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Pinpoint Test I: DTCs C109D, C109E and C109F




Anti-Lock Control

Pinpoint Test I: DTCs C109D, C109E and C109F


Normal Operation

The ABS module uses the vacuum sensor to determine if hydraulic pump intervention is necessary due to a severe loss of vacuum in the booster. The ABS module sends a 5-volt reference voltage to the sensor and the sensor compares the pressure in the booster to the ambient air pressure in the engine compartment and sends a varying voltage back to the ABS module based on the difference between the pressures. Normally, the pressure in the booster is much lower than ambient air pressure. As the pressure in the booster gets higher (closer to matching ambient air pressure), the lower the voltage sent back to the ABS module becomes.

When the vacuum in the brake booster falls severely below a predetermined level, the ABS module commands the hydraulic pump motor to activate on the next (and any subsequent) brake pedal application (with any vehicle speed) to assist with vehicle braking. The ABS module continues to use the pump motor for braking assist as long as the low vacuum condition exists. Only the 3.5L engine uses an auxiliary vacuum pump to supplement the brake booster vacuum level when it is low. It assists the vacuum booster when vacuum levels drop below 57.56 kPa (17 in-Hg) of vacuum. DTCs set in the ignition cycle can only be cleared by cycling the ignition off and on once the fault has been corrected.

- DTC C109D (Low Vacuum Condition Detected)- this DTC sets in continuous memory and every ignition cycle when the optimized hydraulic brake system is activated and does not necessarily indicate a concern with the vacuum sensor, the related wiring or the ABS module. This DTC indicates a vacuum concern in the brake booster, engine and any related vacuum hoses/tubes. High altitude locations with low ambient air temperatures can cause a low vacuum condition to exist in the booster until the engine compartment warms up.

- DTC C109E (Vacuum Sensor Circuit Fault)- this DTC sets in continuous memory and every ignition cycle if during normal operation or the ABS module on-demand self-test, the ABS module detects an open circuit, a short to voltage or a short to ground on the vacuum sensor circuits or a failure of the vacuum sensor.

- DTC C109F (Vacuum Sensor Signal Fault)- this DTC sets in continuous memory and every ignition cycle if the vacuum sensor ambient air pressure inlet ports, or the vacuum sensor ports become restricted or clogged.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Vacuum sensor

- ABS module

PINPOINT TEST I : DTCs C109D, C109E AND C109F

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

I1 CHECK THE ABS MODULE DTCs

- Review the DTCs recorded during Inspection and Verification.

Was DTC C109D the only recorded DTC?

Yes
GO to I2.
No
If DTC C109E and/or C109F was retrieved, GO to I6.

For all other DTCs, REFER to the ABS Module DTC Chart. Anti-Lock Brake System (ABS) and Stability Control

I2 CHECK DTC RETURNABILITY

- Using the scan tool, clear the ABS module DTCs.

- Ignition OFF.

- Disconnect the scan tool.

- Start the engine.

- NOTE: It may take up to 3 minutes for DTC C109D to set.

Allow the vehicle to idle for a minimum of 4 minutes. Apply and release the brake pedal for a minimum of 3 times per minute with normal pedal force for up to 3 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 I3.
No
If DTC C109E and/or C109F was retrieved, GO to I6.

For all other DTCs, REFER to the ABS Module DTC Chart. Anti-Lock Brake System (ABS) and Stability Control

If no DTC is set, the system is operating correctly as this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTC. REPEAT the self-test.

I3 CHECK THE ENGINE VACUUM

- Carry out the Intake Manifold Vacuum Test, refer to Diagnosis and Testing in Engine. Intake Manifold Vacuum Test

- Record the vacuum reading.

Does the vacuum gauge indicate normal vacuum?

Yes
GO to I4.
No
FOLLOW the diagnostic procedure in Engine.

I4 CHECK THE BRAKE BOOSTER

- Carry out the Brake Booster Component Test. Component Tests

Do the brake booster and check valve pass the component test?

