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Home >> Cadillac >> 2007 >> DTS 4.6 9 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 4.6L - DTC P0016 To P0341 >> DTC P0340 or P0341 >> Circuit/System Testing

Circuit/System Testing

  1. With the ignition OFF, Inspect the engine wiring harnesses carrying the CMP sensor circuits for the following conditions:
    • Close routing of aftermarket electrical equipment
    • Close to solenoids, motors, and relays
    • Correct any wire harness routing or component placement conditions, if it is determined to be a possible source of electrical interference.
  2. Disconnect the cam sensor.
  3. With the ignition ON and the engine OFF, measure for 4.8-5.2 volts at the ECM side of the connector between the 5-volt reference circuit of the CMP sensor and a good ground.
    • If the voltage is less than 4.8 volts, test for an open in the 5-volt reference circuit. If the circuit tests normal, replace the control module.
  4. With the ignition ON and the engine OFF, measure for 4.8-5.2 volts at the ECM side of the connector between the CMP sensor signal circuit and a good ground.
    • If the voltage is less than 4.8 volts, test for an open or a short to ground in the CMP sensor signal circuit. If the circuit tests normal, replace the control module.
    • If the voltage is more than 5.2 volts, test for a short to voltage in the CMP sensor signal circuit. If the circuit tests normal, replace the control module.
  5. With the ignition ON and the engine OFF, measure for 1-3 mA, at the ECM side of the connector between the CMP sensor signal circuit and a good ground.
    • If the amperage is more than 3 mA, test the CMP sensor signal circuit for a short to the 5-volt reference circuit. If the circuit tests normal, replace the control module.
  6. Connect a fused jumper wire to a good ground.
  7. With the ignition ON and the engine OFF, observe the CMP Sensor parameter on the scan tool.
  8. Touch the jumper wire to the CMP sensor signal circuit repeatedly at the ECM side of the connector. The CMP Sensor parameter should display a value other than 0 RPM.
    • If the CMP Sensor parameter displays 0 RPM, replace the ECM.
  9. With the ignition ON and the engine OFF, measure for B+ at the ECM side of the connector between the low reference circuit of the CMP sensor and the battery positive post.
    • If the voltage measured between the low reference circuit and the battery positive post is not the same as voltage measured between a good ground and the battery positive post, test for an open/high resistance in the low reference circuit. If the circuit tests normal, replace the control module.
  10. With the ignition OFF, inspect the wiring harness to the CMP sensor, for any damage, opens, or shorts.
    • Repair any wiring or connector damage, if necessary.
  11. Inspect the CMP sensor for looseness. Remove the CMP sensor from the engine and inspect the sensor and the O-ring for damage.
    • Repair or replace the CMP sensor, if necessary.
  12. Reconnect the CMP sensor to the harness.
  13. Turn ON the ignition, with the engine OFF.
  14. While observing the CMP Sensor and CMP Active Counter parameters on the scan tool, pass a steel object by the tip of the sensor repeatedly. The CMP Active Counter parameter should increment and the CMP Sensor parameter should display a value other than 0 RPM.
    • If the parameters remain at 0, replace the CMP sensor.
  15. Inspect the reluctor wheel for damage.
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