DTC P0128: Cooling System Malfunction Honda Element I

Note. If any of the DTCs listed below are stored at the same time as DTC P0128, troubleshoot those DTCs first, then recheck for P0128. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

P0112, P0113: Intake air temperature (IAT) sensor

P0116, P0117, P0118, P0125: Engine coolant temperature (ECT) sensor

P0300: Random misfire

P0301, P0302, P0303, P0304: No. 1, No. 2, No. 3, or No. 4 cylinder misfire

P0335, P0339: Crankshaft position (CKP) sensor

P2227, P2228, P2229: Barometric pressure (BARO) sensor

P2646, P2647, P2648, P2649: VTEC system

P0506, P0507: Idle control system malfunction

P0511: Idle air control (IAC) valve

DTC P0128 can occasionally set when the hood is opened while the engine is running.

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Turn the blower switch OFF.
4. Turn the A/C switch OFF.
5. Check the FAN CTRL in the DATA LIST with the HDS. Is it OFF? YES- Go to step 6 . NO- Wait until the FAN CTRL is turned off, then go to step 6 .
6. Check the ECT SENSOR in the DATA LIST with the HDS, then check the radiator fan operation. Does the radiator fan keep running when the engine coolant temperature is less than 158°F (70°C)? YES- Check the radiator fan circuit (see «RADIATOR FAN CIRCUIT TROUBLESHOOTING»(ref-220568-S40379179212006022000000) ), the radiator fan switch circuit for open (see «RADIATOR FAN SWITCH CIRCUIT TROUBLESHOOTING (»(ref-220568-S12855365752006022000000) ), the radiator fan switch circuit for short (see «RADIATOR FAN SWITCH CIRCUIT TROUBLESHOOTING (»(ref-220568-S12855365752006022000000) ), and the radiator fan switch (see «RADIATOR FAN SWITCH TEST»(ref-220568-S38064007192006022000000) ). If the circuits and the switch are OK, go to step 22 . NO- Go to step 7 .
7. Start the engine. Hold the engine speed at 3,000 RPM without load (in Park or neutral) until the radiator fan comes on, then let it idle.
8. Turn the ignition switch OFF.
9. Turn the ignition switch ON (II).
10. Do the RADIATOR FAN TEST in the INSPECTION MENU with the HDS for 20 minutes.
11. Check the ECT SENSOR in the DATA LIST with the HDS. Is about 140°F (60°C) or less, or 1.25 V or more indicated? YES- Intermittent failure, system is OK at this time. NO- Go to step 12 .
12. Turn the ignition switch OFF.
13. Cool down the engine until the coolant temperature is between 21°F (-6°C) and 104°F (40°C).
14. Replace the thermostat (see «THERMOSTAT REPLACEMENT»(ref-220567-S09071324522006022000000) ).
15. Turn the ignition switch ON (II).
16. Reset the ECM/PCM with the HDS.
17. Do the ECM/PCM idle learn procedure (see «ECM/PCM IDLE LEARN PROCEDURE»(ref-220572-S08440202922006022000000) ).
18. Start the engine. Hold the engine speed at 3,000 RPM without load (in Park or neutral) until the radiator fan comes on, then let it idle.
19. Test-drive at a steady speed between 17-75 mph (24-120 km/h) for 10 minutes.
20. Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated? YES- If DTC P0128 is indicated, check the cooling system, then go to step 1 . If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting . NO- Go to step 21 .
21. Monitor the OBD STATUS for DTC P0128 in the DTCs MENU with the HDS. Does the screen indicate PASSED? YES- Troubleshooting is complete. NO- If the screen indicates FAILED, check the cooling system, then go to step 1 . If the screen indicates NOT COMPLETED, go to step 18 and recheck.
22. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM (see «ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING»(ref-220569-S23624043112006022000000) ).
23. Cool down the engine until the coolant temperature is between 23°F (-5°C) and 95°F (35°C).
24. Start the engine. Hold the engine speed at 3,000 RPM without load (in Park or neutral) until the radiator fan comes on, then let it idle.
25. Test-drive at a steady speed between 17-75 mph (24-120 km/h) for 10 minutes.
26. Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated? YES- If DTC P0128 is indicated, check for poor connections or loose terminals at the ECT sensor and the ECM/PCM, then go to step 1 . If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting. NO- If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM (see «MAP SENSOR REPLACEMENT»(ref-220570-S17955277902006022000000) ).