Test Procedure

DS1 CHECK FOR DTCS

Are DTCs P0532, P0533, P1461, P1462, or P1463 present?

Yes	No
For DTC P0533, P1461, GO to DS2. For DTC P0532, P1462, GO to DS8. For DTC P1463, GO to DS17.	For symptoms without DTCs, GO to DS19. For all others, GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .

DS2 DTC P0533, P1461: CHECK THE ACP V PID

Key ON, engine OFF.
Access the PCM and monitor the ACP V PID.

Is the voltage less than 4.9 V?

Yes	No
The ACP voltage is now below maximum. To determine if an intermittent condition exists, GO to DS16.	GO to DS3.

DS3 CHECK THE VOLTAGE BETWEEN THE VREF AND SIGRTN CIRCUITS AT THE ACP SENSOR VEHICLE HARNESS CONNECTOR

ACP Sensor connector disconnected.
Key ON, engine OFF.

Measure the voltage between:

( + ) ACP Sensor Connector, Harness Side	( - ) ACP Sensor Connector, Harness Side
VREF - Pin 2	SIGRTN - Pin 1

Is the voltage between 4 - 6 V?

Yes	No
GO to DS4.	GO to Pinpoint Test C .

DS4 CHECK THE ACP CIRCUIT FOR A SHORT TO VREF

Key in OFF position.
PCM connector disconnected.

Measure the resistance between:

( + ) ACP Sensor Connector, Harness Side	( - ) ACP Sensor Connector, Harness Side
ACP - Pin 3	VREF - Pin 2

Is the resistance greater than 10K ohms?

Yes	No
GO to DS5.	REPAIR the short circuit to VREF. CLEAR the DTCs. REPEAT the self-test.

DS5 CHECK THE ACP CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS

Key ON, engine OFF.

Measure the voltage between:

( + ) ACP Sensor Connector, Harness Side	( - )
ACP - Pin 3	Ground

Is the voltage less than 1 V?

Yes	No
GO to DS6.	REPAIR the short circuit to PWR. CLEAR the DTCs. REPEAT the self-test.

DS6 CHECK FOR AN OPEN ACP CIRCUIT IN THE HARNESS

Key in OFF position.

Measure the resistance between:

( + ) ACP Sensor Connector, Harness Side	( - ) PCM Connector, Harness Side
ACP - Pin 3	ACP

Is the resistance less than 5 ohms?

Yes	No
GO to DS7.	REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.

DS7 CHECK THE PCM

NOTE: If a diagnostic tool communication concern exists, follow the NO answer.

PCM connector connected.

Connect a 5 amp fused jumper wire between the following:

Point A ACP Sensor Connector, Harness Side	Point B ACP Sensor Connector, Harness Side
ACP - Pin 3	SIGRTN - Pin 1

Key ON, engine OFF.
Access the PCM and monitor the ACP V PID.

Is the voltage less than 4.9 V?

Yes	No
INSTALL a new ACP sensor. REFER to the appropriate CLIMATE CONTROL article . CLEAR the DTCs. REPEAT the self-test.	GO to DS23.

DS8 DTC P0532, P1462: CHECK THE ACP V PID

Key ON, engine OFF.
Access the PCM and monitor the ACP V PID.

Is the voltage greater than 0.15 V?

Yes	No
The ACP voltage is now above the minimum. To determine if an intermittent condition exists, GO to DS16.	GO to DS9.

DS9 CHECK THE VOLTAGE BETWEEN THE VREF AND SIGRTN CIRCUITS AT THE ACP SENSOR VEHICLE HARNESS CONNECTOR

ACP Sensor connector disconnected.
Key ON, engine OFF.

Measure the voltage between:

( + ) ACP Sensor Connector, Harness Side	( - ) ACP Sensor Connector, Harness Side
VREF - Pin 2	SIGRTN - Pin 1

Is the voltage between 4 - 6 V?

