F5C EGR Valve Circuit - No Reaction Needed If Failure Isnt Present Again After Short Time. Replace Engine Controller If Fault Persists. Follow The Appropriate Service Tool Procedure To Restore Self Learning Parameters Engine
If Inadequate air flow is problematic, so clogged air filters, evaporator core air flow restricted, faulty blower fan motors, defective blower switch or faulty wiring or loose connections.