B1241
DTC Troubleshooting: B1241 (F and A/C)
DTC B1241 or DTC indicator F and A/C:
A Problem in the Blower Motor Circuit
1. Clear the DTCs with the HDS.
2. Turn the ignition switch to LOCK (0) and then back to ON (II).
3. Do the self-diagnostic function with the HDS or the climate control unit.
4. Check for DTCs.
Is DTC B1241 or F and A/C indicated?
YES -
Go to step 5.
NO -
Intermittent failure, check for loose wires or poor connections in the blower motor circuit.
5. Turn the ignition switch to LOCK (0).
6. Check the No. 10 (7.5 A) and No. 57 (30 A) fuses in the under-dash fuse/relay box.
Are the fuses OK?
YES -
Go to step 7.
NO -
Replace the fuse(s), and recheck. If fuse(s) blow again, check for a short in the No. 10 (7.5 A) and No. 57 (30 A) fuses circuit.
7. Disconnect the blower motor 2P connector.
8. Turn the ignition switch to ON (II).
9. Measure the voltage between blower motor 2P connector terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to step 10.
NO -
Go to step 30.
10. Turn the ignition switch to LOCK (0).
11. Reconnect the blower motor 2P connector.
12. Connect blower motor 2P connector terminal No. 2 to body ground with a jumper wire.
13. Turn the ignition switch to ON (II).
Does the blower motor run?
YES -
Go to step 14.
NO -
Replace the blower motor Blower Unit Component Replacement.
14. Turn the ignition switch to LOCK (0).
15. Disconnect the jumper wire.
16. Disconnect the power transistor 4P connector.
17. Check for continuity between power transistor 4P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Go to step 18.
NO -
Check for an open in the BLK wire between the power transistor and body ground. If the wire is OK, check for poor body ground at G502.
18. Connect power transistor 4P connector terminals No. 2 and No. 4 with a jumper wire.
19. Turn the ignition switch to ON (II).
Does the blower motor run at high speed?
YES -
Go to step 20.
NO -
Repair an open in the BLU wire between the power transistor and the blower motor.
20. Turn the ignition switch to LOCK (0).
21. Disconnect the jumper wire.
22. Disconnect the climate control unit 36P connector.
23. Check for continuity between body ground and climate control unit 36P connector terminals No. 15 and No. 34 individually.
Is there continuity?
YES -
Repair a short to body ground in the wire(s) between the climate control unit and the power transistor.
NO -
Go to step 24.
24. Check for continuity between the following terminals of the climate control unit 36P connector and the power transistor 4P connector.
Is there continuity?
YES -
Go to step 25.
NO -
Repair an open in the wire(s) between the climate control unit and the power transistor.
25. Turn the ignition switch to ON (II).
26. Measure the voltage between body ground and climate control unit 36P connector terminals No. 15 and No. 34 individually.
Is there voltage?
YES -
Repair a short to power in the wire(s).
NO -
Go to step 27.
27. Turn the ignition switch to LOCK (0).
28. Reconnect the climate control unit 36P connector.
29. Test the power transistor Testing and Inspection.
Is the power transistor OK?
YES -
Check for loose wires or poor connections at the climate control unit 36P connector and at the power transistor 4P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit Climate Control Unit Removal/Installation.
NO -
Replace the power transistor Testing and Inspection.
NOTE: If the power transistor is faulty, check the blower motor for damage. If necessary, replace the blower motor Blower Unit Component Replacement.
30. Turn the ignition switch to LOCK (0).
31. Remove the blower motor relay from the under-dash fuse/relay box, and test it Testing and Inspection.
Is the relay OK?
YES -
Go to step 32.
NO -
Replace the blower motor relay.
32. Measure the voltage between blower motor relay 4P socket terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to step 33.
NO -
Replace the under-dash fuse/relay box.
- USA models Under-Dash Fuse/Relay Box Removal and Installation (USA Models)
- Canada models Under-Dash Fuse/Relay Box Removal and Installation (Canada Models)
33. Turn the ignition switch to ON (II).
34. Measure the voltage between blower motor relay 4P socket terminal No. 4 and body ground.
Is there battery voltage?
YES -
Go to step 35.
NO -
Replace the under-dash fuse/relay box.
- USA models Under-Dash Fuse/Relay Box Removal and Installation (USA Models)
- Canada models Under-Dash Fuse/Relay Box Removal and Installation (Canada Models)
35. Turn the ignition switch to LOCK (0).
36. Check for continuity between blower motor relay 4P socket terminal No. 3 and body ground.
Is there continuity?
YES -
Repair an open in the WHT wire between the blower motor relay and the blower motor.
NO -
Check for an open in the wire between the blower motor relay and body ground. If the wire is OK, check for poor ground at G501.