SFI SYSTEM, Diagnostic DTC:P1604

DTC Code DTC Name
P1604 Startability Malfunction

DESCRIPTION

This DTC is stored when the engine does not start even though the STA signal is input or when the engine takes a long time to start, and when the engine speed is low or the engine stalls just after the engine starts.

Using the GTS, the conditions present when the DTC was stored can be confirmed by referring to the freeze frame data. Freeze frame data records engine conditions when a malfunction occurs. This information can be useful when troubleshooting.

It is necessary to check if the vehicle ran out of fuel before performing troubleshooting, as this DTC is also stored when there is engine starting trouble due to running out of fuel.

DTC No. Detection Item DTC Detection Condition MIL Memory
P1604 Startability Malfunction

Either conditions is met:


  • The engine speed is below 500 rpm with the STA signal on for a certain amount of time (refer to the illustration below) (1 trip detection logic).

  • After the engine starts (engine speed is 500 rpm or more), the engine speed drops to 200 rpm or less within approximately 2 seconds (1 trip detection logic).

 Does not come on DTC stored
B0026W0E09
Trouble Area
Ignition system

  • Spark plug

  • Ignition coil assembly
Fuel system

  • Fuel injector assembly

  • Fuel pump

  • Fuel pump control circuit

  • Fuel pressure regulator assembly

  • Fuel line

  • Purge VSV system

  • Fuel quality (existence of foreign matter, degradation)
Intake and exhaust systems

  • Mass air flow meter sub-assembly

  • Intake system

    (Air leaks or deposit accumulation)

  • Throttle body with motor assembly

  • Air fuel ratio sensor

  • Heated oxygen sensor

  • Camshaft timing oil control assembly

  • Variable Valve Timing system (VVT system)

  • Brake booster assembly
Other control systems

  • ECM

  • Wire harness or connector

  • Knock control sensor

  • Engine coolant temperature sensor
Engine

  • Thermostat

  • Engine assembly

  • Engine mount
High load from another system

  • Air conditioning system

  • Power steering system

  • Electrical load signal system

CAUTION / NOTICE / HINT

Tech Tips


  • In contrast to normal malfunction diagnosis for components, circuits and systems, DTC P1604 is used to determine the malfunctioning area from the problem symptoms and freeze frame data when the user mentions problems such as starting difficulty.

    As this DTC can be stored as a result of certain user actions, even if the DTC is output, if the customer makes no mention of problems, clear the DTC without performing any troubleshooting and return the vehicle to the customer.

  • If any other DTCs are output, perform troubleshooting for those DTCs first.

  • When this Data List item "Immobiliser Fuel Cut" is ON, the engine cannot be started.

  • Read freeze frame data using the GTS. Freeze frame data records engine conditions when a malfunction occurs. This information can be useful when troubleshooting.

  • When confirming the freeze frame data, be sure to check all 5 sets of freeze frame data.

    Click here

  • When confirming the freeze frame data, if there are multiple items related to the cause of the malfunction, perform troubleshooting for all related items.

  • Try to start the vehicle under the conditions recorded in the freeze frame data which were present when the malfunction occurred. Confirm the data at this time and compare it with the freeze frame data.

  • If the malfunction does not recur, carefully check the vehicle conditions from when the malfunction occurred using freeze frame data.

  • When performing inspections, jiggle the relevant wire harnesses and connectors in an attempt to reproduce malfunctions that do not always occur.

  • If the same inspection or replacement procedure appears 2 times when performing an inspection procedure, it is not necessary to repeat the procedure the second time.

PROCEDURE


  1. CHECK FOR ANY OTHER DTCS OUTPUT


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.


      Powertrain > Engine > Trouble Codes

    5. Read the DTCs.

      Result
      Result Proceed to
      DTC P1604 is output A
      DTC P1604 and other DTCs are output B

      Tech Tips


      • If any DTCs other than P1604 are output, troubleshoot those DTCs first.

      • Using freeze frame data, confirm the conditions the moment the DTC was stored and after the DTC was stored. This information can be useful when troubleshooting.


    B

    GO TO DTC CHART Click here

    A

  2. READ FREEZE FRAME DATA (ISC LEARNING VALUE)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Using the GTS, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored.

      Click here

      Result
      Freeze Frame Data Item Result Suspected Area Action Proceed to
      ISC Learning Value Less than 5.6 L/s - Go to the next step A
      5.6 L/s or higher Throttle valve assembly Go to ENGINE DIFFICULT TO START (from step 15) B

    B

    GO TO ENGINE DIFFICULT TO START Click here

    A

  3. READ FREEZE FRAME DATA (ENGINE SPEED)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Using the GTS, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored.

      Click here

      Result
      Freeze Frame Data Item Result Suspected Area Action Proceed to
      Engine Speed All 5 sets of freeze frame data are 0 rpm (engine did not crank or engine speed was not detected properly)

      • Starter signal circuit

      • Crankshaft position sensor system

      • Battery fully depleted

      		 Go to ENGINE DIFFICULT TO START (from step 5) A
      100 to 500 rpm (engine cranked but initial combustion did not occur or was delayed)

      • Fuel pump

      • Leaking fuel injector assembly

      • Spark plug

      • Ignition coil assembly

      		 Go to the next step B

      500 rpm or higher (engine speed dropped immediately after initial combustion)

      (Low Rev for Eng Start is ON)

      • Spark plug

      • Ignition coil assembly

    A

    GO TO ENGINE DIFFICULT TO START Click here

    B

  4. INTERVIEW THE CUSTOMER


    1. Interview the customer for details about the conditions when the malfunction occurred.

      Tech Tips

      If the engine is difficult to start only when the vehicle has been left as is for a long time, a leaking fuel injector assembly is suspected.

      Result
      Result Suspected Area Action Proceed to
      Engine is difficult to start only when the vehicle has been left as is for a long time (1 hour or more) Leaking fuel injector assembly Go to ENGINE DIFFICULT TO START (from step 4) A
      Other than above

      • Fuel pump

      • Spark plug

      • Ignition coil assembly

      		 Go to the next step B

    A

    GO TO ENGINE DIFFICULT TO START Click here

    B

  5. INTERVIEW THE CUSTOMER


    1. Interview the customer for details about the conditions when the malfunction occurred.

      Tech Tips

      If the vehicle is mostly driven for short distances, deposits may have accumulated on the spark plugs, causing starting difficulty.

      Result
      Result Suspected Area Action Proceed to
      Mostly driven short distances

      • Spark plug

      • Ignition coil assembly

      		 Go to ENGINE DIFFICULT TO START (from step 13) NEXT
      Not mostly driven short distances

      • Fuel pump

      • Spark plug

      • Ignition coil assembly

      		 Go to ENGINE DIFFICULT TO START (from step 9)

    NEXT

    GO TO ENGINE DIFFICULT TO START Click here