Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: Rough Idling (P160500)

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual / Engine & Hybrid System / 2gr-fks (engine Control) / Sfi System / Rough Idling (P160500)

DESCRIPTION

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

Using the Techstream, 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 idling is unstable due to running out of fuel.

DTC No.

Detection Item

DTC Detection Condition

MIL

Memory

Note

P160500

Rough Idling

When idling with the accelerator pedal released and the vehicle stopped, this item detects when the combustion is worsening at predetermined levels from the changes in engine speed between the cylinders.

Detection for 2 to 10 seconds according to the combustion state (1 trip detection logic).

Does not come on

DTC stored

SAE Code: P1605

Trouble Area

Ignition system
  • Spark plug
  • Ignition coil assembly

Fuel system
  • Fuel injector assembly (for port injection)
  • Fuel injector assembly (for direct injection)
  • Fuel pump (for low pressure side)
  • Fuel pump assembly (for high pressure side)
  • Fuel pump control circuit
  • 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
  • Cam timing oil control solenoid assembly
  • Camshaft timing oil control valve assembly
  • Variable Valve Timing system (VVT system)

Other control systems
  • ECM
  • Wire harness or connector
  • Knock control sensor
  • Engine coolant temperature sensor

Engine
  • Water inlet with thermostat sub-assembly
  • Engine assembly

High load from another system
  • Air conditioning system
  • Power steering system
  • Electrical load signal system
  • A/T system

CAUTION / NOTICE / HINT

HINT:

  • DTC P160500
    • In contrast to conventional DTCs for components, circuits and systems, DTC P160500 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:

      • Driving with long-stored fuel (fuel that has remained in the tank for long periods of time)
      • Using fuel not acclimated to the climate during a change of seasons
      • Temporarily using low-quality fuel (fuel that contains water or has poor fuel properties)
    • As DTCs may be stored when an Active Test or learning is performed, make sure to clear the DTCs before returning the vehicle to the customer.
    • If any other DTCs are output, perform troubleshooting for those DTCs first.
  • FREEZE FRAME DATA
    • Read freeze frame data using the Techstream. 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 multi 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 operate 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 the data when the engine is idling (engine warmed up, no load, and shift lever in D or N) and compare this data with the freeze frame data.
  • PRECAUTIONS
    • Inspections take into account the fact that the malfunction may not have recurred and place emphasis on checking the vehicle conditions present at the time when the malfunction occurred.
    • When performing inspections, jiggle the relevant wire harnesses and connectors in an attempt to reproduce malfunctions that do not always occur.

PROCEDURE

1.

CHECK FOR ANY OTHER DTCS OUTPUT

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read the DTCs.

Powertrain > Engine > Trouble Codes

Result

Proceed to

Only DTC P160500 is output

A

DTCs other than P160500 are output

B

HINT:

  • If any DTCs other than P160500 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

A

2.

READ FREEZE FRAME DATA

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Using the Techstream, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored.

Click here

Freeze Frame Data Item for DTC P160500

Suspected Area

Action

Proceed to
  • Rough Idle Cylinder #1 to #6
  • Plural Cylinders Rough Idle

Compression Leakage Count

"One of Rough Idle Cylinder #1 to #6 is ON"

and

"Plural Cylinders Rough Idle is OFF"

4 or less
  • Spark plug
  • Ignition coil assembly
  • Fuel injector assembly (port or direct)

Go to ROUGH IDLING (from step 7)

A

Plural Cylinders Rough Idle is ON

4 or less
  • Mass air flow meter sub-assembly
  • Fuel injector assembly (port or direct)
  • Fuel system (low or high pressure)
  • Air fuel ratio sensor

Go to ROUGH IDLING (from step 15)

B

"One of Rough Idle Cylinder #1 to #6 are ON"

or

"Plural Cylinders Rough Idle is ON"

5 or more

Pressure loss from valve damage, deposits jamming the valve etc.

Check compression and clean deposits in combustion chamber and intake system.

C
B

GO TO STEP 4

C

GO TO STEP 5

A

3.

DETERMINE CAUSE OF MALFUNCTION FOR INDIVIDUAL CYLINDER

(a) Perform troubleshooting from Rough Idling step 7 (PERFORM ACTIVE TEST USING TECHSTREAM (CHECK THE CYLINDER COMPRESSION) and onward.

