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Engine Controls - Tests W/o Codes: Other Mercedes-Benz S-class W140 facelift

Testing & Diagnostics

ENGINE WILL NOT START

  1. Idle speed air valve.
  2. Differential pressure regulator (if equipped).
  3. Power and ground circuits.

Intermittent Simulation

To reproduce the conditions creating an intermittent fault, use the following methods

  1. Lightly tap on or vibrate suspect component.
  2. Heat suspect component.
  3. Wiggle or bend wiring harness.
  4. Spray suspect component with water.
  5. Remove/apply vacuum source.

Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for self-diagnostic codes. Use test results to identify a faulty component or circuit.

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