SFI SYSTEM, Diagnostic DTC:C1476 and C1477

DTC Code DTC Name
C1476 Brake Booster Pressure Sensor Circuit Low
C1477 Brake Booster Pressure Sensor Circuit High

DESCRIPTION

The ECM detects changes in the brake booster assembly pressure based on the voltage signal received from the vacuum sensor assembly installed to the brake booster assembly. If the ECM determines that there is a malfunction in the signal sent by the vacuum sensor assembly, it stores DTC C1476 or C1477.

A370625E01

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

C1476

Brake Booster Pressure Sensor Circuit Low

The vacuum sensor assembly output voltage is 0.5 V or less for 1.2 seconds or more (1 trip detection logic).

  • Open or Short in vacuum sensor assembly circuit

  • Vacuum sensor assembly

  • ECM

Does not come on

DTC stored

C1477

Brake Booster Pressure Sensor Circuit High

The vacuum sensor assembly output voltage is 4.5 V or higher for 1.2 seconds or more (1 trip detection logic).

  • Open or Short in vacuum sensor assembly circuit

  • Vacuum sensor assembly

  • ECM

Does not come on

DTC stored
Tip:

When any of these DTCs are output, check the brake booster pressure by using the GTS. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Brake Boost Pressure Sensor.

Brake Boost Pressure Sensor (V)

Malfunction

0.5 or less

  • Short to ground in PB circuit

  • Short in PB to E2 circuit

  • Open in VC circuit

4.5 or higher

  • Short in PB to VC circuit

  • Open in PB circuit

  • Open in E2 circuit

MONITOR DESCRIPTION

If there is a defect or an open or short circuit in the vacuum sensor assembly, the voltage level deviates from the normal operating range. The ECM interprets this deviation as a malfunction in the vacuum sensor assembly circuit and stores a DTC.

WIRING DIAGRAM

A382203E04

CONFIRMATION DRIVING PATTERN

DTC C1476 and C1477 are detected when the engine idles for 10 seconds or more.

CAUTION / NOTICE / HINT

Note:

After replacing the ECM, perform idle learning.

Click here

Tip:

Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

  1. CHECK HARNESS AND CONNECTOR (VACUUM SENSOR ASSEMBLY - ECM)

    1. Disconnect the vacuum sensor assembly connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

    Standard Resistance

    Tester Connection

    Condition

    Specified Condition

    A15-3 (VC) - A34-56 (BRVC)

    Always

    Below 1 Ω

    A15-2 (PB) - A34-54 (PB)

    Always

    Below 1 Ω

    A15-1 (E2) - A34-55 (BRE2)

    Always

    Below 1 Ω

    A15-3 (VC) or A34-56 (BRVC) - Body ground and other terminals

    Always

    10 kΩ or higher

    A15-2 (PB) or A34-54 (PB) - Body ground and other terminals

    Always

    10 kΩ or higher

    A15-1 (E2) or A34-55 (BRE2) - Body ground and other terminals

    Always

    10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF VACUUM SENSOR ASSEMBLY)

    A428977C01

    *a

    Front view of wire harness connector

    (to Vacuum Sensor Assembly)

    1. Disconnect the vacuum sensor assembly connector.

    2. Turn the ignition switch to ON.

    3. Measure the voltage according to the value(s) in the table below.

    Standard Voltage

    Tester Connection

    Condition

    Specified Condition

    A15-3 (VC) - A15-1 (E2)

    Ignition switch ON

    4.75 to 5.25 V

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE VACUUM SENSOR ASSEMBLY

    Click here

    NG

    REPLACE ECM

    Click here