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Home >> Volvo >> 1992 >> 240 GL, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Self-Diagnostics - Turbo System >> Control Function No. 3 >> Testing Turbo System Components
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Testing Turbo System Components

  1. Turn ignition on. Locate diagnostic unit, and remove its cover. Connect selector cable to socket No. 5. Depress push button 3 times. Each time button is depressed, hold it for more than one second and less than 3 seconds.
  2. While LED flashes, cooling fan, turbo control valve and A/C blocking relay should operate. Check by listening or feeling component when it is activated. If turbo control valve does not work, go to step 3). If A/C blocking relay does not work, go to step 4). If cooling fan does not operate, check both cooling fan relays. Connect voltmeter between turbo control unit terminal No. 4 and ground and then between terminal No. 5 and ground. In both cases, reading should be 12 volts.
  3. Connect ohmmeter between turbo control unit terminals No. 1and 3. Reading should be 11 ohms. Replace control valve as necessary.
  4. Turn ignition on. Connect voltmeter between turbo control unit terminal No. 6 and ground. Reading should be 12 volts. Turn ignition off. Install turbo connector. Start engine, and turn A/C on.
  5. After compressor engages, press accelerator pedal to floor for a short time. Compressor should disengage when throttle is fully open and engage again when throttle closes slightly from fully open position. Replace A/C blocking relay as necessary. Turn ignition off.
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