LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mazda >> 2017 >> CX-5 Grand Select, AWD >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic - Engine Control System (1 Of 5) >> DTC P0171-00: Fuel Trim System Too Lean >> Function Inspection Using M-MDS
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Function Inspection Using M-MDS

STEP INSPECTION RESULTS ACTION
1 PURPOSE: VERIFY RELATED REPAIR INFORMATION AVAILABILITY
  • 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.
2 PURPOSE: IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA
  • Is the DTC P0171:00 on FREEZE FRAME DATA?
 Yes Go to the next step.
No Go to the troubleshooting procedure for DTC on FREEZE FRAME DATA.
(See DTC TABLE [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .)
3 PURPOSE: RECORD VEHICLE STATUS AT TIME OF DTC DETECTION TO UTILIZE WITH REPEATABILITY VERIFICATION
NOTE:
  • Recording can be facilitated using the screen capture function of the PC.
  • Record the FREEZE FRAME DATA/snapshot data on the repair order.
 - Go to the next step.
4 PURPOSE: VERIFY IF INPUT SIGNAL TO PCM AFFECTS FUEL INJECTION Yes Inspect the suspected sensor and related wiring harness.
  • If there is any malfunction:
    • Repair or replace the malfunctioning part.
      • Go to the troubleshooting procedure to perform the procedure from Step 20.
  • If there is no malfunction:
    • Go to the next step.
No Go to the next step.
5 PURPOSE: VERIFY CONNECTOR CONNECTIONS
  • Start the engine.
  • Access the following PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .)
    • FUEL_PRES
    • FP
    • EVAPCP
    • MAF
    • MAP
    • MAP_V
    • IAT2
    • VT_EX_ACT
      • VT_IN_ACT
  • When the following parts are shaken, does the PID value include a PID item which has changed?
    • Fuel pressure sensor
    • Fuel pump control module
    • Purge solenoid valve
    • MAF sensor
    • MAP sensor/IAT sensor No. 2
    • OCV
    • Electric variable valve timing motor/driver
      • PCM
 Yes Repair or replace the applicable connector parts.
Go to the troubleshooting procedure to perform the procedure from Step 20.
No Go to the next step.
6 PURPOSE: VERIFY FUEL PRESSURE (HIGH-SIDE) MALFUNCTION Yes Go to the next step.
No FUEL_PRES PID value is lower than 3 MPa {31 kgf/cm2 , 435 psi}:
  • Go to the troubleshooting procedure to perform the procedure from Step 1. FUEL_PRES PID value is higher than 3 MPa {31 kgf/cm2 , 435 psi}:
  • Go to Step 8.
7 PURPOSE: VERIFY FUEL PRESSURE (LOW-SIDE) MALFUNCTION
NOTE:
  • Verify the fuel pressure on the low pressure side with the operation of the high pressure fuel pump turned off.
  • Bleed the remaining pressure in the fuel line using the following procedure.
    1. Switch the ignition off.
    2. Disconnect the high pressure fuel pump connector.
    3. Disconnect the fuel pump relay. (See RELAY LOCATION .)
    4. Start the engine and wait until the engine stalls.
  • Switch the ignition off.
  • Install the fuel pump relay.
  • Switch the ignition ON (engine off).
  • Display PID FUEL_PRES and simulation item FP using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .)
  • Turn simulation item FP on.
  • Is the FUEL_PRES PID value 405-485 kPa {4.13-4.94 kgf/cm2 , 58.8-70.3 psi}?
 Yes Go to the next step.
No Go to the troubleshooting procedure to perform the procedure from Step 5.
8 PURPOSE: VERIFY IF MALFUNCTION CAUSED BY FUEL INJECTOR IMPROPER OPERATION
  • Switch the ignition off.
  • Reconnect all disconnected connectors.
  • Start the engine and idle it.
  • Access the following simulation items using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .)
    • INJ_1
    • INJ_2
    • INJ_3
      • INJ_4
  • Turn each fuel injector from on to off using the simulation items.
  • Does the vibration during idling worsen?
 Yes Go to the next step.
No Go to the troubleshooting procedure to perform the procedure from Step 7.
9 PURPOSE: VERIFY IF MALFUNCTION CAUSED BY PURGE SOLENOID VALVE IMPROPER OPERATION Yes Go to the next step.
No Go to the troubleshooting procedure to perform the procedure from Step 8.
10 PURPOSE: VERIFY MAF SENSOR Yes Go to the next step.
No Go to the troubleshooting procedure to perform the procedure from Step 10.
11 PURPOSE: VERIFY MAP SENSOR Yes Go to the next step.
No Go to the troubleshooting procedure to perform the procedure from Step 12.
12 PURPOSE: VERIFY INTAKE VALVE TIMING Yes Go to the next step.
No Go to the troubleshooting procedure to perform the procedure from Step 14.
13 PURPOSE: VERIFY EXHAUST VALVE TIMING Yes Go to the next step.
No Go to the troubleshooting procedure to perform the procedure from Step 17.
14 PURPOSE: VERIFY A/F SENSOR Yes Go to the next step.
No Go to the troubleshooting procedure to perform the procedure from Step 18.
15 PURPOSE: VERIFY DTC Yes Go to the applicable DTC inspection.
(See DTC TABLE [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .)
Go to the troubleshooting procedure to perform the procedure from Step 1.
No Go to the troubleshooting procedure to perform the procedure from Step 1.
scientia non olet · About LEMON Manuals