Symptom Chart

NOTE: Some PCM DTCs may inhibit air conditioning (A/C) operation. If any PCM DTCs are retrieved, diagnose those first. Refer to Introduction - Gasoline Engines article.

SYMPTOM CHART

Condition	Possible Sources	Action
No communication with the electronic automatic temperature control (EATC) or electronic manual temperature control (EMTC) module	Fuse(s) Circuitry open EATC or EMTC module communication network	REFER to MODULE COMMUNICATIONS NETWORK article.
The air inlet door is inoperative	Circuitry open/shorted Door actuator Air inlet door binding or stuck EMTC module or EATC module	Go to Pinpoint Test G .
Incorrect/erratic direction of airflow from outlets	Circuitry open/shorted Door actuator Mode door binding or stuck EMTC module or EATC module	Go to Pinpoint Test H .
The EATC system is inoperative, intermittent or incorrect operation	Fuse(s) Circuitry open	Go to Pinpoint Test I .
Insufficient, erratic or no heat	Low engine coolant level Engine overheating Plugged or partially plugged heater core Temperature blend door is binding or stuck Temperature blend door actuator Heater hose is kinked or binding	Go to Pinpoint Test J .
The air conditioning (A/C) is inoperative/does not operate correctly	Fuse(s) Circuitry open A/C system discharged/low charge PCM EATC module EMTC module A/C clutch relay A/C compressor clutch air gap A/C pressure transducer Evaporator discharge temperature sensor A/C clutch field coil Battery junction box (BJB)	Go to Pinpoint Test K .
The A/C is always on	Circuitry shorted PCM EATC module EMTC module A/C clutch relay A/C compressor clutch air gap A/C pressure transducer Evaporator discharge temperature sensor A/C clutch field coil	Go to Pinpoint Test L .
Temperature control is inoperative/does not operate correctly	Circuitry open/shorted EMTC module EATC module Temperature blend door is binding or stuck Temperature blend door actuator	Go to Pinpoint Test M .
The blower motor is inoperative - EMTC	Fuse(s) Circuitry open A/C blower motor switch Blower motor relay A/C blower motor EMTC module BJB	Go to Pinpoint Test N .
The blower motor does not operate correctly - EMTC	Circuitry open/shorted A/C blower motor resistor A/C blower motor switch	Go to Pinpoint Test O .
The blower motor is inoperative - EATC	Fuse(s) Circuitry short/open Blower motor relay A/C blower motor EATC module A/C blower motor speed control BJB	Go to Pinpoint Test P .
The blower motor does not operate correctly - EATC	Circuitry open/shorted A/C blower motor speed control EATC module	Go to Pinpoint Test Q .
The auxiliary blower motor is inoperative	Fuse(s) Circuitry open Auxiliary blower motor relay 1 Auxiliary blower motor resistor Auxiliary blower motor EMTC module EATC module	Go to Pinpoint Test R .
The auxiliary blower motor does not operate correctly	Fuse(s) Circuitry open/shorted Auxiliary blower motor relay 1 Auxiliary blower motor relay 2 Auxiliary blower motor relay 3 Auxiliary blower motor resistor Rear auxiliary control EMTC module EATC module	If the auxiliary blower motor does not operate correctly from both the front and rear auxiliary controls, go to Pinpoint Test S . If the auxiliary blower motor does not operate correctly from the rear auxiliary controls only, go to Pinpoint Test V . If the auxiliary blower motor does not operate correctly from the front auxiliary controls only, CARRY OUT the Electronic Automatic Temperature Control (EATC) Module and Electronic Manual Temperature Control (EMTC) Module Cold Boot Process. If the condition returns, INSTALL a new EMTC/EATC module. REFER to CLIMATE CONTROL article. TEST the system for normal operation.
