NO.23 A/C DOES NOT WORK SUFFICIENTLY [MZI-3.7]

id0103d2802900

23 | A/C DOES NOT WORK SUFFICIENTLY
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DESCRIPTION | • A/C compressor magnetic clutch does not engage when A/C is turned on.
POSSIBLE CAUSE | • PCM or climate control unit DTC is stored. • Refrigerant pressure sensor malfunction • Improper refrigerant charging amount • Seized A/C compressor • Front evaporator temperature sensor malfunction • Open or short circuit in wiring harness between front evaporator temperature sensor and front climate control unit • Instrument cluster malfunction (Does not receive A/C request signal from climate control unit or transmit it to PCM.) • Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal.) • Open or short circuit in wiring harness between front climate control unit terminal 2A and instrument cluster terminal 1C • A/C compressor malfunction • Open circuit in wiring harness between magnetic clutch terminal A and body ground • A/C relay malfunction • Open circuit in wiring harness between A/C relay and PCM • Open circuit in wiring harness between main relay No.1 and A/C relay • Open circuit in wiring harness between battery positive terminal and A/C relay • Open circuit in wiring harness between A/C relay and magnetic clutch

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | Retrieve the PCM and climate control unit DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) (See DIAGNOSTIC TROUBLE CODE NUMBER INSPECTION.) Are there any DTCs displayed? | Yes | Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7].) (See DIAGNOSTIC TROUBLE CODE NUMBER INSPECTION.)
No | Go to the next step.
2 | Access the PCM PID ACCS using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) Start the engine and idle it. Turn the PCM PID ACCS to ON from OFF using the M-MDS simulation function. Is the magnetic clutch engaged? | Yes | Go to the next step.
No | Go to Step 9.
3 | Measure the voltage at the PCM terminal 1M (wiring harness-side). Is the voltage normal? (See PCM INSPECTION [MZI-3.7].) | Yes | Go to Step 5.
No | Go to the next step.
4 | Inspect the refrigerant pressure sensor. (See REFRIGERANT PRESSURE SENSOR INSPECTION.) Is there any malfunction? | Yes | Replace the refrigerant pressure sensor. (See REFRIGERANT PRESSURE SENSOR REMOVAL/INSTALLATION.)
No | Inspect the following: • Refrigerant charging amount • A/C compressor for seizure Repair or replace the malfunctioning part according to the inspection results.
5 | Remove the front climate control unit. (See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.) Reconnect the front climate control unit connector. Measure the voltage at the front climate control unit terminal 2H (wiring harness-side). Is the voltage normal? (See FRONT CLIMATE CONTROL UNIT INSPECTION.) | Yes | Go to Step 7.
No | Go to the next step.
6 | Inspect the front evaporator temperature sensor. (See FRONT EVAPORATOR TEMPERATURE SENSOR INSPECTION.) Is there any malfunction? | Yes | Replace the front evaporator temperature sensor. (See FRONT EVAPORATOR TEMPERATURE SENSOR REMOVAL/INSTALLATION.)
No | Inspect for open or short circuit between front evaporator temperature sensor and front climate control unit. Repair or replace suspected wiring harness and connector.
7 | Remove the front climate control unit. (See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.) Reconnect the front climate control unit connector. Start the engine and idle it. Measure the voltage at the front climate control unit terminal 2A (wiring harness-side) while turning on and off the air conditioner by switching the control panel. Is the voltage change in specified according to air control panel switching? • Specification ― Turn on the A/C: Below 1.0 V ― Turn off the A/C: Approx. 5 V | Yes | Replace the instrument cluster. (Instrument cluster does not receive A/C request signal from climate control unit or transmit it to PCM.) (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)
No | Go to the next step.
8 | Inspect for open or short circuit between front climate control unit terminal 2A (wiring harness-side) and instrument cluster terminal 1C (wiring harness-side). Is there any malfunction? | Yes | Repair or replace suspected wiring harness and connector.
No | Replace the front climate control unit. (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal.) (See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)
9 | Start the engine and idle it. Turn the PCM PID ACCS to ON from OFF using the M-MDS simulation function. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) Measure the voltage at the magnetic clutch terminal A (wiring harness-side). Is the voltage specified? • Specification ― 10.5 V or more | Yes | Go to the next step.
No | Go to Step 11.
10 | Inspect for continuity between magnetic clutch terminal A (wiring harness-side) and body ground. Is there continuity? | Yes | Replace the A/C compressor. (See A/C COMPRESSOR REMOVAL/INSTALLATION.)
No | Repair or replace suspected wiring harness and connector.
11 | Inspect the A/C relay. (See RELAY INSPECTION.) Is there any malfunction? | Yes | Replace the A/C relay.
No | Go to the next step.
12 | Switch the ignition to off. Disconnect the A/C relay and PCM connectors. Inspect for continuity between the following (wiring harness-side): • A/C relay and PCM terminal 1W Is there continuity? | Yes | Inspect for open circuit between the following: • Main relay No.1 and A/C relay • Battery positive terminal and A/C relay • A/C relay and magnetic clutch Repair or replace suspected wiring harness and connector.
No | Repair or replace suspected wiring harness and connector.
13 | • Verify test results. ― If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].) ― If malfunction remains, inspect related Service Information and perform repair or diagnosis. • If vehicle is repaired, troubleshooting completed. • If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7].)