Home

< Previous   Next >

2008 - MX-5 - Engine

NO.10 LOW IDLE/STALLS DURING DECELERATION [LF]



10

LOW IDLE/STALLS DURING DECELERATION

DESCRIPTION

  • Engine stops unexpectedly at the beginning of deceleration or recovery from deceleration.

POSSIBLE CAUSE

  • Vacuum leakage

  • Improper operation of electronic throttle control system

  • Air leakage from intake-air system

  • Improper air/fuel mixture ratio control

  • Evaporative emission control system malfunction

  • Accelerator pedal position sensor or related circuit malfunction

  • Accelerator pedal position sensor misadjustment

  • TP sensor or related circuit malfunction

  • MAF sensor or related circuit malfunction

  • Brake switch or related circuit malfunction

  • Neutral/clutch pedal position switch or related circuit malfunction (MT)

  • TR switch or related circuit malfunction (AT)

  • Improper A/C magnetic clutch operation


Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1

Does the engine idle roughly?

Yes

Go to symptom troubleshooting "No.8 Engine runs rough/rolling idle".

(See NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [LF].)

No

Go to the next step.

2

Turn off the A/C switch and fan switch.

Does the A/C magnetic clutch engage?

Yes

Go to symptom troubleshooting “No.24 A/C is always on or A/C compressor runs continuously.“

(See NO.24 A/C IS ALWAYS ON/A/C COMPRESSOR RUNS CONTINUOUSLY [LF].)

No

Go to the next step.

3

Verify the following:

  • Proper routing of and no damage to vacuum lines

  • No air leakage from intake-air system

Are all items normal?

Yes

Go to the next step.

No

Service if necessary.

Repeat Step 3.

4

Connect the M-MDS to the DLC-2.

Turn the ignition switch to the ON position (Engine off).

Retrieve any DTCs.

Are there any DTCs displayed?

Yes

DTC is displayed:

Go to the appropriate DTC inspection.

(See DTC TABLE [LF].)

No

No DTC is displayed:

Go to the next step.

5

Perform the electronic throttle control system operation inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF].)

Does the electronic throttle control system function properly?

Yes

Go to the next step.

No

Repair or replace the malfunctioning part according to electronic throttle control system operation inspection results.

6

Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side.

Plug opening end of vacuum hose.

Drive the vehicle.

Does the engine condition improve?

Yes

Inspect the evaporative emission control system.

No

Go to the next step.

7

Connect the M-MDS to the DLC-2.

Access APP1, APP2, TP, MAF and VSS PIDs.

Monitor each PID while driving vehicle.

(See PCM INSPECTION [LF].)

Are PIDs normal?

Yes

Go to the next step.

No

APP1, APP2 PIDs: Inspect the accelerator pedal position sensor.

TP PID: Inspect TP sensor.

MAF PID: Inspect MAF sensor.

VSS PID: Inspect VSS.

8

Access and monitor BOO, CPP (MT), CPP/PNP (MT), and TR (AT) PIDs.

Are PIDs values normal?

(See PCM INSPECTION [LF].)

Yes

Go to the next step.

No

If the BOO PID is not normal:

  • Inspect brake switch, and related wiring harness for vibration or intermittent open/short circuit.

If the CPP PID is not normal:

  • Inspect clutch position switch and related wiring harness for vibration or intermittent open/short circuit.

If the CPP/PNP PID is not normal:

  • Inspect neutral position switch and related wiring harness for vibration or intermittent open/short circuit.

If the TR PID is not normal:

  • Inspect TR switch and related wiring harness for vibration or intermittent open/short circuit.

9

  • Verify test results.

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

      (See SYMPTOM DIAGNOSTIC INDEX [LF].)

    • If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis.

      • If vehicle is repaired, troubleshooting completed.

      • If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.

        (See PCM INSPECTION [LF].)




< Previous   Next >
Back to Top
© 2012 Mazda North American Operations, U.S.A.