DTC P0506:00

IAC system RPM lower than expected

DTC P151B:00

IAC system problem

DETECTION CONDITION

DTC P0506:00

• The actual idle speed is lower than expected by 100 rpm for 14 s, when the brake pedal is depressed (brake switch is on).

  NOTE:

  • If the atmospheric pressure is less than 72.2 kPa {0.736 kgf/cm², 10.5 psi} or the intake air temperature is below −10 °C {14 °F}, the PCM cancels the diagnosis of DTC P0506:00.

Diagnostic support note

• This is a continuous monitor (CCM).

• The check engine light illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.

• PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle.

• FREEZE FRAME DATA/Snapshot data is available.

• DTC is stored in the PCM memory.

DTC P151B:00

• The PCM cannot control the idle speed toward the target idle speed during the KOER self test.

Diagnostic support note

• The check engine light does not illuminate.

• FREEZE FRAME DATA is not available.

• Snapshot data is available.

• DTC is stored in the PCM memory.

FAIL-SAFE FUNCTION

Not applicable

POSSIBLE CAUSE

• A/C magnetic clutch malfunction

• Drive-by-wire control system malfunction

• Malfunction in injection amount measurement system (refer to DTC P0101:00)

• Purge solenoid valve malfunction

• Air cleaner element restricted

• Throttle body passage blockage

• Engine malfunction

• Insufficient engine compression

• Generator control circuit malfunction

• PCM malfunction

SYSTEM WIRING DIAGRAM

Not applicable

STEP

INSPECTION

ACTION

1

NOTE:

• Recording can be facilitated using the screen capture function of the PC.

• Record the snapshot data on the repair order.

—

Go to the next step.

2

• Verify related Service Bulletins and/or on-line repair information availability.

• Is any related repair information available?

Yes

Perform repair or diagnosis according to the available repair information.

• If the vehicle is not repaired, go to the next step.

No

Go to the next step.

3

• Switch the ignition off, then ON (engine off).

• Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure.

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• Are any other PENDING CODEs and/or DTCs present?

Yes

Go to the applicable PENDING CODE or DTC inspection.

(See DTC TABLE [PCM (SKYACTIV-G 2.0)].)

No

Go to the next step.

4

• Turn the A/C switch off.

• Is the magnetic clutch still on?

Yes

Perform the symptom troubleshooting “NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”.

(See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [SKYACTIV-G 2.0].)

No

Go to the next step.

5

• Perform the Drive-by-wire Control System Inspection.

  (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Repair or replace the malfunctioning part according to the inspection results, then go to Step 11.

No

Go to the next step.

6

• Perform the Purge Control System Inspection.

  (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Repair or replace the malfunctioning part according to the inspection results, then go to Step 11.

(See PURGE SOLENOID VALVE REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

7

• Remove the air cleaner element with the engine is running.

  (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

• Does the engine speed increase?

Yes

Clean or replace the air cleaner element, then go to Step 11.

(See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

8

• Visually inspect the throttle body passage.

• Is the throttle body passage dirty and/or restricted?

Yes

Clean or replace the throttle body passage, then go to Step 11.

(See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

9

• Inspect the engine compression.

  (See COMPRESSION INSPECTION [SKYACTIV-G 2.0].)

• Are compression pressures within specification?

Yes

Go to the next step.

No

Repair or replace the malfunctioning part according to the inspection results, then go to Step 11.

10

• Apply the electrical load (such as blower fan, rear window defogger, or headlight).

• Does the engine speed increase?

Yes

Go to the next step.

No

Repair or replace the malfunctioning part according to the inspection results, then go to the next step.

11

• Always reconnect all disconnected connectors.

• Clear the DTC from the PCM memory using the M-MDS.

  (See AFTER REPAIR PROCEDURE [PCM (SKYACTIV-G 2.0)].)

• Start the engine and warm it up completely.

• Depress the brake pedal for 14 s or more.

• Perform the KOER self test.

  (See KOEO/KOER SELF TEST [PCM (SKYACTIV-G 2.0)].)

• Perform the Pending Trouble Code Access Procedure.

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• Is the PENDING CODE and/or DTC for this DTC present?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the PCM.

  (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

Go to the next step.

No

Go to the next step.

12

• Perform the “AFTER REPAIR PROCEDURE”.

  (See AFTER REPAIR PROCEDURE [PCM (SKYACTIV-G 2.0)].)

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [PCM (SKYACTIV-G 2.0)].)

No

DTC troubleshooting completed.