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DTC P1458: A/C Compressor Control

  1. Disconnect A/C-heater control unit and ECM connector. Connect ohmmeter between ECM connector terminal No. 11 (Blue wire) and A/C-heater control unit connector terminal K23 (Green/Blue wire). If continuity is present, go to next step. If continuity is not present, check Blue and Green/Blue wires, and in-line connectors for an open circuit.
  2. Disconnect A/C pressure switch connector. Connect ohmmeter between ECM connector terminal No. 38 (White/Orange wire) and ground. If no continuity is present, go to next step. If continuity is present, check White/Orange wire for a short circuit to ground.
  3. Connect ohmmeter between A/C-heater control unit connector terminal K24 (Black wire) and ground. If no continuity is present, go to next step. If continuity is present, check Black wire for a short circuit to ground.
  4. Reconnect A/C-heater control unit connector. Ensure climate control switch is off. Connect ohmmeter (backprobe) between A/C-heater control unit connector terminal K24 (Black wire) and ground. If no continuity is present, replace ECM. If continuity is present, replace A/C-heater control unit. See A/C-HEATER SYSTEM - AUTOMATIC article in AIR CONDITIONING & HEAT section.
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