Fix P0532: Mechanic’s solutions that WORKED

The P0532: A/C Refrigerant Pressure Sensor Circuit Low Input code indicates an issue with the A/C refrigerant pressure sensor circuit, specifically signaling a low input. This sensor is crucial for monitoring the refrigerant pressure in the air conditioning system, which is essential for efficient cooling. A low input signal can mean the sensor is not functioning properly, or there may be an underlying issue in the A/C system.

P0532 quick overview

Meaning	P0532: A/C Refrigerant Pressure Sensor Circuit Low Input
Is it serious?	This code can be serious as it may affect the vehicle’s air conditioning system, potentially leading to uncomfortable driving conditions or further system damage.
Possible causes	– Faulty A/C refrigerant pressure sensor – Low refrigerant levels in the A/C system – Electrical issues in the A/C pressure sensor circuit – Damaged or corroded wiring and connectors – Malfunctioning climate control system
How to diagnose?	Inspect A/C Pressure Sensor: Check the A/C refrigerant pressure sensor for any signs of damage or malfunction. Check Refrigerant Levels: Ensure the A/C system has the correct amount of refrigerant. Examine Electrical Connections: Look at the wiring and connectors for any signs of damage, corrosion, or loose connections. Replace Sensor with OEM Part: Consider using an Original Equipment Manufacturer part for a replacement to ensure compatibility. Test the 5V Reference Circuit: Verify the 5V reference voltage in the A/C pressure sensor circuit. Monitor Related Sensors: Check other sensors on the same circuit, like oil pressure or MAP sensors. Consider ECM Evaluation: If other steps don’t resolve the issue, assess the Engine Control Module for potential faults.

How to fix P0532 – learn from mechanics

I looked into P0532 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Chevrolet

Vehicle Information: 2006 Chevrolet Aveo LT 1.6L

Issue + Repair History:

• Vehicle had no power with AC on.
• Scanned to find P0302 cylinder 2 misfire.
• Repairs included plugs, wires, timing belt, water pump, and coolant flush.
• After repairs, AC refused to work.
• Additional code P0532 found in the system.
• AC system properly charged but inoperative post-repair.

Other Test Results:

• AC high pressure switch – 5.0 ref 2.43 back to PCM (compressor off), reading -17 psi.

Suggestions to Fix Issue:

• Check for any disconnected pressure switch.
• Perform a battery disconnect for system reset.
• Clear any codes and reset KAM (Keep Alive Memory).
• Check power to the compressor clutch.
• Consider the possibility of freon leakage during repair.
• Replace the thermostat.
• Check AC compressor grounds and service AC if needed.
• Test AC clutch engagement with a scan tool or bypass relay.

Final Fix:

• The issue was identified as the PCM receiving false information, leading to the AC system shutdown.
• It was determined that the pressure switch was faulty.
• After testing a second switch, PCM readings normalized, indicating the pressure switch was the cause.

Case #2: Chevrolet

Vehicle Information: 2007 Chevrolet Tahoe LT 5.3L

Issue + Repair History:

• Truck had codes P0641, P0606, P0532, P0107.
• Issue occurred mainly when idling in park.
• Replaced ECM, but the problem persisted.
• Voltage in reference 1 circuit dropped to 2.2 volts in the freeze frame.

Computer Codes & Descriptions:

• P0641 – 5v ref. 1 ckt.
• P0606 – Control module internal performance
• P0532 – A/C reference pressure sensor circuit low volts
• P0107 – MAP sensor circuit low volt.

Suggestions to Fix Issue:

• Check for rodent damage or wiring issues due to a collision.
• Inspect wiring harness near the front driveshaft for shorts.
• Consider a faulty MAF or MAP sensor.
• Focus on the A/C pressure sensor as a possible cause.
• Check engine ground at the rear of the intake manifold.
• Unplug the radiator fans, clear codes, and retry.
• Examine A/C high pressure transducer and pigtail connector.

Final Fix:

• The problem was a short in the A/C system wiring, affecting signal to other modules.
• Specifically, the wire going to the A/C pressure sensor on the high side was at fault.
• Repairing the short in the A/C system wiring resolved the issue.

