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HOMESERVICE MANUALSMAZDA20086 S SPORT, 4D HATCHBACK, STANDARDREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSISON-BOARD DIAGNOSTIC [ENGINE CONTROL SYSTEM (AJ]DTC P2178, P2180 [AJ]DIAGNOSTIC PROCEDURE
2008 Mazda 6 s Sport, 4D Hatchback, Standard

Diagnostic procedure

2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION Diagnostic procedure
DTC P2178, P2180 [AJ] DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED 
  • Have FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS (Fuel system related) been recorded?
 Yes Go to the next step.
No Record FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS on repair order, then go to the next step.
2 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.
3 VERIFY RELATED PENDING CODE OR STORED DTCs 
  • Turn ignition switch to OFF, then ON (Engine off).
  • Verify related pending code or stored DTCs using the M-MDS.
  • Is other DTC present?
 Yes If misfire DTC is present, go to Step 8.
If other DTC is present, go to the appropriate DTC troubleshooting procedure.
(See DTC TABLE [AJ] ).
No If driveability concern is present, go to Step 8.
If not, go to the next step.
4 IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA 
  • Is DTC P2178 or P2180 on FREEZE FRAME DATA?
 Yes Go to the next step.
No Go to troubleshooting procedures for DTC on FREEZE FRAME DATA.
5 VERIFY CURRENT INPUT SIGNAL STATUS (KEY TO ON/IDLE) 
  • Access APP1, APP2, ECT, MAF, TP and VSS PIDs using the M-MDS.
  • Is there any signal that is far out of specification when ignition switch is ON and engine runs?
 Yes Inspect suspected sensor and excessive resistance in related wiring harnesses.
Repair or if necessary.
Then go to Step 15.
No Go to the next step.
6 VERIFY CURRENT INPUT SIGNAL STATUS UNDER TROUBLE CONDITION 
  • Inspect same PIDs as Step 5 while simulating FREEZE FRAME DATA condition.
  • Is there any signal which causes drastic changes?
 Yes Inspect suspected sensor and related wiring harnesses repair or replace it.
Then go to Step 15.
No Go to the next step.
7 VERIFY CURRENT INPUT SIGNAL STATUS OF FRONT HO2S 
  • Start the engine and warm it up completely.
  • Access O2S11 (with P2178) or O2S21 (with P2180) PID using the M-MDS.
  • Check PID under following accelerator pedal condition (in PARK (ATX) or NEUTRAL (MTX)).
  • Is PID reading normal?
    • More than 0.45 V  when accelerator pedal is suddenly depressed (rich condition).
    • Less than 0.45 V  just after release of accelerator pedal (lean condition).
 Yes Go to the next step.
No Visually inspect for any gas leakage between exhaust manifold and front HO2S.

Then go to Step 15.
8 VERIFY CURRENT INPUT SIGNAL STATUS OF MAF SENSOR 
  • Start the engine.
  • Access the MAF PID using the M-MDS.
  • Verify that the MAF PID changes quickly according to engine speed.
  • Is the PID normal?
 Yes Go to the next step.
No Replace MAF/IAT sensor, then go to Step 15.
9 INSPECT PURGE SOLENOID OPERATION 
 Yes Go to the next step.
No Repair or replace malfunctioning part according to inspection result, then go to Step 15.
10 INSPECT PCV VALVE OPERATION 
 Yes Go to the next step.
No Replace PCV valve, then go to Step 15.
11 INSPECT EGR VALVE OPERATION 
 Yes Go to the next step.
No Repair or replace malfunctioning part according to inspection result, then go to Step 15.
12 INSPECT FUEL LINE PRESSURE 
 Yes If fuel pressure is too high, replace fuel pump unit, then go to Step 15.
If fuel line pressure is low, go to the next step.
No Go to Step 14.
13 INSPECT FUEL LEAKAGE FROM FUEL PUMP TO FUEL DELIVERY PIPE 
  • Visually inspect fuel line for any leakage.
  • Is any fuel leakage found?
 Yes Replace suspected fuel line, then go to Step 16.
No Inspect for foreign materials or stain inside fuel filter (low-pressure).
If for foreign materials or stain inside fuel filter (low-pressure), clean of fuel tank and filter.
Then go to Step 15.
14 INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION 
 Yes Go to the next step.
No Repair or replace malfunctioning part according to inspection results, then go to the next step.
15 VERIFY TROUBLESHOOTING OF DTC P2178 AND P2180 COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Clear DTC from PCM memory using M-MDS.
  • Perform the KOER SELF TEST using the M-MDS.

    (See KOEO/KOER SELF TEST [AJ] ).

  • Is the PENDING CODE same DTC present?
 Yes Replace PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [AJ] ).
No Go to the next step.
16 VERIFY AFTER REPAIR PROCEDURE 
 Yes Go to the applicable DTC inspection.
(See DTC TABLE [AJ] ).
No Troubleshooting completed.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.