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Home >> Cadillac >> 2007 >> DTS 4.6 9 >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System & Fuel System - 4.6L - DTC P0351 To P2440 >> DTC P1682 >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition ON, observe the Ignition 1 Signal and EC Ignition Relay Feedback scan tool parameters to determine which is less than B+.
  2. Ignition OFF, remove the relay that corresponds to the scan tool parameter that is less than B+.
  3. IMPORTANT: Six ohms or greater in the circuit/underhood fuse block will cause the DTC to set.
  4. Ignition ON, connect a 3A fused jumper wire between B+ and the applicable ignition 1 circuit terminal. Verify that the applicable scan tool parameter displays B+.
    • If the applicable scan tool parameter is less than the specified value, test the ignition 1 circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  5. If all circuits test normal, test or replace the applicable relay.