Symptom Troubleshooting - Engine: Overview — Mazda MX-5 NC (2005-2008)

Symptom Troubleshooting - Engine: Overview Mazda MX-5 NC

Scheme 1: SYMPTOM TROUBLESHOOTING WIRING DIAGRAM [LF]

Main Relay Operation Inspection

Verify that the main relay clicks when the ignition switch is turned to ON position and off. If there is no operation sound, inspect the following: Main relay (See «RELAY INSPECTION».) Harness and connector between battery and main relay terminal A. Harness and connector between PCM terminal 1Q and main relay terminal E.

Start the engine.
Inspect the rod operation. (See «VARIABLE INTAKE AIR SHUTTER VALVE ACTUATOR INSPECTION [LF]».) If the rod operation is not as specified, inspect as follows: Stop the engine. Connect the WDS or equivalent to the DLC-2. Verify that DTC P0661 or P0662 is not displayed. If DTC P0661 or P0662 is shown, perform DTC inspection. (See «DTC TABLE [LF]»(/mazda/mx-5/nc-2005-2008/remont/testing-diagnostics/#on-board-diagnostic-engine-control-system).) Inspect the variable intake air solenoid valve. (See «VARIABLE INTAKE AIR SOLENOID VALVE INSPECTION [LF]».) If the variable intake air solenoid valve is not normal, replace the variable intake air solenoid valve. (See «INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [LF]».) If the variable intake air solenoid valve is normal, inspect the following: Vacuum hose and vacuum chamber for looseness or damage Shutter valve actuator (See «VARIABLE INTAKE AIR SHUTTER VALVE ACTUATOR INSPECTION [LF]».) Shutter valve stuck open or closed

Remove the fuel-filler cap.
Turn the ignition switch to the ON position.
Turn the fuel pump relay from off to on using the FP PID and inspect if the operation sound is heard. If no operation sounds is heard, proceed to next step.
Measure voltage at wiring harness side fuel pump connector terminal B. Specification B+ (Ignition switch at on) If the voltage is as specified, inspect the following: Fuel pump continuity Fuel pump GND Wiring harness between fuel pump relay and PCM terminal 1H If not as specified, inspect the following: Fuel pump relay Wiring harness connector (Main relay-fuel pump relay-fuel pump.)

The EVAP system test finds gas leaks in the system using the PCM to monitor changes in the air pump load current of the EVAP system leak detection pump. This test starts after sending an on-demand test signal from the WDS to the PCM. The PCM controls the air pump and change-over-valve operation and also stores the load current of the air pump as follows: The PCM commands turn the air pump on and retrieve the air pump load current value (LDP_MON PID) as a reference current (LDP_REF PID). After retrieving a reference current value, the PCM commands the change-over-valve to open, then captures the air pump load current value (LDP_MON PID) as idle current (LDP_IDL PID). The EVAP system will be pressurized from this phase. The PCM continues to monitor the air pump load current value (LDP_MON PID) until the end of the test.
You can confirm whether any evaporative gas leak occurred or not by reading the test results.