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Home >> Volvo >> 1995 >> 850 Base, 4D Sedan, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Turbo >> Diagnostic Trouble Code Testing >> MOTRONIC 4.3 Control System >> Code 2-2-5: A/C Pressure Sensor Signal

Code 2-2-5: A/C Pressure Sensor Signal

  1. If fault is permanent and signal is too high, go to next step. If fault is permanent and signal is too low, go to step 7). If fault is intermittent and signal is too high, go to step 8). If fault is intermittent and signal is too low, go to step 9).
  2. Turn ignition off. Wait about 2 minutes. Disconnect A/C pressure sensor. Connect an ohmmeter between A/C pressure sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to step 4). If ohmmeter does not read about zero ohms, go to next step.
  3. Turn ignition off. Disconnect A/C pressure sensor connector. Check ECM connector for oxidation and poor terminal contact. Repair as necessary. Reconnect ECM connector. Connect an ohmmeter between A/C pressure sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check wiring between A/C pressure sensor connector terminal No. 1 and ECM terminal B28 for an open circuit.
  4. Turn ignition on. Disconnect A/C pressure sensor connector. Connect a voltmeter between A/C pressure sensor connector terminal No. 2 and ground. If voltmeter reads about 5 volts, go to step 6). If voltmeter reads about zero volts, go to next step. If voltmeter reads more than about 5 volts, check wiring between A/C pressure sensor connector terminal No. 2 and ECM terminal B9 for a short to voltage.
  5. Turn ignition off. Disconnect A/C pressure sensor. Ensure ECM connector terminals are clean and free of oxidation. Repair as necessary. Reconnect ECM. Turn ignition on. Connect voltmeter between A/C pressure sensor connector terminal No. 2 and ground. If voltmeter reads about 5 volts, cause of code is poor contact in ECM connector. If voltmeter does not read about 5 volts, check wiring between A/C pressure sensor connector terminal No. 2 and ECM terminal B9 for an open circuit.
  6. Turn ignition off. Reconnect A/C pressure sensor. Start engine and idle for 15 seconds. Turn A/C and blower on. If A/C APPROVED parameter displays YES on Volvo Scan Tool (998-8686 ), cause of code is poor contact in A/C pressure sensor connector. If parameter displays NO, retest using new A/C pressure sensor.
  7. If fault is permanent and signal is too low, turn ignition off. Disconnect A/C pressure sensor. Turn ignition on. Connect voltmeter between A/C pressure sensor connector terminal No. 2 and ground. If voltmeter reads about 5 volts, retest using new A/C pressure sensor. If voltmeter does not read about 5 volts, check wiring between A/C pressure sensor connector terminal No. 2 and ECM terminal B9 for a short circuit to ground.
  8. If fault is intermittent and signal is too high, check A/C pressure sensor and ECM connectors for loose connection or contact resistance. Check wiring between A/C pressure sensor connector terminal No. 1 and ECM terminal B28 for an intermittent open circuit. Also check wiring between A/C pressure sensor connector terminal No. 2 and ECM terminal B9 for an intermittent open circuit or short circuit to ground.
  9. If fault is intermittent and signal is too low, check wiring between A/C pressure sensor connector terminal No. 2 and ECM terminal B9 for an intermittent short circuit to ground. Repair as necessary.
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