Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSMAZDA20086 S SPORT, 4D HATCHBACK, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 600 (SYMPTOM TROUBLESHOOTING [ENGINE CONTROL SYSTEM L3 WITH TC))ENGINE CONTROL SYSTEM OPERATION INSPECTIONEGR CONTROL SYSTEM INSPECTION
2008 Mazda 6 s Sport, 4D Hatchback, Standard
EGR Control System Inspection
2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION EGR Control System Inspection
WARNING: This page is about a different car, the 2007 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
If simulation function of M-MDS is used:Β
- Crank the engine and verify that the EGR valve operation (initial operation) sound is heard.
- If the operation sound is not heard, connect the M-MDS to the DLC-2 and verify that the DTC P0403 is shown. Perform the DTC inspection. (See DTC TABLE ).
- Start the engine run it is idling.
- Increase the step value of the EGR valve from 0 to 40Β using the SEGR PID of the simulation function.
- Operate the EGR valve and inspect if the engine speed becomes unstable or the engine stalls.
- If the engine speed does not change, proceed to the following.
- Stop the engine.
- Remove the EGR valve.
- Connect the EGR valve connector.
- Turn the ignition switch to the ON position.
- Increase the step value of EGR valve from 0 to 40 using SEGRP PID.
- Verify that the EGR valve operates according to the SEGRP PID.
- If the EGR valve is operated, clean the EGR valve and the EGR gas passage.
- If the EGR valve does not operate, replace the EGR valve.
- If the engine speed does not change, proceed to the following.
- Start the engine and warm it up completely.
- Access the following PIDs.
- ECT, RPM, SEGRP, APP1, APP2, TP_REL, VSS
- Idle the vehicle and verify that the SEGRP value is 0.Β
- Put the vehicle in drive.
- Depress the accelerator pedal and verify that the SEGRP value increases.
- If the SEGRP value does not increase, inspect the VSS, TP and ECT PIDs. (See PCM INSPECTION ).
- Stop the vehicle and verify that the SEGRP value is returns to 0.Β
If simulation function of M-MDS is not used:Β
- Verify that EGR valve operation (initial operation) sound is heard when the ignition switch is turned to the ON position.
- If the operation sound is not heard, connect the M-MDS to the DLC-2 and verify that the DTC P0403 is shown. Perform the DTC inspection. (See DTC TABLE ).
- Start the engine and idle it.
- Warm up the engine to normal operating temperature.
- Select the following PIDs:
- ECT, RPM, SEGRP, APP1, APP2, TP_REL, VSS
- Let the vehicle idle and verify that the SEGRP value is 0.
- Put the vehicle in drive.
- Depress the accelerator pedal and verify that the SEGRP value is increased.
- If the EGR valve increases, inspect the following:
- EGR valve (stuck open or closed)
- Wiring harness and connectors (Main relay - EGR valve - PCM)
- If the SEGRP value does not increase, inspect the VSS, APP1, APP2, TP_REL and ECT PIDs. (See PCM INSPECTION ).
- If the EGR valve increases, inspect the following:
- Stop the vehicle and verify that the SEGRP value returns to 0.Β
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.