Diagnostic Procedure

NO. 23 A/C DOES NOT WORK SUFFICIENTLY (SKYACTIV-G 2.5T) DIAGNOSTIC PROCEDURE

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM, INSTRUMENT CLUSTER AND CLIMATE CONTROL UNIT DTC Retrieve the PCM, instrument cluster and climate control unit DTCs using the M-MDS. (See On-Board Diagnostic Test .) (See DTC INSPECTION [INSTRUMENT CLUSTER] .) (See DTC DISPLAY [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)] .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [PCM (SKYACTIV-G 2.5T)] .) (See DTC TABLE [INSTRUMENT CLUSTER] .) (See DTC TABLE [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)] .)
1		No	Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS A/C RELAY CONTROL SIGNAL OR A/C REQUEST SIGNAL Access the PCM simulation item ACCS using the M-MDS. (See On-Board Diagnostic Test .) Start the engine and idle it. Turn the ACCS PID to ON from OFF using the M-MDS simulation function. Is the magnetic clutch engaged?	Yes	Go to the next step.
2		No	Go to Step 8.
3	DETERMINE IF MALFUNCTION CAUSE IS REFRIGERANT PRESSURE SENSOR OR OTHER Access the PCM PID AC_REQ using the M-MDS. (See On-Board Diagnostic Test .) Monitor the AC_REQ PID while turning on and off the air conditioner with switch on the control panel. Is the AC_REQ PID value normal? (See PCM Inspection .)	Yes	Go to the next step.
3		No	Go to Step 5.
4	INSPECT REFRIGERANT PRESSURE SENSOR Inspect the refrigerant pressure sensor. (See REFRIGERANT PRESSURE SENSOR INSPECTION .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
4		No	Inspect the following: Refrigerant charging amount A/C compressor seized Repair or replace the malfunctioning part according to the inspection results if necessary.
5	DETERMINE IF MALFUNCTION CAUSE IS EVAPORATOR TEMPERATURE SENSOR OR OTHER Measure the voltage at the front climate control unit terminal 1P (wiring harness-side). Is the voltage normal? (See FRONT CLIMATE CONTROL UNIT INSPECTION .)	Yes	Go to Step 8.
5		No	Go to the next step.
6	INSPECT EVAPORATOR TEMPERATURE SENSOR Inspect the evaporator temperature sensor. (See EVAPORATOR TEMPERATURE SENSOR INSPECTION .) Is there any malfunction?	Yes	Replace the evaporator temperature sensor. (See EVAPORATOR TEMPERATURE SENSOR REMOVAL/INSTALLATION .)
6		No	Inspect for short or open circuit between the following terminals: Evaporator temperature sensor terminal B-Front climate control unit terminal 1P (front climate control unit type A) Evaporator temperature sensor terminal B-Front climate control unit terminal 1E (front climate control unit type B) Evaporator temperature sensor terminal A-Front climate control unit terminal 1I If there is any malfunction: Refer to the applicable service information and verify whether or not there is a common connector between the following terminals: Evaporator temperature sensor terminal B-Front climate control unit terminal 1P Evaporator temperature sensor terminal A-Front climate control unit terminal 1I If there is a common connector: Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short or open circuit. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has a short or open circuit.
7	DETERMINE IF MALFUNCTION CAUSE IS INSTRUMENT CLUSTER OR OTHER Verify the display indication of A/C system while turning on and off the air conditioner using the switch on the control panel. Does the display indicate properly?	Yes	A/C switch malfunction, or front climate control unit can not determine the A/C request or transmit the A/C request signal. Replace the front climate control unit. (See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION .)
7		No	Instrument cluster does not receive the A/C request signal from front climate control unit or transmit it to PCM. Replace the instrument cluster. (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION .)
8	DETERMINE IF MALFUNCTION CAUSE IS A/C CONTROL SIGNAL OR MAGNETIC CLUTCH Start the engine and idle it. Access the PCM simulation item ACCS using the M-MDS. (See On-Board Diagnostic Test .) Turn the ACCS PID to ON from OFF using the M-MDS simulation function. Measure the voltage at the magnetic clutch terminal A (wiring harness-side). Is the voltage 10.5 V or more?	Yes	Go to the next step.
8		No	Go to Step 10.
9	INSPECT IF MALFUNCTION CAUSE IS MAGNETIC CLUTCH OR MAGNETIC CLUTCH GROUND CIRCUIT Switch the ignition off. Disconnect the magnetic clutch connector. Inspect for continuity between magnetic clutch terminal A (part-side) and body ground. Is there continuity?	Yes	Inspect the magnetic clutch. (See MAGNETIC CLUTCH INSPECTION .) Replace the magnetic clutch if necessary.
9		No	Inspect the A/C compressor. (poor contact to ground) If there is any malfunction: Repair or replace the malfunctioning part according to the inspection results. If there is no malfunction: Replace the A/C compressor. (internal circuit open)
10	INSPECT A/C RELAY Switch the ignition off. Remove the A/C relay. Inspect the A/C relay. (See RELAY INSPECTION .) Is there any malfunction?	Yes	Replace the A/C relay.
10		No	Go to the next step.
11	INSPECT A/C RELAY CONTROL CIRCUIT FOR OPEN CIRCUIT A/C relay is removed. Disconnect the PCM connector. Inspect for continuity between A/C relay terminal E (wiring harness-side) and PCM terminal 2BB (wiring harness-side). Is there continuity?	Yes	Inspect for continuity between the following: Front body control module (FBCM) terminal 1C-A/C relay terminal A Battery positive terminal-A/C relay terminal D A/C relay terminal C-Magnetic clutch terminal A Refer to the applicable service information and verify whether or not there is a common connector between the following terminals: Front body control module (FBCM) terminal 1C-A/C relay terminal A Battery positive terminal-A/C relay terminal D A/C relay terminal C-Magnetic clutch terminal A If there is a common connector: Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has an open circuit.
11		No	Refer to the applicable service information and verify whether or not there is a common connector between A/C relay terminal E and PCM terminal 2BB. If there is a common connector: Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has an open circuit.
12	Verify the test results. If normal, return to the diagnostic index to service any additional symptoms. (See Symptom Diagnostic Index .) If a malfunction remains, inspect the related Service Information and perform the repair or diagnosis. If the vehicle is repaired, troubleshooting is completed. If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM Removal/Installation .)