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Home >> Volvo >> 1995 >> 850 GLT, 4D Sedan, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 2 (Engine Controls - Tests W/Codes - Non-Turbo (A/T) - MOTRONIC 4.4) >> Circuit Tests >> DTC 445 - Pulsed Secondary Air Injection System (Pair) Pump Signal >> 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, SIGNAL TOO HIGH, go to next step. If status message is PERMANENT FAULT, SIGNAL TOO LOW, go step  3. If status message is INTERMITTENT FAULT, SIGNAL TOO HIGH, go to step  7). If status message is INTERMITTENT FAULT, SIGNAL TOO LOW, go to step  8.
  2. Turn ignition off. Disconnect PAIR pump relay connector "B". See Figure. Turn ignition on. Connect test light between relay connector "B" terminal No. 1 and ground. If test light does not come on, replace PAIR pump relay. If test light comes on, check wire between PAIR pump relay connector "B" terminal No. 1 and ECM connector terminal B38 for short circuit to supply voltage. Repair as necessary.
  3. If status message is PERMANENT FAULT, SIGNAL TOO LOW, turn ignition off. Disconnect PAIR pump relay connector "A". See Figure. Turn ignition on. Connect voltmeter between relay connector "A" and ground. If voltmeter reads battery voltage, go to next step. If battery voltage is not present, check for short circuit to ground in fusible link between battery and PAIR pump relay connector "A" terminal No. 1. Also check for open circuit in wiring between PAIR pump relay connector "A" terminal No. 1.
  4. Disconnect PAIR pump relay connector "B". Connect ohmmeter between relay connector "B" terminal No. 1 and ground. If ohmmeter reads infinite resistance, go to next step. If ohmmeter does not read infinite resistance, check for short circuit in wire between PAIR pump relay connector "B" terminal No. 1 and ECM connector terminal B38.
  5. Connect Breakout Box (981-3190) to ECM connector. Check all grounds. Disconnect PAIR pump relay connector "B". Connect ohmmeter between relay connector "B" terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check for an open circuit in wire between PAIR pump relay connector "B" terminal No. 1 and ECM connector terminal B38.
  6. Turn ignition off. Reconnect all wiring to PAIR pump relay. Turn ignition on. Using scan tool, activate PAIR pump. If PAIR pump does not start, replace PAIR pump relay. If PAIR pump does start, DTC is caused by poor contact in PAIR pump relay connectors. Repair as necessary.
  7. If status message is INTERMITTENT FAULT, SIGNAL TOO HIGH, check wiring between PAIR pump relay terminal B1 and ECM connector terminal B38 for an intermittent short to voltage. Repair as necessary.
  8. If status message is SIGNAL TOO LOW, INTERMITTENT FAULT, check PAIR pump relay and ECM connectors for poor terminal contact. Repair as necessary. Check wiring between PAIR pump relay terminal B1 and ECM connector terminal B38 for an intermittent open or short circuit to ground. Also check wiring between PAIR pump relay terminal A1 and battery voltage for an intermittent open circuit.
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