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Chart A-1, No Check Engine Light (Turbo): Notes

There should always be a steady CHECK ENGINE light when ignition is on and engine stopped. Battery voltage is supplied to bulb through C7 (10-amp) fuse. The Electronic Control Module (ECM) turns the light on by providing a ground path through Purple wire.

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. Battery voltage terminals B1 and C16 are protected by a fusible link, located in relay/fuse box under the hood, near the battery.
  2. If voltage is present at terminals B1 and C16, check for faulty ECM grounds or faulty ECM.
  3. Using a test light connected to 12 volts, probe each system ground circuits to ensure a good ground is present.
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