
2. When the electric vacuum pump system indicator does not come on during the test-drive, but troubleshooting is done based on the DTC, check for loose connectors, poor contact of the terminals, etc.
3. After troubleshooting or repairs are done, clear the DTCs, and test-drive the vehicle under the same conditions as when the DTC was originally set. Make sure the electric vacuum pump system indicator does not come on.
4. Check for DTCs in other systems that are connected via the F-CAN. If there are DTCs that are related to the F-CAN, the most likely cause was that the ignition switch was turned ON (II) while the PCM connectors were disconnected.
Intermittent Failures
The term "intermittent failure" means a system may have had a failure, but it checks OK now. If the electric vacuum pump system indicator on the instrument panel does not come on, check for poor connections or loose terminals at all connectors related to the circuit that you are troubleshooting. If the indicators were on but then went out, the original problem may have been intermittent.
How to Use the HDS (Honda Diagnostic System)
1. If the electric vacuum pump system indicator stays on, connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the PCM. If it doesn't, troubleshoot the DLC circuit. Testing and Inspection
4. Check the diagnostic trouble code (DTC) and note it. Also check the on-board snapshot data, and download any data found. Then refer to the indicated DTC's troubleshooting, and begin the appropriate troubleshooting procedure.
NOTE:
- The HDS can read the DTC, freeze data, snapshot, current data, and other system data.
- For specific operations, refer to the Help menu that came with the HDS.
How to Retrieve DTCs
1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) under the driver's side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the PCM. If it doesn't, troubleshoot the DLC circuit. Testing and Inspection
4. Follow the prompts on the HDS to display the DTC(s) on the screen. After determining the DTC, refer to the DTC troubleshooting.
5. Turn the ignition switch to LOCK (0).
How to Clear DTCs
NOTE: Check for fuel and emissions systems DTCs and write down the codes indicated.
1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) under the driver's side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the PCM. If it doesn't, troubleshoot the DLC circuit. Testing and Inspection
4. Clear the DTC(s) by following the screen prompts on the HDS.
5. Turn the ignition switch to LOCK (0).