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Home >> Buick >> 2007 >> Lucerne CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 231 (Engine Controls - 3.9L - DTC P0442 To P2A01) >> DTC P1516, P2101, P2119 or P2176 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.
  1. Inspect the throttle body for the following conditions:
    • A throttle blade that is NOT in the rest position
    • A throttle blade that is binding open or closed
    • A throttle blade that is free to move open or closed WITHOUT spring pressure
  2. With the ignition ON and the throttle body disconnected, measure for voltage between the TAC motor control 1 and 2 circuits and a good ground. The voltage should be 0 volts.
    • If voltage is more than 0 volts, test the affected motor control circuit for a short to voltage or a faulty ECM.
  3. With the ignition ON and the throttle body disconnected, probe the TAC motor control 1 and 2 circuits with a test lamp connected to B+. The test lamp should not illuminate.
    • If test lamp illuminates, test the affected motor control circuit for a short to ground.
  4. Turn OFF the ignition.
  5. Connect a DMM between the TAC motor control 1 circuit and ground.
  6. Using the 1 ms Peak Min/Max feature, set to the 40 V scale, measure the voltage while turning ON the ignition. The max voltage should be within 0.5 volts of the B+.
    • If the voltage is not within 0.5 volt of B+, test the TAC motor control 1 circuit for an open, high resistance or for a faulty ECM.
  7. Turn OFF the ignition.
  8. Connect a DMM between the TAC motor control 2 circuit and ground.
  9. Using the 1 ms Peak Min/Max feature, set to the 40 V scale, measure the voltage while turning ON the ignition. The max voltage should be within 0.5 volts of the B+.
    • If the voltage is not within 0.5 volt of B+, test the TAC motor control 2 circuit for an open, high resistance or for a faulty ECM.
  10. If all circuits test normal, replace the throttle body.
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