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Home >> Volvo >> 1995 >> 850 GLT, 4D Sedan, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 3 (Engine Controls - Tests W/Codes - Non-Turbo (M/T) - MOTRONIC 4.4) >> Circuit Tests >> DTC 446 - Pulsed Secondary Air Injection System (Pair) Pump Flow Fault >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 1996 Volvo 850. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check status message on scan tool. If status message is PERMANENT FAULT, go to next step. If status message is INTERMITTENT FAULT, check for air leakage in exhaust system. Also check PAIR pipe for damage and leakage.
  2. Turn ignition off. Carefully disconnect vacuum hose from solenoid valve. Connect vacuum gauge to solenoid valve. Start and idle engine so it reaches normal operating temperature. Start PAIR pump. If vacuum gauge indicates no vacuum, go to next step. If vacuum gauge indicates vacuum, turn ignition off. Disconnect solenoid valve connector. Connect vacuum gauge to solenoid valve. Start and idle engine so it reaches normal operating temperature. If vacuum gauge indicates no vacuum, check for a short circuit to ground in wiring between solenoid valve terminal No. 2 and ECM connector terminal A37. If vacuum gauge indicates vacuum, replace solenoid valve.
  3. Disconnect PAIR valve from pipe, leaving hoses in place. Turn ignition on. Using scan tool, activate PAIR pump. If no air escapes from PAIR valve outlet, check for air leakage in exhaust system. Repair as necessary. If air does escape from PAIR valve outlet, replace PAIR valve.
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