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Home >> Volvo >> 1995 >> 850 Base, 4D Sedan, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Turbo >> Diagnostic Trouble Code Testing >> MOTRONIC 4.3 Control System >> Code 4-1-4: Charge Pressure Control

Code 4-1-4: Charge Pressure Control

  1. Turn ignition on. Leave MAF sensor connected. Connect voltmeter between MAF sensor connector terminals No. 2 and 4. If voltmeter reads .1-.2 volt, go to step 3). If voltmeter does not read .1-.2 volt, go to next step.
  2. Turn ignition off. Ensure MAF sensor and ECM connector terminals are clean and tight. Repair as necessary. Reconnect connectors. Turn ignition on. Connect voltmeter between MAF sensor connector terminals No. 2 and 4. If voltmeter reads .1-.2 volt, source of code was poor contact in MAF or ECM connector terminals. If voltmeter does not read .1-.2 volt, retest using new MAF sensor.
  3. Turn ignition off. Connect breakout box and check grounds. See COMPUTERIZED ENGINE CONTROLS in SYSTEM/COMPONENT TESTS article. Disconnect ECM. Turn ignition on. Connect voltmeter between breakout box pin No. 42 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check wiring between ECM terminal B42 and Transmission Control Module (TCM) terminal B1 for an intermittent fault.
  4. Turn ignition off. Check Turbocharger (TC) control valve and ECM connector for contact resistance or poor contact. Repair as necessary. Reconnect TC control valve and ECM connectors. Turn ignition on. Using Volvo scan tool in Diagnostic Test Mode (DTM) No. 3, check that TC control valve ticks. If TC control valve ticks, go to next step. If TC control valve does not tick, retest using new TC control valve.
  5. Turn ignition off. Check hoses between TC and TC control valve, and hose between TC control valve and pressure servo for wastegate valve for obstruction or kinks. Also check that TC control valve is not blocked between Red and Yellow connectors when valve is activated. Valve should be open between Red and Yellow connectors when not activated. If hoses and TC control valve are okay, go to next step. If hoses and/or TC control valve are blocked, repair as necessary.
  6. Turn ignition off. Remove hose from pressure servo. Connect Manometer (999-5230 ) and Pressure Tester (998-5496 ) to pressure servo. Pump up pressure to about 46.6 psi. If pressure servo fully opens, check pressure servo setting. See procedures in the SYSTEM/COMPONENT TESTS article. Replace wastegate valve pressure servo. If pressure servo is not okay, retest with a new pressure servo. Replace wastegate valve pressure servo.
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