ECD SYSTEM, Diagnostic DTC:P1674

DTC Code DTC Name
P1674 Solenoid for Exhaust Brake Circuit Malfunction

DESCRIPTION

The exhaust brake VSV, mounted on the exhaust retarder, opens and closes according to the signals from the ECM. The ECM receives the signals from the clutch switch and exhaust retarder switch. Through the brake VSV, the ECM controls the negative pressure applied to the diaphragm in the retarder.

DTC No. DTC Detection Condition Trouble Area
P1674 Open or short in exhaust brake solenoid circuit for more than 3 seconds with clutch pedal released

  • Open or short in exhaust brake solenoid circuit

  • Exhaust brake solenoid

  • ECM

WIRING DIAGRAM

A01CH83E01

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE


  1. CHECK ECM (EXB VOLTAGE)


    1. A01CGXCE11

      Turn the ignition switch to the ON position.

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

      Standard voltage
      Tester Connection Condition Specified Condition
      E23-8 (EXB) - E23-7 (E1) Exhaust brake is operating 18 to 27 V

    NG

    INSPECT EXHAUST BRAKE VALVE ASSEMBLY Click here

    OK

    REPLACE ECM

  2. INSPECT EXHAUST BRAKE VALVE ASSEMBLY


    1. A01CIEFE01

      Remove the exhaust brake solenoid.

    2. Check operation of the exhaust brake solenoid.

      Result
      Port Connection Specified Condition
      A - B Air does not flow
      A - B

      Air flows

      (when battery voltage is applied to terminals 1 and 2)
      A - C Air flows
      A - C

      Air does not flow

      (when battery voltage is applied to terminals 1 and 2)

    NG

    REPLACE EXHAUST BRAKE VALVE ASSEMBLY

    OK

  3. CHECK HARNESS AND CONNECTOR (ECM - EXHAUST BRAKE VALVE ASSEMBLY)


    1. A01CGS4E01

      Disconnect the exhaust brake solenoid connector.

    2. Disconnect the ECM connector.

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

      Standard resistance
      Check for open
      Tester Connection Condition Specified Condition
      V6-1 - E23-8 (EXB) Always Below 1 Ω
      Check for short
      Tester Connection Condition Specified Condition
      V6-1 or E23-8 (EXB) - Body ground Always 10 kΩ or higher

    4. Reconnect the exhaust brake solenoid connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - EXHAUST BRAKE VALVE ASSEMBLY)

    OK

    REPLACE ECM