NO.9 FAST IDLE/RUNS ON [MZR 1.8, MZR 2.0, MZR 2.5]

9	FAST IDLE/RUNS ON
DESCRIPTION	• Engine speed continues at fast idle after warm-up. • Engine runs after the ignition is off.
POSSIBLE CAUSE	• Cooling system malfunction • ECT sensor malfunction • Improper load signal input ― Refrigerant pressure switch malfunction ― Evaporator temperature sensor malfunction ― Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal) ― CPP switch malfunction (MTX) ― Neutral switch malfunction (MTX) ― TR switch malfunction (ATX) ― Communication error between TCM and PCM (ATX) • Air leakage from intake air system • Improper operation of electronic throttle control system • APP sensor malfunction

FAST IDLE/RUNS ON

DESCRIPTION

• Engine speed continues at fast idle after warm-up.

• Engine runs after the ignition is off.

POSSIBLE CAUSE

• Cooling system malfunction

• ECT sensor malfunction

• Improper load signal input

― Refrigerant pressure switch malfunction

― Evaporator temperature sensor malfunction

― Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal)

― CPP switch malfunction (MTX)

― Neutral switch malfunction (MTX)

― TR switch malfunction (ATX)

― Communication error between TCM and PCM (ATX)

• Air leakage from intake air system

• Improper operation of electronic throttle control system

• APP sensor malfunction

STEP	INSPECTION	RESULTS	ACTION
1	Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.8, MZR 2.0, MZR 2.5].) Start and warm up the engine to normal operating temperature. Is the ECT PID value between 82—112 °C {180—234 °F}?	Yes	Go to the next step.
No	ECT PID value is higher than 112 °C {234 °F}: • Go to the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”. (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR 1.8, MZR 2.0, MZR 2.5].) ECT PID value is less than 82 °C {180 °F}: • Go to the symptom troubleshooting “NO.18 COOLING SYSTEM CONCERNS-RUNS COLD”. (See NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [MZR 1.8, MZR 2.0, MZR 2.5].)
2	Perform the PCM DTC inspection using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.8, MZR 2.0, MZR 2.5].) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZR 1.8, MZR 2.0, MZR 2.5].)
No	Go to the next step.
3	Access the following PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZR 1.8, MZR 2.0, MZR 2.5].) • AC_REQ • COLP • CPP (MTX) • CPP/PNP (MTX) • TR (ATX) Are the PID values normal? (See PCM INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)	Yes	Go to the next step.
No	AC_REQ PID is not specified: • Inspect the refrigerant pressure switch and evaporator temperature sensor fan switch. (See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].) (See EVAPORATOR TEMPERATURE SENSOR INSPECTION [FULL-AUTO AIR CONDITIONER].) (See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER].) (See EVAPORATOR TEMPERATURE SENSOR INSPECTION [MANUAL AIR CONDITIONER].) COLP PID is not specified: • Inspect the refrigerant pressure switch (middle pressure). (See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].) (See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER].) CPP PID is not specified: (MTX) • Inspect the CPP switch. (See CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].) CPP/PNP PID is not specified: (MTX) • Inspect the neutral switch. (See NEUTRAL SWITCH INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].) TR PID is not specified: (ATX) • Inspect the TR switch. (See TRANSAXLE RANGE (TR) SWITCH INSTALLATION [FS5A-EL].) • Inspect communication error between TCM and PCM. Repair or replace the malfunctioning part according to the inspection results.
4	Is there air leakage felt or heard at the intake air system components while racing the engine to higher speed?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Inspect the following: • Electronic throttle control system operation (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].) • APP sensor (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].) Repair or replace the malfunctioning part according to the inspection results.
5	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 1.8, MZR 2.0, MZR 2.5].) • If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis. ― If the vehicle is repaired, troubleshooting is completed. ― If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP

INSPECTION

RESULTS

ACTION

Access the ECT PID using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZR 1.8, MZR 2.0, MZR 2.5].)

Start and warm up the engine to normal operating temperature.

Is the ECT PID value between 82—112 °C {180—234 °F}?

Yes

Go to the next step.

ECT PID value is higher than 112 °C {234 °F}:

• Go to the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”.

(See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR 1.8, MZR 2.0, MZR 2.5].)

ECT PID value is less than 82 °C {180 °F}:

• Go to the symptom troubleshooting “NO.18 COOLING SYSTEM CONCERNS-RUNS COLD”.

(See NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [MZR 1.8, MZR 2.0, MZR 2.5].)

Perform the PCM DTC inspection using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZR 1.8, MZR 2.0, MZR 2.5].)

Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [MZR 1.8, MZR 2.0, MZR 2.5].)

Go to the next step.

Access the following PIDs using the M-MDS:

(See ON-BOARD DIAGNOSTIC TEST [MZR 1.8, MZR 2.0, MZR 2.5].)

• AC_REQ

• COLP

• CPP (MTX)

• CPP/PNP (MTX)

• TR (ATX)

Are the PID values normal?

(See PCM INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)

Yes

Go to the next step.

AC_REQ PID is not specified:

• Inspect the refrigerant pressure switch and evaporator temperature sensor fan switch.

(See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)

(See EVAPORATOR TEMPERATURE SENSOR INSPECTION [FULL-AUTO AIR CONDITIONER].)

(See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER].)

(See EVAPORATOR TEMPERATURE SENSOR INSPECTION [MANUAL AIR CONDITIONER].)

COLP PID is not specified:

• Inspect the refrigerant pressure switch (middle pressure).

(See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)

(See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER].)

CPP PID is not specified: (MTX)

• Inspect the CPP switch.

(See CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)

CPP/PNP PID is not specified: (MTX)

• Inspect the neutral switch.

(See NEUTRAL SWITCH INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)

TR PID is not specified: (ATX)

• Inspect the TR switch.

(See TRANSAXLE RANGE (TR) SWITCH INSTALLATION [FS5A-EL].)

• Inspect communication error between TCM and PCM.

Repair or replace the malfunctioning part according to the inspection results.

Is there air leakage felt or heard at the intake air system components while racing the engine to higher speed?

Yes

Repair or replace the malfunctioning part according to the inspection results.

Inspect the following:

• Electronic throttle control system operation

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)

• APP sensor

(See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].)

Repair or replace the malfunctioning part according to the inspection results.

Verify test results.

• If normal, return to the diagnostic index to service any additional symptoms.

(See SYMPTOM DIAGNOSTIC INDEX [MZR 1.8, MZR 2.0, MZR 2.5].)

• If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis.

― If the vehicle is repaired, troubleshooting is completed.

― If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.