Yes	No
GO to DS10.	GO to Pinpoint Test C .

DS10 SIMULATE AN OPPOSITE SIGNAL TO THE PCM

Key in OFF position.

Connect a 5 amp fused jumper wire between the following:

Point A ACP Sensor Connector, Harness Side	Point B ACP Sensor Connector, Harness Side
VREF - Pin 2	ACP - Pin 3

Key ON, engine OFF.
Access the PCM and monitor the ACP V PID.

Is the voltage greater than 4 V?

Yes	No
INSTALL a new ACP sensor. REFER to the appropriate CLIMATE CONTROL article . CLEAR the DTCs. REPEAT the self-test.	GO to DS11.

DS11 CHECK THE ACP CIRCUIT FOR A SHORT TO GND

Key in OFF position.
PCM connector disconnected.

Measure the resistance between:

( + ) ACP Sensor Connector, Harness Side	( - )
ACP - Pin 3	Ground

Is the resistance greater than 10K ohms?

Yes	No
GO to DS12.	REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test.

DS12 CHECK THE ACP CIRCUIT FOR A SHORT TO SIGRTN

Measure the resistance between:

( + ) ACP Sensor Connector, Harness Side	( - ) ACP Sensor Connector, Harness Side
ACP - Pin 3	SIGRTN - Pin 1

Is the resistance greater than 10K ohms?

Yes	No
GO to DS13.	REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test.

DS13 CHECK THE ACP CIRCUIT(S) FOR AN OPEN IN THE HARNESS

Measure the resistance between:

( + ) ACP Sensor Connector, Harness Side	( - ) PCM Connector, Harness Side
ACP - Pin 3	ACP

Is the resistance less than 5 ohms?

Yes	No
GO to DS14.	REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.

DS14 CHECK FOR THE A/C CLUTCH TO ENGAGE

PCM connector connected.
ACP Sensor connector connected.
Key ON, engine running.
While listening for the A/C clutch to engage, turn the A/C on. Repeat if necessary.

Does the A/C engage when the A/C is turned on?

Yes	No
GO to DS23.	GO to DS15.

DS15 VERIFY THE A/C SYSTEM FUNCTION, INCLUDING THE REFRIGERANT CHARGE

Restore the vehicle.
Verify the A/C system function, including the refrigerant charge. Refer to the appropriate CLIMATE CONTROL SYSTEM GENERAL INFORMATION article .

Does the A/C system have the correct refrigerant charge and if so does the A/C system function correctly?

Yes	No
GO to DS23.	REFER to the appropriate CLIMATE CONTROL SYSTEM GENERAL INFORMATION article to continue to diagnose the A/C system pressure.

DS16 CHECK THE ACP CIRCUIT FOR AN INTERMITTENT CONCERN

NOTE: A concern is indicated by a sudden change in voltage.

Key ON, engine OFF.
Access the PCM and monitor the ACP V PID.
Observe the ACP V PID for an indication of a concern while carrying out the following:
- Shake, wiggle, and bend the ACP, SIGRTN, and VREF wires between the ACP sensor and PCM
- Lightly tap on the ACP sensor to simulate road shock

Is a concern present?

Yes	No
ISOLATE the concern and REPAIR as necessary. CLEAR the DTCs. REPEAT the selftest.	Unable to duplicate or identify the concern at this time. GO to Pinpoint Test Z .

DS17 DTC P1463: VERIFY THE A/C CLUTCH CAN DISENGAGE

Turn the A/C and defroster OFF.
Key ON, engine running.
Verify the A/C clutch can disengage.

Is the A/C clutch disengaged?

Yes	No
GO to DS18.	REFER to the appropriate CLIMATE CONTROL SYSTEM GENERAL INFORMATION article to continue diagnosis for the lack of the A/C clutch disengagement.

