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Home >> Chevrolet >> 2015 >> Impala Limited LS >> Repair and Diagnosis >> Engine Performance >> System >> Data Communication System >> Diagnostic Information and Procedures >> DTC U1826 or U1827: Lost Communication Module >> Circuit/System Testing
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Circuit/System Testing

Yaw Rate Sensor DTC U1826

  1. Ignition OFF, disconnect the harness connector at the Yaw Rate Sensor.
  2. Test for less than 10 Ω between the Yaw Rate Sensor ground circuit terminal 6 and ground.
    • If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the Yaw Rate Sensor voltage (12 V reference) circuit terminal 1 and ground.
    • If the test lamp does not illuminate, test the circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the EBCM.
  4. Ignition OFF, disconnect the harness connector at the EBCM.
  5. Test for less than 2 Ω in each pair of serial data circuits between the Yaw Rate Sensor and the EBCM:
    • Yaw Rate Sensor serial data circuit terminal 2 and EBCM serial data circuit terminal 33
    • Yaw Rate Sensor serial data circuit terminal 3 and EBCM serial data circuit terminal 21
    • If greater than 2 Ω, test the Yaw Rate Sensor serial data circuits terminals 2 and 3 for an open/high resistance.
  6. If all circuits test normal, replace the Yaw Rate Sensor.

Steering Wheel Position Sensor (Steering Angle Sensor) DTC U1827

  1. Ignition OFF, disconnect the harness connector at the Steering Wheel Position Sensor.
  2. Test for less than 10 Ω between the Steering Wheel Position Sensor ground circuit terminal 1 and ground.
    • If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the Steering Wheel Position Sensor voltage (12 V reference) circuit terminal 2 and ground.
    • If the test lamp does not illuminate, test the circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the EBCM.
  4. Ignition OFF, disconnect the harness connector at the Yaw Rate Sensor.
  5. Test for less than 2 Ω in each pair of serial data circuits between the Steering Wheel Position Sensor and the Yaw Rate Sensor:
    • Steering Wheel Position Sensor serial data circuit terminal 3 and Yaw Rate Sensor serial data circuit terminal 4
    • Steering Wheel Position Sensor serial data circuit terminal 4 and Yaw Rate Sensor serial data circuit terminal 5
    • If greater than 2 Ω, test the Steering Wheel Position Sensor serial data circuits terminals 3 and 4 for an open/high resistance.
  6. If all circuits test normal, replace the Steering Wheel Position Sensor.
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