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Home >> Volvo >> 1998 >> V70 Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Tests >> DTC P0530/EFI 225, DTC P0531/EFI 225, DTC P0532/EFI 225 & DTC P0533/EFI 225 (Non-Turbo) >> Diagnosis (Signal Too Low, Permanent Fault)

Diagnosis (Signal Too Low, Permanent Fault)

  1. Checking power cable Turn ignition off. Disconnect the air conditioning (A/C) pressure sensor. Turn ignition on. Connect a voltmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The voltmeter should read 5V. If reading is OK, go to step  2. If value is lower, go to step  4. If value is higher, A/C pressure sensor power cable is connected inside ECM to fuel tank pressure sensor and accelerometer power cables. If anything happens to any of these cables, all 3 will be affected. They should always be checked. Check cables for a short-circuit between:
    • Accelerometer terminal 1 and ECM terminal No. B1
    • Air conditioning (A/C) pressure sensor terminal 3 and ECM terminal No. B29
    • Tank pressure sensor terminal 1 and ECM terminal B15
    Then, go to step  9.
  2. Checking signal cable resistance. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 2 and ground. The ohmmeter should read approximately 10,000 ohms. If reading is OK, go to step  3. If reading is incorrect, check cable between air conditioning (A/C) pressure sensor terminal 2 and ECM terminal No. B9 for a short-circuit to ground. Go to step  9.
  3. Checking the air conditioning (A/C) pressure sensor. Turn ignition off. Connect air conditioning (A/C) pressure sensor. Start the engine and idle it. Turn air conditioning (A/C) switch on. Turn blower fan on. Select Volvo Scan Tool, or aftermarket scan tool, to read off the value of the air conditioning (A/C) pressure sensor signal. Voltage should increase when the air conditioning (A/C) compressor starts. If reading is NOT OK, try a new A/C pressure sensor. Go to step  9. If reading is OK, the cause of the DTC has been loose connections in the air conditioning (A/C) pressure sensor connector. Check connector for contact resistance and oxidation and remedy. Go to step  9.
  4. Checking power cable resistance to ground. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Wait for approximately 150 seconds (cars with immobilizer 245 seconds). Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read approximately 200-1500 ohms. If reading is OK, go to step  5. If reading is not OK, go to step  8.
    5. NOTE: Vehicle with EVAP leak diagnostic will be equipped with a fuel tank pressure sensor.
  5. Checking accelerometer. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Disconnect accelerometer. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read about 200-1500 ohms. If reading is OK, try a new accelerometer. Go to step  9. If reading is NOT OK on vehicles with EVAP leak diagnostic, go to step  6. If reading is NOT OK on vehicles without EVAP leak diagnostic, go to step  7.
    6. NOTE: Vehicle with EVAP leak diagnostic will be equipped with a fuel tank pressure sensor.
  6. Checking fuel tank pressure sensor. Turn ignition off. Disconnect air conditioning (A/C) pressure sensor and accelerometer. Disconnect fuel tank pressure sensor. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read approximately 200-1500 ohms. If reading is OK, try a new fuel tank pressure sensor. Go to step  9. If reading is NOT OK, go to  7.
  7. Checking power cables. The A/C pressure sensor power cable is connected inside the ECM to the tank pressure sensor and accelerometer power cables. If anything happens to any of these cables, all 3 will be affected. Check cables for a short-circuit to ground between:
    • Accelerometer terminal 1 and ECM terminal No. B1
    • Air conditioning (A/C) pressure sensor terminal 3 and ECM terminal No. B29
    • Tank pressure sensor terminal 1 and ECM terminal No. B15
    Go to step  9.
  8. Checking ECM connector. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Check ECM connector for contact resistance and oxidation and remedy. With ECM connected, connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read approximately 200-1500 ohms. If reading is OK, DTC was caused by loose connections in ECM connector. Go to step  9. If reading is incorrect, check wire between air conditioning (A/C) pressure sensor connector 3 and ECM terminal No. B29 for an open circuit. Go to step  9
  9. Verification. After carrying out the repair, check that the fault has been remedied as follows: Turn ignition off. Air conditioning (A/C) pressure sensor and ECM connected. Start the engine and idle it. Air conditioning (A/C) switch on. Blower fan on. Wait until the air conditioning (A/C) compressor has started. Select Volvo Scan Tool, or aftermarket scan tool, to read off DTCs. If EFI-225 is stored it should have intermittent status.
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