Yes
GO to I5.
No
REPAIR or INSTALL new as necessary. CLEAR the DTC. REPEAT the self-test.

I5 CHECK THE BRAKE BOOSTER VACUUM LEVEL (BBVACLVL) 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 the brake booster vacuum level PID.

Does the PID match the recorded vacuum reading of ±3.386 kPa (1 in-Hg)?

Yes
REPAIR any vacuum leaks at the vacuum system. For 4x4 vehicles, REPAIR any vacuum leaks from the vacuum hub lock system. REPEAT the ABS module self-test.
No
INSTALL a new brake booster vacuum sensor. CLEAR the DTCs. TEST the system for normal operation.

I6 CHECK THE BRAKE BOOSTER VACUUM SENSOR

- Inspect the vacuum sensor ambient air pressure inlet ports.

Are both ports free of contamination, debris and/or foreign material?

Yes
GO to I7.
No
REPAIR or INSTALL a new vacuum sensor as necessary. CLEAR the DTCs. REPEAT the self-test.

I7 CHECK THE BRAKE BOOSTER VACUUM SENSOR CIRCUITS FOR A SHORT TO GROUND

- Disconnect: ABS Module C135.

- Disconnect: Brake Booster Vacuum Sensor C149.

- Measure the resistance between ground and:
- brake booster vacuum sensor C149-1, circuit VCA22 (GN/BN), harness side.

- brake booster vacuum sensor C149-2, circuit GD120 (BK/GN), harness side.

- brake booster vacuum sensor C149-3, circuit CCA22 (GY/YE), harness side.







Is the resistance greater than 10,000 ohms?

Yes
GO to I8.
No
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.

I8 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 C149, harness side as follows:

ABS Module Circuit Vacuum Sensor C135-10 VCA22 (GN/BN) C149-1 C135-28 GD120 (BK/GN) C149-2 C135-2 CCA22 (GY/YE) C149-3








Are the resistances less than 5 ohms?

Yes
GO to I9.
No
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.

I9 CHECK THE BRAKE BOOSTER VACUUM SENSOR CIRCUITS FOR A SHORT TOGETHER

- Measure the resistance between:
- brake booster vacuum sensor C149-1, circuit VCA22 (GN/BN), harness side and brake booster vacuum sensor C149-2, circuit GD120 (BK/GN), harness side.

- brake booster vacuum sensor C149-1, circuit VCA22 (GN/BN), harness side and brake booster vacuum sensor C149-3, circuit CCA22 (GY/YE), harness side.

- brake booster vacuum sensor C149-2, circuit GD120 (BK/GN), harness side, and brake booster vacuum sensor C149-3, circuit CCA22 (GY/YE), harness side.







Are the resistances greater than 10,000 ohms?

Yes
GO to I10.
No
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.

I10 CHECK THE ACTIVE BRAKE BOOSTER VACUUM SENSOR CIRCUITS FOR A SHORT TO VOLTAGE

- Ignition ON.

- Measure the voltage between ground and:
- brake booster vacuum sensor C149-1, circuit VCA22 (GN/BN), harness side.

- brake booster vacuum sensor C149-2, circuit GD120 (BK/GN), harness side.

- brake booster vacuum sensor C149-3, circuit CCA22 (GY/YE), harness side.







Is any voltage present?

Yes
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
No
GO to I11.

I11 CHECK THE BRAKE BOOSTER VACUUM SENSOR CONNECTOR

- Ignition OFF.

- Check brake booster vacuum sensor connector for:
- corrosion

- damaged pins

- pushed-out pins


- Connect: Brake Booster Vacuum Sensor C149.

- 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 vacuum sensor. CLEAR the DTCs. REPEAT the self-test.

If DTC C109E or C109F return, GO to I12.
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.

I12 CHECK THE ABS MODULE CONNECTORS

- Ignition OFF.

- Disconnect: ABS Module C135.

- Check ABS module connector for:
- corrosion

- damaged pins

- pushed-out pins


- 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 . 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.

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