A/C Condenser Fan High Speed Circuit Troubleshooting

A/C Condenser Fan High Speed Circuit Troubleshooting

NOTE:

- Do not use this troubleshooting procedure if the A/C compressor is inoperative. Refer to the symptom troubleshooting.

- Before performing symptom troubleshooting, check for powertrain DTCs; R18A1 engine, Reading and Clearing Diagnostic Trouble Codes K20Z3 engine. Reading and Clearing Diagnostic Trouble Codes

- If A/C refrigerant pressure is abnormal, the radiator fans are controlled based on engine coolant temperature. Heating and A/C System Description (With A/C)

1. Check the No. 6 (20 A) and No. 15 (7.5 A) fuses in the under-hood fuse/relay box.

Are the fuses OK?
YES - Go to step 2.

NO - Replace the fuse(s), and recheck. If the fuses blow again, check for a short in the No. 6 (20 A) and No. 15 (7.5 A) fuses circuit.


2. Remove the A/C condenser fan relay from the under-hood fuse/relay box, and test it. Testing and Inspection

Is the relay OK?
YES - Go to step 3.

NO - Replace the A/C condenser fan relay.


3. Measure the voltage between A/C condenser 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. Under-Hood Fuse/Relay Box Removal/Installation






4. Connect A/C condenser fan relay 4P socket terminals No. 1 and No. 2 with a jumper wire.

Does the A/C condenser fan run on high?
YES - Go to step 5.

NO - Replace the under-hood fuse/relay box. Under-Hood Fuse/Relay Box Removal/Installation






5. Disconnect the jumper wire.

6. Turn the ignition switch to ON (II).

7. Measure the voltage between A/C condenser fan relay 4P socket terminal No. 4 and body ground.

Is there battery voltage?
YES - Go to step 8.

NO - Go to step 15.






8. Turn the ignition switch to LOCK (0).

9. Check for continuity between fan control relay 5P socket terminal No. 2 and body ground.

Is there continuity?
YES - Go to step 10.

NO - Check for an open in the wire between the fan control relay and body ground. If the wire is OK, check for poor body ground at G301.





10. Reinstall the A/C condenser fan relay.

11. Jump the SCS line with the HDS.
NOTE: This step must be done to protect the engine control module/powertrain control module (ECM/PCM) from damage.

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

13. Connect ECM/PCM connector A (44P) terminals No. 5 and No. 21 to body ground with jumper wires.

14. Turn the ignition switch to ON (II).

Does the A/C condenser fan run on high?
YES - Check for loose wires or poor connections at ECM/PCM connector A (44P) terminal No. 5. If the connections are good, substitute a known-good ECM/PCM; R18A1 engine, Reading and Clearing Diagnostic Trouble Codes K20Z3 engine, Reading and Clearing Diagnostic Trouble Codes and recheck. If the symptom/indication goes away, replace the original ECM.

NO - Repair an open in the wire between the A/C condenser fan relay and the ECM/PCM.






15. Turn the ignition switch to LOCK (0).

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

17. Turn the ignition switch to ON (II).

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

Is there battery voltage?
YES - Go to step 19.

NO - Replace the under-hood fuse/relay box. Under-Hood Fuse/Relay Box Removal/Installation






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

Is there current flow in only one direction?
YES - Replace the under-hood fuse/relay box. Under-Hood Fuse/Relay Box Removal/Installation

NO - Replace A/C diode B.