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Home >> Volvo >> 1993 >> 850 Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Trouble Code Testing >> Ignition System Trouble Code Diagnosis >> 4-1-1 (Throttle Switch Signal Absent Or Faulty)

4-1-1 (Throttle Switch Signal Absent Or Faulty)

  1. Activate fuel injection diagnostic test mode No. 1. See DIAGNOSTIC TEST MODE NO. 1 under SELF-DIAGNOSTICS  . Check whether throttle switch code is recorded. If code is recorded, see 4-1-1 (THROTTLE SWITCH SIGNAL ABSENT OR FAULTY) under FUEL INJECTION SYSTEM TESTING. If fault is not in fuel injection system, connect measuring unit to ignition ECU. See MEASURING UNIT  under SELF-DIAGNOSTIC SYSTEM.
  2. Ensure ignition is off. Connect ohmmeter between measuring unit terminals No. 20 and 50. Very high or infinite resistance should be present. A reading of zero ohms indicates a short to ground is present.
  3. Connect voltmeter between measuring unit terminals No. 20 and 50. Turn ignition on. If battery voltage is present, circuit is shorted to voltage. If resistance and voltage measurements are okay but signal is still absent, turn ignition off.
  4. Use an ohmmeter and check continuity between ignition and fuel injection ECU terminals No. 20 (Green/Brown wire). If circuit is okay but signal is still not present, repeat test using a known good fuel injection ECU. Clear codes if any exist in other systems. Check diagnostic test mode No. 1 to check for codes in A/T and ignition system if code is displayed. See DIAGNOSTIC TEST MODE NO. 1 under SELF-DIAGNOSTICS  .
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