PINPOINT TEST K: DTCs C109D, C109E AND C109F

WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, and 2011 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

K1 CHECK THE ABS MODULE DTCs
- Review the DTCs recorded during Inspection and Verification.
- Was DTC C109D the only recorded DTC?
- Yes : GO to K2.
- No : If DTC C109E and/or C109F was retrieved, GO to K6. For all other DTCs, REFER to the ABS MODULE DTC TABLE in this service information.
K2 CHECK DTC RETURNABILITY
- Using the scan tool, clear the ABS module DTCs.
- Ignition OFF.
- Disconnect the scan tool.
- Start the engine.
- Allow the vehicle to idle for a minimum of 4 minutes.
- Ignition OFF.
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module.
- Is DTC C109D the only vacuum sensor DTC present?
- Yes : GO to K3.
- No : If DTC C109E and/or C109F was retrieved, GO to K6. For all other DTCs, REFER to the ABS MODULE DTC TABLE in this service information.
K3 CHECK THE ENGINE VACUUM
- Carry out the Intake Manifold Vacuum Test, refer to Diagnosis and Testing in ENGINE SYSTEM - GENERAL INFORMATION article.
- Record the vacuum reading.
- Does the vacuum gauge indicate normal vacuum?
- Yes : GO to K4.
- No : FOLLOW the diagnostic direction as laid out in ENGINE SYSTEM - GENERAL INFORMATION article.
K4 CHECK THE BRAKE BOOSTER
- Carry out the Brake Booster Component Test, refer to Diagnosis and Testing in BRAKE SYSTEM - GENERAL INFORMATION article.
- Do the brake booster and check valve pass the component test?
- Yes : GO to K5.
- No : REPAIR or INSTALL new as necessary. CLEAR the DTC. REPEAT the self-test.
K5 CHECK THE BRAKE BOOSTER VACUUM LEVEL PID
- Connect the scan tool.
- Start the engine.
- Enter the following diagnostic mode on the scan tool: DataLogger - ABS Module.
- Compare the recorded vacuum reading to the brake booster vacuum level PID.
- Does the PID match the recorded vacuum reading?
- Yes : INSTALL a new ABS module. REFER to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE in this service information. TEST The system for normal operation.
- No : INSTALL a new brake booster vacuum sensor. REFER to POWER BRAKE ACTUATION -- BRAKE BOOSTER article. CLEAR the DTCs. TEST the system for normal operation.
K6 CHECK THE BRAKE BOOSTER VACUUM SENSOR
- Inspect the vacuum sensor ambient air pressure inlet ports.
- Are all 4 ports free of contamination and/or foreign material?
- Yes : GO to K7.
- No : REPAIR or INSTALL a new vacuum sensor as necessary. REFER to POWER BRAKE ACTUATION -- BRAKE BOOSTER article. CLEAR the DTCs. REPEAT the self-test.
K7 CHECK THE BRAKE BOOSTER VACUUM SENSOR CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: ABS Module C135.
- Disconnect: Brake Booster Vacuum Sensor C1603.
- Measure the resistance between ground and:
  - brake booster vacuum sensor C1603-1, circuit VCA38 (BN/VT), harness side.
  - brake booster vacuum sensor C1603-2, circuit RCA37 (WH/BU), harness side.
  - brake booster vacuum sensor C1603-3, circuit LCA37 (YE/OG), harness side.
  Fig 1: Checking Brake Booster Vacuum Sensor Circuits For Short To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
- Yes : GO to K8.
- No : REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.

K8 CHECK THE BRAKE BOOSTER VACUUM SENSOR CIRCUITS FOR AN OPEN

Measure the resistance between the ABS module C135, harness side and the brake booster vacuum sensor C1603, harness side as indicated in the following table:

VACUUM SENSOR RESISTANCE TABLE

ABS Module	Circuit	Vacuum Sensor
C135-30	VCA38 (BN/VT)	C1603-1
C135-27	RCA37 (WH/BU)	C1603-2
C135-26	LCA37 (YE/OG)	C1603-3

Fig 2: Checking Brake Booster Vacuum Sensor Circuits For Open

Courtesy of FORD MOTOR CO.

Are the resistances less than 5 ohms?

Yes : GO to K9.
No : REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.

K9 CHECK THE BRAKE BOOSTER VACUUM SENSOR CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between:
  - brake booster vacuum sensor C1603-1, circuit VCA38 (BN/VT), harness side and brake booster vacuum sensor C1603-2, circuit RCA37 (WH/BU), harness side.
  - brake booster vacuum sensor C1603-1, circuit VCA38 (BN/VT), harness side and brake booster vacuum sensor C1603-3, circuit LCA37 (YE/OG), harness side.
  - brake booster vacuum sensor C1603-2, circuit RCA37 (WH/BU), harness side, and brake booster vacuum sensor C1603-3, circuit LCA37 (YE/OG), harness side.
  Fig 3: Checking Brake Booster Vacuum Sensor Circuits For Short Together
  Courtesy of FORD MOTOR CO.
- Are the resistances greater than 10,000 ohms?
- Yes : GO to K10.
- No : REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
K10 CHECK THE ACTIVE BRAKE BOOSTER CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between ground and:
  - brake booster vacuum sensor C1603-1, circuit VCA38 (BN/VT), harness side.
  - brake booster vacuum sensor C1603-2, circuit RCA37 (WH/BU), harness side.
  - brake booster vacuum sensor C1603-3, circuit LCA37 (YE/OG), harness side.
  Fig 4: Checking Active Brake Booster Circuits For Short To Voltage
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
- Yes : REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
- No : GO to K11.
K11 CHECK THE ABS MODULE CONNECTORS
- Check ABS module C135 for:
  - corrosion.
  - pushed-out pins.
  - spread terminals.
- Connect: ABS Module C135.
- Make sure the connector seats correctly, then operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new ABS module. REFER to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE in this service information. TEST the system for normal operation.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.