Case #3: Ford

Vehicle Information: 2016 Ford Flex Limited 3.5L

Issue + Repair History:

• A/C compressor not engaging; no power to the compressor.
• Code P06A0 – Variable A/C Compressor Control Circuit.
• PCM not sending a ground to switch the A/C compressor relay.
• Compressor works when power is added manually.
• Changed the pressure transducer due to code P0532.

Computer Codes & Descriptions:

• P06A0 – Variable A/C Compressor Control Circuit
• P0532 – A/C Pressure Sensor Circuit Low

Suggestions to Fix Issue:

• Check evaporator temperature sensor readings.
• Ensure no engine running issues that inhibit A/C operation.
• Verify if A/C is inhibited by a PCM code or other issue.
• Check for an open in the solenoid circuit.
• Inspect 15A fuse 70 in the battery junction box for issues.
• Confirm battery voltage at C175B pin 2 and 15A fuse 70.

Final Fix:

• Cleared all codes from every module and performed a hard reset.
• A/C compressor started working after the reset.
• Vehicle has been functioning properly for 2 weeks since the fix.

Case #4: Dodge

Vehicle Information: 2006 Dodge Ram 3500 SLT 5.9L

Issue + Repair History:

• Vehicle initially brought in for a melted down A/C clutch.
• After replacing the compressor and related parts, noticed that A/C clutch would not disengage, and trouble codes P0532 and P0483 were present.
• Additionally, the radio intermittently shut down, and brake lights were not working.
• Customer had the TIPM (Totally Integrated Power Module) replaced at the dealer recently.

Computer Codes & Descriptions:

• P0532 – A/C Reference Pressure Sensor Circuit Low Voltage
• P0483 – Fan Speed

Suggestions to Fix Issue:

• Initially, front control module replacement was suggested.
• Later clarified that the vehicle uses a TIPM, not a front control module.
• The TIPM controls the brake lights through a high side driver.

Final Fix:

• The vehicle was taken back to the dealer for warranty service on the TIPM.
• Dealer performed an update flash on the radio and replaced all taillight bulbs including the third brake lamp.
• Post-update, all issues including the A/C and brake lights were resolved.
• It was suggested that the TIPM might have been reprogrammed or fixed during the update.

Case #5: Cadillac

Vehicle Information: 2007 Cadillac Escalade 6.2L

Issue + Repair History:

• Vehicle had a 5v reference problem; only 2.2v at the MAP sensor.
• Unplugging the oil pressure sender initially restored the 5v reference.
• After replacing the sender, the issue recurred with voltage dropping to 2.2v.
• Considered a possible ECM issue due to consistent voltage drop.

Computer Codes & Descriptions:

• P0641 – 5v ref 1 circuit
• P0532 – A/C pressure sensor

Suggestions to Fix Issue:

• Try an OEM sending unit.
• Check fuel tank pressure sensor and A/C pressure transducer.
• Test evap solenoid and tank pressure sensor.
• Consider swapping A/C and fuel tank pressure sensors.
• Check for potential wiring issues with the sensor.
• Monitor PCM powers and grounds during the occurrence.

Final Fix:

• Replaced the oil pressure sender with an OEM part.
• The new OEM sender resolved the 5v circuit issue.
• A/C showed proper pressure and functioned correctly after the replacement.

Advice	Brief Description of Diagnostic Step
Check A/C Pressure Sensor	Inspect the A/C pressure sensor for faults or damage.
Inspect Wiring to A/C Pressure Sensor	Examine the wiring and connectors to the A/C pressure sensor for any damages or disconnections.
Replace A/C Pressure Sensor with OEM Part	Use an Original Equipment Manufacturer (OEM) part for replacement to ensure compatibility and reliability.
Test the 5V Reference Circuit	Verify the 5V reference voltage to the A/C pressure sensor and other related components.
Monitor Related Sensors	Check other sensors on the same circuit as the A/C pressure sensor, such as oil pressure sender or MAP sensor, for any issues that might affect the circuit.
Consider Potential ECM Issues	If the above steps don’t resolve the issue, evaluate the Engine Control Module (ECM) for faults.