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Home >> Mazda >> 2022 >> MX-5 Miata RF Club >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> On-Board Diagnostics - Electric Vacuum Pump (EVP) >> DTC C101B-16/C101B-17: Vacuum Sensor 1 Circuit [EVP Control Unit] >> Diagnostic Procedure

Diagnostic Procedure

DTC C101B:16/C101B:17 (EVP CONTROL UNIT) DIAGNOSTIC PROCEDURE

Step INSPECTION Action
1 RECORD SNAPSHOT DATA TO UTILIZE WITH REPEATABILITY VERIFICATION 
NOTE:
  • Recording can be facilitated using the screen capture function of the PC.
  • Record the snapshot data on the repair order.
- Go to the next Step.
2 VERIFY IF SNAPSHOT DATA IS AFFECTED BY OTHER RELATED DTCs OCCURRING 
Yes Go to the applicable DTC inspection.
(See DTC C101B:1C [EVP CONTROL UNIT] .)
No Go to the next Step.
3 DETERMINE IF MALFUNCTION CAUSE IS VACUUM SENSOR 1 POWER SUPPLY CIRCUIT OR SIGNAL CIRCUIT 
  • Verify the following items with regard to the recorded snapshot data from Step 1.
    • VS1 V
    • VPWR
  • Are snapshot data VS1_V and VPWR within specification?
Specification: 
VS1 V: Approx. 5 V
VPWR: 8.3-17.4 V
Yes Go to the next Step.
No If DTC C101B:16 is stored: 
  • Go to Step 8.

    If DTC C101B:17 is stored: 

  • Go to Step 12.
4 DETERMINE WHETHER MALFUNCTION IS PAST OR PRESENT 
  • Switch the ignition ON (engine off).
  • Access the VS1 and VS2 PIDs using the MMDS.
  • Compare the values of PIDs VS1 and VS2.
  • Is the difference between PIDs VS1 and VS2 5 kPa {38 mmHg, 2 inHg} or more?
Yes If DTC C101B:16 is stored: 
  • Go to Step 8.
If DTC C101B:17 is stored: 
  • Go to Step 12.
No Go to the next Step.
5 VERIFY DTC REPEATABILITY 
  • Switch the ignition ON (engine off).
  • Access the VS1 PID using the M-MDS.
  • Does the value in PID VS1 change when the wiring harnesses for vacuum sensor 1 is shaken?
Yes If DTC C101B:16 is stored: 
  • Go to Step 8.
If DTC C101B:17 is stored: 
  • Go to Step 12.
No Go to the next Step.
6 DRIVE VEHICLE THEN VERIFY DTC REPEATABILITY BASED ON SERVICE QUESTIONING RESULTS AND SNAPSHOT DATA 
  • Switch the ignition ON (engine off).
  • Access the VS1 PID using the M-MDS.
  • Drive the vehicle based on the service questions content and snapshot data driving conditions.
  • Is the VS1 PID value below 40 kPa {300 mmHg, 11 inHg}, while the vehicle is driven?
Yes Go to the next Step.
No If DTC C101B:16 is stored: 
  • Go to Step 8.
If DTC C101B:17 is stored: 
  • Go to Step 12.
7 VERIFY DTC REPEATABILITY AND DETERMINE IF MALFUNCTION CAUSE IS ELECTRIC VACUUM PUMP CONTROL UNIT 
Yes Replace the EVP control unit, then go to Step 17.
(See EVP CONTROL UNIT REMOVAL/INSTALLATION .)
No DTC troubleshooting completed.
Explain to the customer that there are no malfunctions with the vehicle based on the contents of the servicing.
8 INSPECT VACUUM SENSOR 1 CONNECTOR CONDITION 
  • Switch the ignition OFF.
  • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Disconnect the vacuum sensor 1 connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is the connector normal?
Yes Go to the next Step.
No Repair or replace the connector and/or terminals, then go to Step 16.
9 INSPECT VACUUM SENSOR 1 SIGNAL CIRCUIT FOR SHORT TO GROUND CIRCUIT 
  • Verify that the vacuum sensor 1 connector is disconnected.
  • Inspect for continuity between vacuum sensor 1 terminal C (wiring harness-side) and body ground.
  • Is there continuity?
Yes Disconnect the EVP control unit connector and inspect the wiring harness for short to ground.
  • If the short to ground circuit could be detected in the wiring harness:
  • Refer to the wiring diagram and verify whether or not there is a common connector between vacuum sensor 1 terminal C and EVP control unit terminal AC.
If there is a common connector: 
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground circuit.
  • Repair or replace the malfunctioning part.
If there is no common connector: 
  • Repair or replace the wiring harness which has a short to ground circuit.
  • If the short to ground circuit could not be detected in the wiring harness:

Go to Step 16.
No Go to the next Step.
10 INSPECT EVP CONTROL UNIT CONNECTOR CONDITION 
  • Disconnect the EVP control unit connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is the connector normal?
Yes Go to the next Step.
No Repair or replace the connector and/or terminals, then go to Step 16.
11 INSPECT VACUUM SENSOR 1 POWER SUPPLY AND GROUND CIRCUIT FOR OPEN CIRCUIT 
  • Verify that the vacuum sensor 1 and EVP control unit connectors are disconnected.
  • Inspect for continuity as followings (wiring harness-side):
    • Vacuum sensor 1 terminal A-EVP control unit terminal AA
    • Vacuum sensor 1 terminal B-EVP control unit terminal Y
  • Is there continuity?
Yes Replace the power brake unit, then go to Step 16. (Vacuum sensor 1 malfunction)
(See POWER BRAKE UNIT REMOVAL/INSTALLATION .)
No Refer to the wiring diagram and verify whether or not there is a common connector in the followings:
  • Vacuum sensor 1 terminal A-EVP control unit terminal AA
  • Vacuum sensor 1 terminal B-EVP control unit terminal Y
If there is a common connector: 
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
  • Repair or replace the malfunctioning part.
If there is no common connector: 
  • Repair or replace the wiring harness which has an open circuit. Go to Step 16.
12 INSPECT VACUUM SENSOR 1 CONNECTOR CONDITION 
  • Switch the ignition OFF.
  • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Disconnect the vacuum sensor 1 connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is the connector normal?
Yes Go to the next Step.
No Repair or replace the connector and/or terminals, then go to Step 16.
13 INSPECT VACUUM SENSOR 1 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY 
  • Verify that the vacuum sensor 1 connector is disconnected.
  • Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Switch the ignition ON (engine off).
  • Measure the voltage at the vacuum sensor 1 terminal C (wiring harness-side)-body ground.
  • Is the voltage 5 V or more?
Yes Refer to the wiring diagram and verify whether or not there is a common connector between vacuum sensor 1 terminal C and EVP control unit terminal AC.
If there is a common connector: 
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.
  • Repair or replace the malfunctioning part.
If there is no common connector: 
  • Repair or replace the wiring harness which has a short to power supply.

Go to Step 16.
No Go to the next Step.
14 INSPECT EVP CONTROL UNIT CONNECTOR CONDITION 
  • Switch the ignition OFF.
  • Disconnect the negative battery terminal.

    (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)

  • Disconnect the EVP control unit connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is the connector normal?
Yes Go to the next Step.
No Repair or replace the connector and/or terminals, then go to Step 16.
15 INSPECT VACUUM SENSOR 1 SIGNAL CIRCUIT FOR OPEN CIRCUIT 
  • Verify that the vacuum sensor 1 and EVP control unit connectors are disconnected.
  • Inspect for continuity between vacuum sensor 1 terminal C (wiring harness-side) and EVP control unit terminal AC (wiring harness-side).
  • Is there continuity?
Yes Replace the power brake unit, then go to the next Step. (Vacuum sensor 1 malfunction)
(See POWER BRAKE UNIT REMOVAL/INSTALLATION .)
No Refer to the wiring diagram and verify whether or not there is a common connector between vacuum sensor 1 terminal C and EVP control unit terminal AC. If there is a common connector: 
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
  • Repair or replace the malfunctioning part.
If there is no common connector: 
  • Repair or replace the wiring harness which has an open circuit. Go to the next Step.
16 VERIFY DTC TROUBLESHOOTING COMPLETED 
Yes Repeat the inspection from Step 1.
If the malfunction recurs, replace the EVP control unit, then go to the next Step.
(See EVP CONTROL UNIT REMOVAL/INSTALLATION .)
No Go to the next Step.
17 VERIFY NO DTC IS PRESENT 
  • Are any DTCs present?
Yes Go to the applicable DTC inspection. (See DTC TABLE [EVP CONTROL UNIT] .)
No DTC troubleshooting completed.