Radiator and A/C Condenser Fan Low Speed Circuit Troubleshooting

NOTE:


1.Check the No. 7 (20 A)*1 or (30 A)*2 fuse in the under-hood fuse/relay box, and the No. 36 (10 A) fuse in the under-dash fuse/relay box.

*1: All M/T models and A/T model of K20Z2 engine 
*2: A/T models except K20Z2 engine 

Are the fuses OK?


YES - Go to 2.


NO - Replace the fuses, and recheck.n


2.Remove the radiator fan relay from the under-hood fuse/relay box, and test it.

Is the relay OK?


YES - Go to 3.


NO - Replace the  radiator fan relay.n


3.Connect the HDS to the DLC.

4.Turn the ignition switch ON (II).

5.Turn on the A/C on the HVAC control unit.

6.Check the FAN LOW CTRL in the PGM-FI Data List with the HDS.

Is the FAN LOW CTRL on?


YES - Go to 7.


NO - Substitute a known-good ECM/PCM, except K20Z2 engine, K20Z2 engine and retest. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM, except K20Z2 engine, K20Z2 engine.n

7.Measure the voltage between the radiator fan relay 4P socket terminal No. 1 and body ground.

 

Is there battery voltage?


YES - Go to 8.


NO - Repace the under-hood fuse/relay box.n


8.Connect the radiator fan relay 4P socket terminals No. 1 and No. 2 with a jumper wire.

 

Do the A/C condenser and radiator fans run on low?


YES - Go to 9.


NO - Go to 17.


9.Disconnect the jumper wire.

10.Turn the ignition switch ON (II).

11.Measure the voltage between the radiator fan relay 4P socket terminal No. 3 and body ground.

 

Is there battery voltage?


YES - Go to 12.


NO - Go to 35.

12.Turn the ignition switch OFF.

13.Reinstall the radiator fan relay.

14.Disconnect ECM/PCM connector A (44P).

15.Connect the ECM/PCM connector A (44P) terminal No. 4 to body ground with a jumper wire.

 

16.Turn the ignition switch ON (II).

Do the A/C condenser and radiator fans run on low?


YES - Check for loose wires or poor connections at ECM/PCM connector A (44P) terminal No. 4. If the connections are good, substitute a known-good ECM/PCM, and recheck. If the symptom/indication goes away, replace the original ECM/PCM, then do the ECM/PCM idle learn procedure, except K20Z2 engine, K20Z2 engine.n


NO - Repair open in the wire between the radiator fan relay and the ECM/PCM.n


17.Disconnect the jumper wire.

18.Reinstall the radiator fan relay.

19.Disconnect the radiator fan 2P connector.

20.Turn the ignition switch ON (II), then set the A/C button and fan control dial ON.

21.Measure the voltage between the radiator fan 2P connector terminal No. 2 and body ground.

 

Is there battery voltage?


YES - Go to 22.


NO - Repair open in the wire between the radiator fan relay and the radiator fan.n


22.Set the A/C button and fan control dial OFF, then turn the ignition switch OFF.

23.Reconnect the radiator fan 2P connector.

24.Connect the radiator fan 2P connector terminal No. 1 to body ground with a jumper wire.

 

25.Turn the ignition switch ON (II), then set the A/C button and fan control dial ON.

Does the radiator fan run?


YES - Go to 26.


NO - Replace the radiator fan motor.n

26.Set the A/C button and fan control dial OFF, then turn the ignition switch OFF.

27.Disconnect the jumper wire.

28.Remove the fan control relay from the under-hood relay box, and test it.

Is the relay OK?


YES - Go to 29.


NO - Replace the fan control relay.n


29.Turn the ignition switch ON (II), then set the A/C button and fan control dial ON.

30.Measure the voltage between the fan control relay 5P socket terminal No. 1 and body ground.

 

Is there battery voltage?


YES - Go to 31.


NO - Repair open in the wire between the radiator fan and the fan control relay.n


31.Set the A/C button and fan control dial OFF, then turn the ignition switch OFF.

32.Disconnect the A/C condenser fan 2P connector.

33.Check for continuity between the fan control relay 5P socket terminal No. 4 and the A/C condenser fan 2P connector terminal No. 2.

 

Is there continuity?


YES - Go to 34.


NO - Repair open in the wire between the fan control relay and the A/C condenser fan.n


34.Check for continuity between the A/C condenser fan 2P connector terminal No. 1 and body ground.

 

Is there continuity?


YES - Replace the A/C condenser fan motor.n


NO - Check for an open in the wire between the A/C condenser fan and body ground. If the wire is OK, check for poor ground at G301.n

35.Turn the ignition switch OFF.

36.Remove A/C diode A from the under-hood fuse/relay box.

37.Using the diode setting () on a DVOM, check for current flow in both directions between the A/C diode A terminals No. 1 and No. 2.

 

Is there current flow in only one direction?


YES - Go to 38.


NO - Replace A/C diode A.n


38.Turn the ignition switch ON (II).

39.Measure the voltage between the A/C diode A 2P socket terminal No. 2 and body ground.

 

Is there battery voltage?


YES - Replace the under-hood fuse/relay box.n


NO - Repair open in the wire between the No. 36 fuse in the under-dash fuse/relay box and A/C diode A.n