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Home >> Mazda >> 2021 >> CX-30 Turbo Premium >> Repair and Diagnosis >> External Pages >> Different car >> Section 29 (Symptom Troubleshooting - Engine) >> Engine Stalls/Quits, Engine Runs Rough, Misses, Buck/Jerk, Hesitation/Stumble, Surges (Us) >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.
ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES (SKYACTIV-G, US) DIAGNOSTIC PROCEDURE

Step Inspection Results Action
1 VERIFY IF MALFUNCTION INCLUDES HARD ENGINE STARTING
  • Is the engine unable to start after it has stalled?
    NOTE:
    • If the ignition is not switched off or ACC after the engine stalls, and then an engine restart is attempted, the PCM corrects the difference between CKP sensor and CMP sensor signals caused by engine stalling, which may result in more time needed to restart the engine.
 Yes If the engine is unable to start, perform the symptom troubleshooting "WILL NOT CRANK" and "CRANKS NORMALLY BUT WILL NOT START".
(See WILL NOT CRANK (US) .)
(See CRANKS NORMALLY BUT WILL NOT START .)
No Go to the next step.
2 VERIFY IF MALFUNCTION INCLUDES ROUGH IDLING
  • Does the engine idle rough?
 Yes Perform the symptom troubleshooting "ENGINE RUNS ROUGH/ROLLING IDLE".
(See ENGINE RUNS ROUGH/ROLLING IDLE (US) .)
No Go to the next step.
3 VERIFY IF MALFUNCTION CAUSE IS OVERHEATING
WARNING:
  • While performing this step, always operate the vehicle in a safe and lawful manner.
  • When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later.
  • Access the ECT PID using the MMDS. (See PID/DATA MONITOR INSPECTION .)
  • Is the ECT PID value less than 116°C {241°F} during driving?
 Yes Go to the next step.
No The cause of this concern could be from the cooling system overheating.
4 CONFIRM DRIVE-BY-WIRE CONTROL SYSTEM OPERATES WITH BRAKE OVERRIDE SYSTEM
  • Perform the DTC inspection for the PCM. (See DTC INSPECTION .)
  • Is the DTC P2299:00 present?
 Yes Repair the malfunctioning location according to the applicable DTC troubleshooting. (Drive-by-wire control system operates with brake override system.)
(See DTC P2299:00 [PCM (SKYACTIV-G)] .)
No Go to the next step.
5 VERIFY PCM DTC
  • Perform the DTC inspection for the PCM. (See DTC INSPECTION .)
  • Are any DTCs displayed?
 Yes Repair the malfunctioning location according to the applicable DTC troubleshooting.
(See DTC TABLE [PCM (SKYACTIV-G (US))] .)
No Go to the next step.
6 VERIFY CURRENT INPUT SIGNAL STATUS
WARNING:
  • While performing this step, always operate the vehicle in a safe and lawful manner.
  • When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later.
 Yes Go to the next step.
No APP1, APP2 PIDs are not as specified:

CLTCH_PEDAL_POS PID is not as specified: (MTX)

ECT, ECT_VOLT, ECT2, ECT2_VOLT PIDs are not as specified:

FUEL_PRES PID is not as specified:

IAT PID is not as specified:

MAF PID is not as specified:

MAP, MAP_VOLT PIDs are not as specified:

A/F_SEN_CUR, SHRT_FUEL_TRIM, LONG_FUEL_TRIM PIDs are not as specified:

HO2S_OUT_VOLT PID is not as specified:

Repair or replace the malfunctioning location.
  • If the malfunction remains:
    • Inspect communication error between TCM and PCM. (ATX)
      • Repair or replace the malfunctioning location and perform the repair completion verification.
7 INSPECT A/C CUT-OFF CONTROL SYSTEM OPERATION
 Yes Go to the next step.
No Perform the symptom troubleshooting "A/C DOES NOT WORK SUFFICIENTLY" and "A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY".
(See A/C DOES NOT WORK SUFFICIENTLY .)
(See A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY .)
8 DETERMINE IF MALFUNCTION CAUSE IS DRIVE-BY-WIRE CONTROL SYSTEM OR OTHER
  • Will the engine run smoothly at part throttle?
 Yes Go to Step 10.
No Go to the next step.
9 INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION
 Yes Visually inspect the throttle body (damage/scratching).
  • If there is any malfunction:
    • Repair or replace the malfunctioning location and perform the repair completion verification.
  • If there is no malfunction:
    • Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
10 INSPECT FUEL INJECTOR OPERATION
 Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
11 INSPECT PURGE CONTROL SYSTEM OPERATION
 Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
12 INSPECT CURRENT A/F SENSOR SIGNAL
 Yes Go to the next step.
No Go to Step 14.
13 DETERMINE IF MALFUNCTION CAUSE IS A/F SENSOR MALFUNCTION OR A/F SENSOR RELATED WIRING HARNESS MALFUNCTION
NOTE:
  • If the inspection in Step 13 is performed, the PCM detects a DTC and performs fail-safe control. After performing the inspection, clear DTCs using the M-MDS.
  • Switch the ignition off.
  • Disconnect the A/F sensor connector.
  • Verify the symptom.
  • Does the symptom disappear?
 Yes Replace the A/F sensor and perform the repair completion verification.
(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G (VIN M (US))] .)
(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G (VIN L (US))] .)
No Inspect the following:
  • Exhaust system leakage between exhaust manifold and A/F sensor
  • Loose installation of A/F sensor
    • If there is any malfunction:
      • Repair or replace the malfunctioning location and perform the repair completion verification.
    • If there is no malfunction:
  • Inspect the A/F sensor signal circuit.
    • Repair or replace the suspected wiring harness if necessary and perform the repair completion verification.
14 INSPECT RELATED PART CONDITION
 Yes Repair or replace the malfunctioning location and perform the repair completion verification.
No Go to the next step.
15 INSPECT FUEL PRESSURE (HIGH-SIDE)
  • Start the engine and warm it up completely.
  • Access the FUEL_PRES PID using the M-MDS at idle. (See PID/DATA MONITOR INSPECTION .)
  • Is the FUEL_PRES PID value within specification?

