Scheme 1
Symptom Troubleshooting Index
| Symptom | Diagnostic Procedure |
|---|---|
| Engine overheats | Inspect the water pump (see WATER PUMP INSPECTION ). Check the thermostat (see THERMOSTAT TEST ). Check for any engine coolant leakage (from gaskets, hoses, O-rings, etc.). Check for dirt, leaves, or insects on radiator and A/C condenser. Check for a damaged or deformed fan shroud. Check for plugged or deteriorated radiator hoses. Check the radiator cap (see RADIATOR CAP TEST ). Inspect the fan motors (see FAN MOTOR TEST ) or fan relays (see POWER RELAY TEST ). Check for plugged heater core or hoses. Check the coolant level. Check for deteriorated coolant. Check for a damaged cylinder head gasket. |
| The radiator fan runs at low speed, but does not run at high speed when the engine coolant temperature is above 206°F (97°C) | Radiator fan high speed circuit troubleshooting (see RADIATOR FAN HIGH SPEED CIRCUIT TROUBLESHOOTING ). |
| With the A/C off and the engine coolant temperature at 206°F (97°C) or below, the A/C condenser fan runs at high speed and the radiator fan does not run. When the engine coolant temperature is above 206°F (97°C), both fans run at high speed | Remove the fan control relay, and test it. If the relay is faulty, replace it. If the relay is OK, repair a short in the wire between fan control relay 5P socket terminal No. 1 and A/C condenser fan motor 2P connector terminal No. 1. |
| Both the radiator fan and the A/C condenser fan run at high speed with the ignition switch ON (II), the A/C off, and the engine coolant temperature below 204°F (95°C) | Check for a short in the wire between radiator fan relay 4P socket terminal No. 4 and PCM connector terminal B28. |
| Both the radiator fan and the A/C condenser fan run at low speed with the ignition switch ON (II) and the A/C off | Check for a short in the wire between A/C condenser fan relay 4P socket terminal No. 4 and PCM connector terminal B14. |
| Both the radiator fan and the A/C condenser fan do not run at low speed with the A/C on | Radiator and A/C condenser fans low speed circuit troubleshooting (see RADIATOR AND A/C CONDENSER FAN LOW SPEED CIRCUIT TROUBLESHOOTING ). |
| The A/C condenser fan does not run at all. The radiator fan does not run at low speed, but it runs at high speed | A/C condenser fans high speed circuit troubleshooting (see RADIATOR AND A/C CONDENSER FAN HIGH SPEED CIRCUIT TROUBLESHOOTING ). |
| Both the radiator fan and the A/C condenser fan do not run at high speed when the engine coolant temperature is above 206°F (97°C) | Check for an open in the wire between radiator fan relay 4P socket terminal No. 4 and PCM connector terminal A7. |
SYMPTOM TROUBLESHOOTING INDEX
Scheme 2
Scheme 3
Scheme 4
Scheme 5
- Remove the radiator fan relay from the under-hood fuse/relay box and test it (see «POWER RELAY TEST»(/acura/mdx/i-2000-2006/remont/body-electrical/#relays__power-relay-test) ). Is the relay OK? YES - Go to step 2. NO - Replace the radiator fan relay.
- Turn the ignition switch ON (II).
- Measure the voltage between radiator fan relay 4P socket terminal No. 1 and body ground. Is there battery voltage? YES - Go to step 4. NO - Replace the under-hood fuse/relay box.
- Connect radiator fan relay 4P socket terminals No. 1 and No. 2 with a jumper wire. Does the radiator fan run at high speed? YES - Go to step 5. NO - -Repair an open in the wire between radiator fan relay 4P socket terminal No. 2 and radiator fan motor 2P connector terminal No. 2.
- Measure voltage between radiator fan relay 4P socket terminal No. 3 and body ground. Is there battery voltage? YES - Repair an open in the wire between radiator fan relay 4P socket terminal No. 4 and the PCM. NO - Repair an open in the wire between radiator fan relay 4P socket terminal No. 3 and the air fuel ratio sensor relay 4P socket terminal No. 2.