SymptomDiagnostic procedure Also check for
21-18Climate Control
Symptom Troubleshooting Index (cont’d)
–
–
Warm air comes out of
the vents, and there is
frost on the expansion
valve
Probable cause: The expansion valve is stuck
closed
Replace the expansion valve (see page 21-80)
HVAC DTCs (see page 21-9)
Check the old expansion valve
for contamination. If
contaminants are found,
replace the A/C system
component that caused the
contamination
The temperature of the
liquid line is the same
on both sides of the
expansion valve, and
the evaporator coil or
suction line has heavy
condensation Probable cause: The expansion valve is stuck
open
Replace the expansion valve (see page 21-80)
HVAC DTCs (see page 21-9)
Check the old expansion valve
for contamination. If
contaminants are found,
replace the A/C system
component that caused the
contamination
Warm air comes out of
the vents, but
operation is normal
otherwise Probable cause: Compressor failure
Do the A/C system test (see page 21-99), and
correct any problems. If necessary, replace the
compressor (see page 21-83) HVAC DTCs (see page 21-9)
Add refrigerant oil depending
on the part you replaced
(see page 21-7)
Driver’s and
passenger’s side vent
temperatures vary by
more than 11 °C (20 °F) Probable causes: The recirculation control door
or the air mix door is malfunctioning
Do the following troubleshooting:
Recirculation control motor test (see page
21-74)
Air mix control motor test (see page 21-72) HVAC DTCs (see page 21-9)
Poor or loose connections at the
terminals
Insufficient heating 1. 2.
3.
4.
5.
6.
7.Check the coolant level (see page 10-7)
Check the radiator cap (see page 10-4)
Check the coolant temperature during normal
operation
Check the heater core inlet hose temperature:
If it is COLD, check for restrictions in the hose,
a damaged or leaking thermostat, or a
damaged or leaking water pump
If it is HOT, check for restrictions in the
heater core. Back flush or replace the heater
core
Do the air mix control motor test (see page
21-72)
Check the blower motor unit for obstructions
Check for air leaks around the ducts and vents HVAC DTCs (see page 21-9)
Damaged cylinder head gasket
08/08/21 14:40:59 61SNR030_210_0019
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