Click here

NEXT

GO TO ROUGH IDLING

4.

DETERMINE CAUSE OF MALFUNCTION FOR MULTIPLE OR ALL CYLINDERS

(a) Perform troubleshooting from Rough Idling step 15 (READ VALUE USING TECHSTREAM (MASS AIR FLOW SENSOR)) and onward.

Click here

NEXT

GO TO ROUGH IDLING

5.

PERFORM ACTIVE TEST USING TECHSTREAM (CHECK THE CYLINDER COMPRESSION)

(a) Warm up the engine.

(b) Turn the engine switch off.

(c) Connect the Techstream to the DLC3.

(d) Turn the engine switch on (IG).

(e) Turn the Techstream on.

(f) Enter the following menus: Powertrain / Engine / Active Test / Check the Cylinder Compression / Data List / Compression / Engine Speed Cylinder #1 to #6 and Average Engine Speed of All Cylinder.

Powertrain > Engine > Active Test

Active Test Display

Check the Cylinder Compression

Data List Display

Engine Speed Cylinder #1

Engine Speed Cylinder #2

Engine Speed Cylinder #3

Engine Speed Cylinder #4

Engine Speed Cylinder #5

Engine Speed Cylinder #6

Average Engine Speed of All Cylinder

HINT:

To display the entire Data List, press the pull down menu button next to Primary. Then select Compression.

(g) Push the snapshot button to turn the snapshot function on.

HINT:

Using the snapshot function, data can be recorded during the Active Test.

(h) While the engine is not running, press the Active test button to change Check the Cylinder Compression to "Start".

HINT:

After performing the above procedure, Check the Cylinder Compression will start. Fuel injection for all cylinders is prohibited and each cylinder engine speed measurement enters standby mode.

(i) Crank the engine for about 10 seconds.

(j) Monitor the engine speed (Engine Speed Cylinder #1 to #6 and Average Engine Speed of All Cylinder) displayed on the Techstream.

HINT:

  • At first, the Techstream displays extremely high cylinder engine speed values. After approximately 10 seconds of engine cranking, each cylinder engine speed measurement will change to the actual engine speed.
  • If the cylinder engine speed values (Engine Speed Cylinder #1 to #6) displayed in the Data List do not change from an extremely high value, return to the Active Test menu screen, change "Check the Cylinder Compression" to "Start" and crank the engine again within 1 second.

NOTICE:

  • Do not crank the engine continuously for 20 seconds or more.
  • If it is necessary to crank the engine again after Check the Cylinder Compression has been changed to "Start" and the engine has been cranked once, press Exit to return to the Active Test menu screen. Then change Check the Cylinder Compression to "Start" and crank the engine.
  • Use a fully-charged battery.

(k) Stop cranking the engine, and then change "Check the Cylinder Compression" to "Stop" after the engine stops.

NOTICE:

  • If the Active Test is changed to "Stop" while the engine is being cranked, the engine will start.
  • When performing the Active Test, DTC P160400 (Startability Malfunction) may be stored.
  • After performing the Active Test, make sure to check and clear DTCs.

(l) Push the snapshot button to turn the snapshot function off.

(m) Select "Stored Data" on the Techstream screen, select the recorded data and display the data as a graph.

HINT:

If the data is not displayed as a graph, the change of the values cannot be observed.

(n) Read the value.

HINT:

  • If the value of Data List item "Engine Speed Cylinder #1 to #6" of a cylinder is higher than other cylinders, the cylinder may be malfunctioning.
  • If the value of Data List item "Engine Speed Cylinder #1 to #6" is high for only one cylinder, compression loss is suspected.

Result

Proceed to

There is no variation in "Engine Speed Cylinder #1 to #6"

(All cylinders display approximately the same value for "Engine Speed Cylinder #1 to #6")

A

There is variation in "Engine Speed Cylinder #1 to #6"

(Only one cylinder displays a value for "Engine Speed Cylinder #1 to #6" that differs considerably)

B
A

CLEAN OFF ANY DEPOSITS
B

6.

CHECK CYLINDER COMPRESSION PRESSURE

(a) Measure the cylinder compression pressure. If the compression pressure of a cylinder is low, inspect the engine assembly and repair or replace parts as necessary.

Click here

NEXT

END
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