A/C Control Signal (ACCS) Malfunction

DTC DETECTION CONDITION POSSIBLE COUSES CHART

DTC P1464	A/C CONTROL SIGNAL (ACCS) MALFUNCTION
DETECTION CONDITION	P1464 indicates that the ACCS input to the PCM was high during the self-test.
POSSIBLE CAUSES	A/C was on during self-test. A/C clutch PWR circuit short to power. Short to power on ACCS circuit. Damaged A/C Demand switch. Damaged A/C clutch relay. Damaged PCM.
HINT	ACCS Description When the A/C cycling switch opens, the PCM will turn off the A/C clutch. The A/C cycling switch circuit to the PCM provides a voltage signal which indicates when the A/C is requested. When the A/C demand switch is turned on, and both the A/C cycling switch and the duel pressure contacts of the A/C duel pressure switch are closed, voltage is supplied to the ACCS circuit at the PCM. If the ACCS signal is not received by the PCM, the PCM will not allow the A/C to operate.
Courtesy of MAZDA MOTORS CORP.
Courtesy of MAZDA MOTORS CORP.

DTC DETECTION CONDITION POSSIBLE COUSES CHART

STEP	INSPECTION		ACTION
1	Was PCM Quick Test carried out?	Yes	GO to the next step.
1	Was PCM Quick Test carried out?	No	CARRY OUT the PCM Quick Test. See PCM QUICK TEST .
2	DTC P1464: CHECK ACCS PID NOTE: Verify that A/C and defrost were OFF during self-test. If A/C or defrost were on, turn off and rerun self-test. Key ON, engine OFF (KOEO). A/C and defrost off. Using IDS or equivalent tester, select Diagnostic Data Link. Select PCM. Select PID/Data Monitor and Record. Access ACCS PID. Is ACCS PID on?	Yes	GO to the next step.
2		No	The ACCS PID indicates that the ACCS input to the PCM is low. VERIFY test results. With A/C and defrost OFF, RERUN self-test where P1464 was received. GO to step 7.
3	ACCS PID ON: DISCONNECT A/C CYCLING SWITCH AND CHECK IF ACCS PID TURNS OFF Key OFF. Disconnect A/C cycling switch. Key ON, engine OFF (KOEO). Access ACCS PID from PID/Data Monitor and Record. Is ACCS PID off?	Yes	VERIFY operation of A/C Demand Switch. See SYMPTOM TROUBLESHOOTING CHART - CLIMATE CONTROL . If OK, REPAIR short to power in A/C demand circuit (V) to A/C cycling switch. GO to step 7.
3		No	GO to the next step.
4	CHECK POWER TO A/C CLUTCH CIRCUIT FOR SHORT TO POWER Key OFF. Disconnect A/C clutch relay. Key ON, engine OFF (KOEO). Measure voltage between A/C clutch power circuit (GY/W) in harness connector and chassis ground. Key OFF. Was voltage less than 1.0 V?	Yes	GO to the next step.
4		No	REPAIR circuit short to power. GO to step 7.
5	CHECK ACCS CIRCUIT FOR SHORT TO POWER Disconnect PCM. Key ON, engine OFF (KOEO). Measure voltage between PCM pin C15 (ACCS) and PCM pin C49 (PWR GND). Key OFF. Was voltage less than 1.0 V?	Yes	GO to the next step.
5		No	REPAIR ACCS circuit to power. GO to step 7.
6	CHECK ACCS CIRCUIT VOLTAGE TO PCM WITH A/C CLUTCH RELAY CONNECTED Reconnect A/C clutch relay. Key ON, engine OFF (KOEO). Measure voltage between PCM pin C15 (ACCS) and PCM pin C49 (PWR GND). Key OFF. Was voltage less than 1.0 V?	Yes	INSTALL a new PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL/INSTALLATION - 2.5L or POWERTRAIN CONTROL MODULE (PCM) REMOVAL/INSTALLATION - 3.0L . GO to the next step.
6		No	REPLACE A/C clutch relay. GO to the next step.
7	VERIFY TROUBLESHOOTING OF DTCs COMPLETED Make sure to reconnect all disconnected connectors. Clear DTCs from PCM memory using IDS or equivalent tester generic OBD II function. Carry out PCM Quick Test. See PCM QUICK TEST . Is same DTC present?	Yes	INSTALL a new PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL/INSTALLATION - 2.5L or POWERTRAIN CONTROL MODULE (PCM) REMOVAL/INSTALLATION - 3.0L . REPEAT the PCM Quick Test. See PCM QUICK TEST .
7		No	If any other DTC is present, go to applicable DTC inspection. If no DTC is present, troubleshooting complete.