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Symptom Troubleshooting - Engine Control System (Aj): NVH Mazda 6 GH

Testing & Diagnostics 2 illustrations ~261 words

Vibration Method

  1. If malfunction occurs or becomes worse while driving on a rough road or when engine is vibrating, perform the steps below. NOTE: There are several reasons vehicle or engine vibration could cause an electrical malfunction. Some of the things to check for are: Connectors not fully seated. Wire harnesses not having full play. Wires laying across brackets or moving parts. Wires routed too close to hot parts. An improperly routed, improperly clamped, or loose harness can cause wiring to become pinched between parts. The connector joints, points of vibration, and places such as where wire harnesses pass through the firewall, body panels are the major areas to be checked.

Scheme 149

Scheme 149: Inspection Method for Switch Connectors or Wires
  1. Connect the M-MDS to the DLC-2.
  2. Turn ignition switch to ON position (Engine OFF). NOTE: If the engine starts and runs, perform the following steps at idle.
  3. Access PIDs for the switch you are inspecting.
  4. Turn switch on manually.
  5. Shake each connector or wire harness a little vertically and horizontally while monitoring the PID. If PID value is unstable, check for poor connection.

Scheme 150

Scheme 150: Inspection Method for Sensor Connectors or Wires
  1. Connect the M-MDS to the DLC-2.
  2. Turn ignition switch to ON position (Engine OFF). NOTE: If engine starts and runs, perform the following steps at idle.
  3. Access PIDs for the switch you are inspecting.
  4. Shake each connector or wire harness a little vertically and horizontally while monitoring the PID. If PID value is unstable, check for poor connection.

NO. 21 ENGINE NOISE [AJ]

21Engine noise
DESCRIPTIONEngine noise from under hood
POSSIBLE CAUSESqueal, click or chirp noise: Improper engine oil level Improper drive belt tension Rattle sound noise: Loose parts Hiss sound noise: Vacuum leakage Loose spark plug Air leakage from intake-air system Improper VAD control system operation Rumble or grind noise: Improper drive belt tension Rap or roar sound noise: Exhaust system looseness Other noise: Camshaft friction gear noise or HLA noise Timing chain noise

POSSIBLE CAUSES DESCRIPTIONS

NO. 22 VIBRATION CONCERNS (ENGINE) [AJ]

22Vibration concerns (engine)
DESCRIPTIONVibration from under hood or driveline
POSSIBLE CAUSELoose attaching bolts or worn parts Components malfunction such as worn parts

POSSIBLE CAUSES DESCRIPTIONS