The auxiliary temperature control is inoperative/does not operate correctly using the front/rear auxiliary climate controls	Circuitry open/shorted Auxiliary blend door actuator EMTC module EATC module	If the auxiliary temperature control is inoperative/does not operate correctly from both the front and rear auxiliary controls, go to Pinpoint Test T . If the auxiliary temperature control is inoperative/does not operate correctly from the rear auxiliary controls only, go to Pinpoint Test V . If the auxiliary temperature control is inoperative/does not operate correctly from the front auxiliary controls only, CARRY OUT the Electronic Automatic Temperature Control (EATC) Module and Electronic Manual Temperature Control (EMTC) Module Cold Boot Process. If the condition returns, INSTALL a new EMTC/EATC module. REFER To CLIMATE CONTROL article. TEST the system for normal operation.
The auxiliary panel/floor control is inoperative/does not operate correctly using the front/rear auxiliary climate controls	Circuitry open/shorted Auxiliary mode door actuator EMTC module EATC module	If the auxiliary panel/floor control is inoperative/does not operate correctly from both the front and rear auxiliary controls, go to Pinpoint Test U . If the auxiliary panel/floor control is inoperative/does not operate correctly from the rear auxiliary controls only, go to Pinpoint Test V . If the auxiliary panel/floor control is inoperative/does not operate correctly from the front auxiliary controls only, CARRY OUT the Electronic Automatic Temperature Control (EATC) Module and Electronic Manual Temperature Control (EMTC) Module Cold Boot Process. If the condition returns, INSTALL a new EMTC/EATC module. REFER to CLIMATE CONTROL article. TEST the system for normal operation.
The auxiliary temperature, panel/floor and blower motor controls are inoperative/do not operate correctly using the front/rear auxiliary climate controls	Circuitry open/shorted Rear auxiliary control EMTC module EATC module	Go to Pinpoint Test V .
The dual temperature control is inoperative/does not operate correctly	Temperature blend door/actuator broken/binding EATC module Low A/C refrigerant charge	CHECK that the A/C system pressure is above 290 kPa (42 psi). If the pressure is below 290 kPa (42 psi), REFER to Fluorescent Dye Leak Detection . CHECK the temperature blend doors/actuators for a binding or broken condition. If no condition is found, INSTALL a new EMTC/EATC module.
The temperature set point does not repeat after turning the ignition switch OFF	Fuse Circuitry short/open EATC module	VERIFY smart junction box (SJB) fuse 15 (10A) is OK. If OK, CHECK circuit SBP15 (WH/RD) for a short or open and repair as necessary. If OK, INSTALL a new EATC module.
The temperature display will not switch between Celsius and Fahrenheit	EATC module Instrument cluster (IC) module	If the instrument cluster does not switch between English and Metric, refer to INSTRUMENT CLUSTER AND PANEL ILLUMINATION article and diagnose. If only the EATC module does not switch between English and Metric, INSTALL a new EATC module.
Inaccurate external temperature display	EATC module Ambient temperature sensor	REFER to Description and Operation of the EATC External Temperature Display. If the external temperature display is not operating as described and no DTC is present, REMOVE the sensor from the vehicle (leave connected) and submerge in ice bath (ice water with ice). While the sensor is submerged, CARRY OUT the Electronic Automatic Temperature Control (EATC) Module and Electronic Manual Temperature Control (EMTC) Module Cold Boot process. After the cold boot, CHECK the external temperature display. The reading should be within 3 degrees of freezing (i.e. 0°C [32°F]). If the display is still incorrect, INSTALL a new external temperature sensor and retest the system for normal operation. If the condition persists (and there are still no DTCs present), INSTALL a new EATC module. REFER to CLIMATE CONTROL article. TEST the system for normal operation.
A/C pressure relief valve discharging	High system pressure A/C pressure relief valve	CHECK the high side system pressure. If the pressure is below the A/C pressure relief valve open pressure, REPLACE the A/C pressure relief valve. If the system pressure is above the A/C pressure relief valve open pressure, REPAIR the system for a restriction.