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Home >> Mazda >> 2021 >> CX-3 FWD >> Repair and Diagnosis >> Engine Performance >> System >> Symptom Troubleshooting - Engine >> No. 12 Lack/Loss Of Power-Acceleration/Cruise >> Diagnostic Procedure

Diagnostic Procedure

NO. 12 LACK/LOSS OF POWER-ACCELERATION/CRUISE DIAGNOSTIC PROCEDURE

STEP INSPECTION RESULTS ACTION
1 VERIFY IF MALFUNCTION INCLUDES ROUGH IDLING
  • Does the engine idle rough?
 Yes Perform the symptom troubleshooting "NO. 8 ENGINE RUNS ROUGH/ROLLING IDLE".
(See NO. 8 ENGINE RUNS ROUGH/ROLLING IDLE .)
No Go to the next step.
2 VERIFY IF MALFUNCTION CAUSE IS OVERHEATING
  • Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .)
    CAUTION:
    • 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.
  • Is the ECT PID value less than 116°C {241°F} during driving?
 Yes Go to the next step.
No Perform the symptom troubleshooting "NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING".
(See NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING .)
3 CONFIRM DRIVE-BY-WIRE CONTROL SYSTEM OPERATES WITH BRAKE OVERRIDE SYSTEM
 Yes Go to the applicable DTC inspection. (drive-by-wire control system operates with brake override system.)
(See DTC P2299:00 .)
No Go to the next step.
4 VERIFY PCM DTC
 Yes Go to the applicable DTC inspection.
(See DTC TABLE .)
No Go to the next step.
5 VERIFY CURRENT INPUT SIGNAL STATUS
CAUTION:
  • 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 following PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST .)
    • APP1
    • APP2
    • CPP/PNP (MTX)
    • ECT
    • FUEL_PRES
    • IAT
    • MAF
    • MAP
    • MAP_V
    • TP_REL
    • O2S11
    • O2S12
    • SHRTFT1
      • LONGFT1
  • Do the PIDs indicate the correct values under the trouble condition? (See PCM INSPECTION .)
 Yes Go to the next step.
No APP1, APP2 PIDs are not as specified:

ECT PID is not as specified:

FUEL_PRES PID is not as specified:

IAT PID is not as specified:

MAF PID is not as specified:

MAP, MAP_V PIDs are not as specified:

TP_REL PID is not as specified:

O2S11, SHRTFT1, LONGFT1 PIDs are not as specified:

O2S12 PID is not as specified:

Repair or replace the malfunctioning part according to the inspection results.
  • If the malfunction remains:
    • Inspect communication error between TCM and PCM. (ATX)
      • Repair or replace the malfunctioning part according to the inspection results if necessary.
6 INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION
 Yes Go to the next step.
No Repair or replace the malfunctioning part according to the inspection results.
7 INSPECT FUEL INJECTOR OPERATION
 Yes Go to the next step.
No Repair or replace the malfunctioning part according to the inspection results.
8 INSPECT PURGE CONTROL SYSTEM OPERATION
 Yes Go to the next step.
No Repair or replace the malfunctioning part according to the inspection results.
9 INSPECT FUEL SYSTEM FOR FUEL LEAKAGE
  • Inspect for fuel leakage in the fuel line.
  • Is there any leakage?
 Yes Repair or replace the malfunctioning part according to the inspection results.
No Go to the next step.
10 INSPECT RELATED PART CONDITION
  • Inspect the following:
    • Fuel quality (proper octane, contamination, winter/summer blend)
    • Air leakage or restriction in intake-air system
    • Vacuum leakage
    • Air cleaner restricted or dirty
    • Clutch slippage (MTX)
    • Brake dragging
    • Tire air pressure
    • CKP sensor and intake CMP sensor
 Yes Service if necessary.
  • Repeat this step.
No Go to the next step.
11 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 ON-BOARD DIAGNOSTIC TEST .)
  • Is the FUEL_PRES PID value approx. 3 MPa {31 kgf/cm2 , 435 psi} (Without coolant control valve)/approx. 10 MPa {102 kgf/cm2 , 1450 psi} (With coolant control valve)?
 Yes Go to Step 13.
No Lower than approx. 3 MPa {31 kgf/cm2 , 435 psi} (Without coolant control valve)/approx. 10 MPa {102 kgf/cm2 , 1450 psi} (With coolant control valve):
  • If there is any malfunction:
    • Repair or replace the malfunctioning part according to the inspection results.
  • If there is no malfunction:
    • Go to the next step. Higher than approx. 3 MPa {31 kgf/cm2 , 435 psi} (Without coolant control valve)/approx. 10 MPa {102 kgf/cm2 , 1450 psi} (With coolant control valve):
  • Go to the next step.
12 INSPECT SPILL VALVE CONTROL SOLENOID VALVE CONTROL CIRCUIT FOR SHORT TO GROUND
  • Switch the ignition off.
  • Disconnect the high pressure fuel pump and PCM connectors.
  • Inspect for continuity between high pressure fuel pump terminal A (wiring harness-side) and body ground.
  • Is there continuity?
 Yes Refer to the wiring diagram and verify whether or not there is a common connector between high pressure fuel pump terminal A and PCM terminal 1EE (Without coolant control valve)/1DI (With coolant control valve).
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
  • Repair or replace the malfunctioning part.