Specification:
  • Approx. 10 MPa {102 kgf/cm2 , 1450 psi}
 Yes Go to Step 17.
No Lower than specification:

Higher than specification:
  • Go to the next step.
16 INSPECT SPILL VALVE CONTROL SOLENOID VALVE CONTROL CIRCUIT FOR SHORT TO GROUND
  • Inspect the applicable circuit for a short to ground. (See CIRCUIT INSPECTION .)
  • Is the circuit normal?
 Yes Replace the high pressure fuel pump and perform the repair completion verification.
(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [SKYACTIV-G (VIN M (US))] .)
(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [SKYACTIV-G (VIN L (US))] .)
No Repair or replace the malfunctioning location and perform the repair completion verification.
17 INSPECT FUEL PRESSURE (LOW-SIDE)

Specification:
  • 475-555 kPa {4.85-5.65 kgf/cm2 , 68.9-80.4 psi}
 Yes Go to the next step.
No Inspect the following:
18 INSPECT THROTTLE BODY FOR CLOGGING
 Yes Clean the throttle valve and perform the repair completion verification.
No Go to the next step.
19 INSPECT ENGINE COMPRESSION
 Yes Go to Step 25.
No Go to the next step.
20 INSPECT ELECTRIC VARIABLE VALVE TIMING DRIVER FOR MALFUNCTION
 Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G (VIN M (US))] .)
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G (VIN L (US))] .)
21 INSPECT ELECTRIC VARIABLE VALVE TIMING MOTOR FOR MALFUNCTION
 Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G (VIN M (US))] .)
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G (VIN L (US))] .)
22 INSPECT ELECTRIC VARIABLE VALVE TIMING ACTUATOR FOR MALFUNCTION
 Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
(See ELECTRIC VARIABLE VALVE TIMING ACTUATOR, HYDRAULIC VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION [SKYACTIV-G (VIN M (US))] .)
(See ELECTRIC VARIABLE VALVE TIMING ACTUATOR, HYDRAULIC VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION [SKYACTIV-G (VIN L (US))] .)
23 INSPECT HYDRAULIC VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION
 Yes Repair or replace the malfunctioning location and perform the repair completion verification.
No Go to the next step.
24 INSPECT FOR MALFUNCTION DUE TO DEVIATED VALVE TIMING
 Yes Inspect for the following engine internal parts:
  • Cylinder
  • Piston ring
  • Intake valve
  • Exhaust valve
  • Such as cylinder head gasket
    • If there is any malfunction:
      • Repair or replace the malfunctioning location and perform the repair completion verification.
No Adjust the valve timing to the correct timing and perform the repair completion verification.
25 INSPECT IGNITION SYSTEM OPERATION
 Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
26 INSPECT EXHAUST SYSTEM FOR RESTRICTION
  • Inspect for restriction in the exhaust system and the TWC.
  • Is there any restriction?
 Yes Repair or replace the malfunctioning location and perform the repair completion verification.
No Go to the next step.
27 INSPECT PCV VALVE FOR MALFUNCTION
 Yes Except U.S.A. And CANADA:
  • Go to the next step.

U.S.A. And CANADA:
No Repair or replace the malfunctioning location and perform the repair completion verification.
(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [SKYACTIV-G (VIN M (US))] .)
(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [SKYACTIV-G (VIN L (US))] .)
28 INSPECT IF MALFUNCTION CAUSE IS CHECK VALVE OR INJECTOR DRIVER (PCM INTEGRATED)
 Yes Replace the check valve and perform the repair completion verification.
(See CHECK VALVE REMOVAL/INSTALLATION [SKYACTIV-G (VIN M (US))] .)
(See CHECK VALVE REMOVAL/INSTALLATION [SKYACTIV-G (VIN L (US))] .)
No Injector driver malfunction.

If the problem remains, overhaul the engine and perform the repair completion verification.
Repair completion verification 1 VERIFY THAT VEHICLE IS REPAIRED
  • Install/connect the part removed/disconnected during the troubleshooting procedure.
  • Has the malfunction symptom been eliminated?
 Yes Complete the symptom troubleshooting. (Explain contents of repair to customer)
No Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error.
(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(US)] .)
  • If the CAN communication is normal, perform the diagnosis from Step 1.
    • If the malfunction recurs, go to the next step.
Repair completion verification 2 VERIFY IF MALFUNCTION IS CAUSED BY NOT PERFORMING PCM REPROGRAMMING
  • Verify repair information and verify that there is a new calibration in the PCM.
  • Is there a new calibration in the PCM?
 Yes Perform the PCM reprogramming and verify if the malfunction symptom was corrected.
No Replace the PCM. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G (VIN M (US))] .)
(See PCM REMOVAL/INSTALLATION [SKYACTIV-G (VIN L (US))] .)
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