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Home/Honda/Crosstour/Honda Crosstour I (2012-2012)/Repair manual/Testing & Diagnostics/DTC P0128: Cooling System Malfunction
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DTC P0128: Cooling System Malfunction Honda Crosstour I

Testing & Diagnostics ~711 words

Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION (+).

  1. Turn the ignition switch to ON (II).
  2. Clear the DTC with the HAS.
  3. Make sure the blower switch is off.
  4. Check the FAN CTRL in the DATA LIST with the HAS. Is it OFF? YES -Go to next step. NO -Wait until the FAN CTRL and FAN LOW CNTRL are off, then go to next step.
  5. Check the radiator fan operation. Does the radiator fan keep running? YES -Check the radiator fan high speed circuit (see «RADIATOR FAN HIGH SPEED CIRCUIT TROUBLESHOOTING»(ref-360096-S38492085832010042600000) (+) and the radiator fan relay (see «POWER RELAY TEST»(ref-360075-S10513756052010042600000) (+). If the circuits and the relay are OK, go to step 19 . NO -Go to next step.
  6. Let the engine cool until the coolant temperature is 104°F (40°C) or less.
  7. Note the value of ECT SENSOR 1 and ECT SENSOR 2 in the DATA LIST with the HAS.
  8. Start the engine, and let it idle.
  9. Let the engine idle until ECT SENSOR 1 goes up 34 °F (19 °C) or more from the recorded temperature.
  10. Check ECT SENSOR 2 in the DATA LIST with the HAS.
  11. Compare the recorded value of ECT SENSOR 2 and the present value of ECT SENSOR 2. Did the temperature rise 9 °F (5 °C) or more? YES -Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at ECT sensor 1, ECT sensor 2, and the PCM. NO -Test the thermostat (see «FAN MOTOR TEST»(ref-360063-S29251781852010042600000) (+) then go to next step.
  12. Turn the ignition switch to ON (II).
  13. Reset the PCM with the HAS.
  14. Let the engine cool until the coolant temperature is between 21 °F (-6 °C) and 104 °F (40 °C).
  15. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(ref-360079-S22847966492010042600000) (+).
  16. Test-drive at a steady speed between 15 - 75 mph (24 - 120 km/h) for 10 minutes.
  17. Check for Pending or Confirmed DTCs with the HAS. Is DTC P0128 indicated? YES -Check the cooling the system, then go to step 19 . NO -Go to next step.
  18. Monitor the OBD STATUS for DTC P0128 in the DTCs MENU with the HAS. Does the HAS indicate PASSED? YES -Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 17 , go to the indicated DTC's troubleshooting. NO -If the HAS indicates FAILED, check the cooling system, then go to 19 . If the HAS indicates NOT COMPLETED, go to step 14 .
  19. Update the PCM if it does not have the latest software (see «PCM UPDATE»(ref-360080-S11980508702010042600000) (+) or substitute a known-good PCM (see «SUBSTITUTING THE PCM»(ref-360056-S32194616542010042600000) (+).
  20. Let the engine cool until the coolant temperature is between 21 °F (-6 °C) and 104 °F (40 °C).
  21. Start the engine. Hold the engine speed at 3,000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.
  22. Test-drive at a steady speed between 15 - 75 mph (24 - 120 km/h) for 10 minutes.
  23. Check for Pending or Confirmed DTCs with the HAS. Is DTC P0128 indicated? YES -Check for poor connections or loose terminals at ECT sensor 1, ECT sensor 2, and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(ref-360056-S32194616542010042600000) (+) then go to step 20 . If the PCM was substituted, go to step 1 . NO -Go to next step.
  24. Monitor the OBD STATUS for DTC P0128 in the DTCs MENU with the HAS. Does the HAS indicate PASSED? YES -If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see «PCM REPLACEMENT»(ref-360080-S27881728262010042600000) (+). If any other Pending or Confirmed DTCs were indicated in step 23 , go to the indicated DTC's troubleshooting. NO -If the HAS indicates FAILED, check for poor connections or loose terminals at ECT sensor 1, ECT sensor 2, and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(ref-360056-S32194616542010042600000) (+) then go to step 20 . If the PCM was substituted, go to step 1 . If the HAS indicates NOT COMPLETED, go to step 20 .

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