If there is no common connector:
  • Repair or replace the wiring harness which has a short to ground.

If the malfunction remains:
No Replace the high pressure fuel pump.
(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION .)
13 INSPECT FUEL PRESSURE (LOW-SIDE)
  • Connect the fuel pressure gauge between fuel pump and high pressure fuel pump.
  • Measure the low side fuel pressure. (See FUEL LINE PRESSURE INSPECTION .)
  • Is the low side fuel pressure within specification?

Specification:
  • 425-505 kPa {4.34-5.14 kgf/cm2 , 61.7-73.2 psi}
 Yes Go to the next step.
No Inspect the following:
  • Fuel line restriction
  • Fuel filter clogged
    • If there is any malfunction:
      • Repair or replace the malfunctioning part according to the inspection results.
  • If there is no malfunction:
14 INSPECT THROTTLE BODY FOR CLOGGING
 Yes Clean the throttle valve.
No Go to the next step.
15 INSPECT ENGINE COMPRESSION
  • Measure the compression pressure for each cylinder. (See COMPRESSION INSPECTION .)
  • Are compression pressures within specification?
 Yes Go to Step 21.
No Go to the next step.
16 INSPECT ELECTRIC VARIABLE VALVE TIMING DRIVER
 Yes Replace the electric variable valve timing motor/driver.
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION .)
No Go to the next step.
17 INSPECT ELECTRIC VARIABLE VALVE TIMING MOTOR
 Yes Replace the electric variable valve timing motor/driver.
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION .)
No Go to the next step.
18 INSPECT ELECTRIC VARIABLE VALVE TIMING ACTUATOR
 Yes Replace the electric variable valve timing actuator.
(See ELECTRIC VARIABLE VALVE TIMING ACTUATOR, HYDRAULIC VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION .)
No Go to the next step.
19 INSPECT HYDRAULIC VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION
 Yes Repair or replace the malfunctioning part according to the inspection results.
No Go to the next step.
20 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 part according to the inspection results.
No Adjust the valve timing to the correct timing.
21 VERIFY SPARK PLUG CONDITION
  • Inspect the spark plug condition. (See SPARK PLUG INSPECTION .)
  • Is the spark plug wet, covered with carbon or grayish white?
 Yes Spark plug is wet or covered with carbon:

Spark plug is grayish white:
  • Inspect the fuel injector for restriction.
    • Repair or replace the malfunctioning part according to the inspection results.
No Go to the next step.
22 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 part according to the inspection results.
No Go to the next step.
23 INSPECT IF MALFUNCTION CAUSE IS PCV VALVE OR INJECTOR DRIVER (PCM INTEGRATED)
 Yes Replace the PCV valve.
(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION .)
No Injector driver malfunction.

If the problem remains, overhaul the engine.
24 Verify the test results.
  • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX .)
  • If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform 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.
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