DS18 CHECK FOR VOLTAGE AND GROUND TO THE A/C CLUTCH USING A NONPOWERED TEST LAMP

NOTE: If voltage and ground to the A/C clutch have already been checked or the A/C clutch can be heard clicking on when the A/C is turned on, go to the question at the end of this test step.

Key in OFF position.
A/CCS Switch connector disconnected.
Connect a jumper wire in the A/C low pressure cycling switch harness connector to complete the circuit.
A/CC Assembly connector disconnected.
Connect a non-powered test lamp between the voltage pin and ground pin at the A/C clutch harness connector.
Key ON, engine running.
Turn the A/C on, and wait 15 seconds.
Monitor the test lamp.
Connect the A/C clutch and A/C cycling switch when done testing.

Does the lamp illuminate, or can the A/C clutch be heard clicking on?

Yes	No
GO to DS19.	REFER to the appropriate CLIMATE CONTROL SYSTEM GENERAL INFORMATION article to diagnose the circuits to the A/C Clutch.

DS19 DETERMINE IF A SUFFICIENT A/C PRESSURE CHANGE CAN BE DETECTED BY THE ACP V PID

Key ON, engine running.
Turn the A/C and defroster OFF.
Access the PCM and monitor the ACP V PID.
Turn the A/C and defroster OFF.
Five seconds after A/C clutch engagement, note the voltage. If the clutch does not engage, follow the NO answer instructions.

Does the PCM-ACP V PID change more than 0.3 volt within 5 seconds of clutch engagement?

Yes	No
The ACP sensor and the PCM can detect a sufficient change in the A/C pressure. For symptom without DTC P1463, REFER to SYMPTOM CHARTS . For all others, REFER to the appropriate CLIMATE CONTROL SYSTEM GENERAL INFORMATION article to further diagnose the circuits to the A/C pressure system.	GO to DS20.

DS20 CHECK THE A/C SYSTEM PRESSURE AND PRESSURE CHANGE

Key in OFF position.
Install an A/C system manifold gauge set and check the A/C system high pressure reading.
Turn the A/C and defroster OFF.
Key ON, engine running.
Note the A/C high pressure reading.
While monitoring the A/C system high pressure reading, turn the A/C on. Five seconds after clutch engagement, note the pressure (the pressure should increase).
A/C and defroster OFF.

Does the A/C high pressure reading change more than 207 kPa (30 psi) within 5 seconds of clutch engagement?

Yes	No
GO to DS21.	REFER to the appropriate CLIMATE CONTROL SYSTEM GENERAL INFORMATION article to diagnose the A/C pressure system.

DS21 CHECK THE VOLTAGE BETWEEN THE VREF AND SIGRTN CIRCUITS AT THE ACP SENSOR VEHICLE HARNESS CONNECTOR

Key in OFF position.
ACP Sensor connector disconnected.
Key ON, engine OFF.

Measure the voltage between:

( + ) ACP Sensor Connector, Harness Side	( - ) ACP Sensor Connector, Harness Side
VREF - Pin 2	SIGRTN - Pin 1

Is the voltage between 4 - 6 V?

Yes	No
GO to DS22.	GO to Pinpoint Test C .

DS22 CHECK THE ACP CIRCUIT(S) FOR AN OPEN IN THE HARNESS

PCM connector disconnected.

Measure the resistance between:

( + ) ACP Sensor Connector, Harness Side	( - ) PCM Connector, Harness Side
ACP - Pin 3	ACP

Is the resistance less than 5 ohms?

Yes	No
INSTALL a new ACP sensor. REFER to the appropriate CLIMATE CONTROL article . CLEAR the DTCs. REPEAT the self-test.	REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.

DS23 CHECK FOR CORRECT PCM OPERATION

Disconnect all the PCM connectors.
Visually inspect for:
- pushed out pins
- corrosion
Connect all the PCM connectors and make sure they seat correctly.
Carry out the PCM self-test and verify the concern is still present.

Is the concern still present?

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.