Dtc P1605 Rough Idling


DESCRIPTION

INSPECTION PROCEDURE

DTC OUTPUT (RECORD STORED DTC AND FREEZE FRAME DATA (PROCEDURE 1))

CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P1605)

DETERMINE CAUSE OF PROBLEM (CHECK FREEZE FRAME DATA)

DTC P1605 Rough Idling


DESCRIPTION

This DTC is stored if the combustion state of any cylinder is unstable. 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.

P1605
DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
-
When idling with the accelerator pedal released and the vehicle stopped, this item detects when the combustion is unstable from the sudden changes in engine speed between the cylinders. Detection for 2 to 10 seconds according to the combustion state.
(1 trip detection logic).
  1. Injector assembly
  2. Injector compensation code
  3. Fuel leak
  4. Glow system
  5. Intake air system leakage
  6. Intake air system blockage
  7. EGR system
  8. Throttle valve system
  9. Pre-stroke control valve
  10. Low quality fuel
  11. Fuel filter element assembly air bleed problem
  12. Accessory problem (A/C, generator, etc.)
  13. Engine assembly
  14. ECM

Related Data List
DTC No.
Data List
P1605
  1. Target Idle Engine Speed
  2. Engine Speed
  3. MAP
  4. MAF
  5. Coolant Temp
  6. Battery Voltage
  7. Engine Speed of Cyl #1 (to #4)
    (Output only when the "Check the Cylinder Compression" Active Test is performed)
  8. Intake Air
  9. Target Common Rail Pressure
  10. Common Rail Pressure
  11. Injection Feedback Val #1 (to #4)
  12. Injection Volume
  13. Actual Throttle Position
  14. Target EGR Valve Pos
  15. Actual EGR Valve Pos
  16. EGR Close Lrn. Val.
  17. Rough Idle #1 (to #4)
  18. Plural Cylinders Rough Idle

INSPECTION PROCEDURE


In order for idling to be stable, glow system operation, fuel system operation and compression sufficient to maintain the target idling speed are necessary.

Glow system

  1. The following malfunctions may be present in the glow system.

    1. Engine coolant temperature sensor malfunction.

    2. Glow plug assembly malfunction.

    3. Glow plug controller malfunction.


Fuel system

  1. The following malfunctions may be present in the fuel system.

    1. Fuel leakage.

    2. Problem with injector assemblies.

    3. Problem with fuel supply pump assembly.

    4. Air in fuel pipe.


Engine assembly

  1. The following malfunctions may be present in the engine assembly.

    1. Insufficient compression.

HINT:
  1. In contrast to conventional DTCs for components, circuits and systems, DTC P1605 is used to estimate the malfunctioning area from problem symptoms and freeze frame data in response to symptoms such as "rough idling", "strong engine vibrations", etc. Such problem symptoms can occur even in the following conditions:
    1. Driving with long-stored fuel (fuel that has remained in the tank for long periods of time)
    2. Using fuel not acclimated to the climate during a change of seasons
    3. Temporarily using low-quality fuel (fuel that contains water or has poor fuel properties)
  2. If any other DTCs are output, perform troubleshooting for those DTCs first.
  3. Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.
  4. When confirming the freeze frame data, be sure to check all 5 sets of freeze frame data.
1.DTC OUTPUT (RECORD STORED DTC AND FREEZE FRAME DATA (PROCEDURE 1))

  1. Connect the GTS to the DLC3.

  1. Turn the engine switch on (IG) and turn the GTS on.

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

  1. Record the stored DTC and freeze frame data.

    HINT:
    This freeze frame data shows the actual engine conditions when air fuel ratio too rich trouble occurred.

NEXT


2.CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P1605)

  1. Connect the GTS to the DLC3.

  1. Turn the engine switch on (IG) and turn the GTS on.

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

  1. Read the DTCs.

    Result
    Result
    		Proceed to
    DTC P1605 is output
    		A
    DTC P1605 and other DTCs are output
    		B

    HINT:
    If any DTCs other than P1605 are output, troubleshoot those DTCs first.


B
GO TO DTC CHART (LandCruiser RM0000031HW07PX.html)
A


3.DETERMINE CAUSE OF PROBLEM (CHECK FREEZE FRAME DATA)

  1. Determine the cause of the problem based on the freeze frame data recorded in Procedure 1.

    Rough Idle #1 to #4
    Judgment of Data List Values
    		Problem Cause
    		Diagnosis Note
    		Proceed to
    Any of Rough Idle #1 to #4 in the freeze frame data is ON
    		Injector assembly
    		If the cylinder that displays Rough Idle ON also has a value of more than 3.0 mm3/st for Injection Feedback Val, improper combustion in that cylinder is suspected.
    HINT:
    When there are temporary changes in the injection characteristics, the malfunction may not be indicated by the value for Injection Feedback Val in the freeze frame data.
    		A

    Injection Feedback Val #1(to #4)
    Judgment of Data List Values
    		Problem Cause
    		Diagnosis Note
    		Proceed to
    Any of Injection Feedback Val #1 to #4 in the freeze frame data is more than 3.0 mm3/st
    		Injector assembly
    		If the cylinder that displays Rough Idle ON also has a value of more than 3.0 mm3/st for Injection Feedback Val, improper combustion in that cylinder is suspected.
    		A

    Plural Cylinders Rough Idle:
    Judgment of Data List Values
    		Problem Cause
    		Diagnosis Note
    		Proceed to
    Plural Cylinders Rough Idle in the freeze frame data is ON
    1. EGR system
    2. Diesel throttle system
    3. Fuel supply pump assembly
    4. Low-quality fuel
    		When EGR Rate Differential (Actual-Target) increases by more than 30%, there may be a malfunction in the EGR system.
    		B
    When there is data stored that indicates that Common Rail Pressure is low compared to Target Common Rail Pressure, there may be a malfunction in the fuel pressure control system, such as in the fuel supply pump assembly.
    		C
    When data indicating that MAP is low (50 kPa or less) is stored, there may be a stuck closed malfunction in the diesel throttle system or EGR valve.
    		-



B
GO TO CHECK DATA LIST (ACTUAL EGR VALVE/TARGET EGR VALVE DIFFERENTIAL) (ROUGH IDLING OR EXCESSIVE ENGINE VIBRATIONS)

C
GO TO CHECK DATA LIST (COMMON RAIL PRESSURE AND TARGET COMMON RAIL PRESSURE) (ROUGH IDLING OR EXCESSIVE ENGINE VIBRATIONS)
A

GO TO INSPECT INJECTOR COMPENSATION CODE (ROUGH IDLING OR EXCESSIVE ENGINE VIBRATIONS) (LandCruiser RM000000W0C0FJX.html)