P0530 – AC refrigerant pressure sensor -circuit malfunction

By Reinier (Contact Me)
Last Updated 2017-08-03
Automobile Repair Shop Owner

Table of Contents

1. What Does Code P0530 Mean?
2. What are the common causes of code P0530 ?
3. What are the symptoms of code P0530 ?
4. How do you troubleshoot code P0530 ?
5. Codes Related to P0530
6. Get Help with P0530

What Does Code P0530 Mean?

SPECIAL NOTES: Non-professional mechanics should note that apart from a few basic troubleshooting and repair steps, code P0530 – “AC refrigerant pressure sensor -circuit malfunction” is generally not repairable on a DIY basis.

By law, only suitably qualified and federally-mandated personnel are allowed to work on automotive HVAC systems. Thus, since replacement of pressure sensors on an A/C system necessarily involves some refrigerant escaping from the system (and then recharging of the system) this procedure must be left to suitably qualified personnel who have access to the legally required equipment and skills.  END OF SPECIAL NOTES.  

OBD II fault code P0530 is a generic code that is defined as   “AC refrigerant pressure sensor -circuit malfunction”, and is set when the BCM (Body Control Module), ECC (Electronic Climate Control Module), or in some cases, the PCM (Powertrain Control Module) detects an electrical malfunction in the control circuit of one or more pressure sensors in the A/C system.

NOTE: While code P0530 can sometimes indicate problems with the refrigerant pressure, it is far more common for this fault to indicate a purely electrical malfunction in a pressure sensors’ control circuit, of which the pressure sensor forms a part. Also note that some A/C systems can have as many as four pressure sensors to ensure proper operation of the system.

To operate efficiently, an A/C system needs to be charged with a precisely weighed amount of refrigerant, which not only provides the mechanism that produces cold air, but also serves to distribute a quantity of lubricating oil throughout the system. However, in a fully functional A/C system, different parts of the system are always operating at different pressures, and the purpose of the pressure sensors is to provide the relevant control modules with input data on the pressures that obtain in different parts of the system at all times.

Additionally, the pressure sensors in an A/C system also serve as safety devices. For instance, if the system pressure is low, i.e., there is insufficient refrigerant in the system for whatever reason, the low-pressure reading will cause the relevant control module to deactivate the compressor clutch. In practice, this means that the entire A/C system is deactivated, and will remain deactivated until the problem is resolved. The relevant control module will also set code P0530, and may illuminate a warning light.

The image below shows a typical A/C system pressure switch, such as might be found on almost any modern application today.

What are the common causes of code P0530 ?

Some common causes of code P0530 could include the following-

• Damaged, burnt, shorted, disconnected, or corroded wiring and or connectors
• Defective pressure sensor(s)
• Low A/C system (refrigerant) pressure
• Excessive A/C system (refrigerant) pressure
• Failed or failing ECC (Electronic Climate Control) or BCM (Body Control Module). Note that is a rare event, and the fault must be sought elsewhere before any control module is replaced

What are the symptoms of code P0530 ?

Some common symptoms of code P0530 could include the following-

• Stored trouble code and possibly an illuminated warning light
• A/C system will almost certainly fail to activate
• In cases where the A/C system does activate, it may work erratically, or not cool properly

How do you troubleshoot code P0530 ?

Step 1

Record all fault codes present, as well as all available freeze frame data. This information can be of use should an intermittent fault be diagnosed later on.

Step 2

Refer to the manual to identify and locate ALL pressure switches fitted to the A/C system. Note though that on some applications, some pressure switches are extremely challenging to access, and it may be necessary to remove parts of the dashboard, or unrelated components in the engine compartment. Be sure to follow the directions in the manual exactly to avoid damaging wiring or other sensitive parts and components.

Step 3

Once all pressure switches are accessible, determine the color coding and function of each wire in each connector. In most cases, each pressure switch connector will have three wires; one ground wire, one wire will be a signal wire, and the last wire will carry a 5V reference voltage.

Step 4

Inspect all wires as far as possible; check for damaged, burnt, shorted, disconnected, and corroded wiring and or connectors. Make repairs or replace wiring as required.

NOTE: Damaged wiring is a very common cause of code P0530, so pay particular attention to the condition of all wiring during this step.

Step 5

If no visible damage to wiring is found, perform reference voltage, continuity, and resistance checks on all associated wiring. Be sure however to disconnect all wiring from all relevant control modules to prevent damaging one or more controllers during resistance checks.

Compare all obtained readings with the values stated in the manual, and make repairs or replace wiring as required to ensure that all electrical value fall within the ranges specified by the manufacturer.

NOTE #1: Pressure sensors form part of their control circuits, and as such, they must be tested as well, but be sure to follow the testing procedure recommended in the manual exactly to avoid a misdiagnosis. Pay particular attention to the internal resistance of the sensors, since this value is a reasonably good indicator of their overall condition.

NOTE #2: Take note that any given A/C pressure sensors’ resistance and other electrical values/characteristics depend entirely on where in the system that sensor is fitted. It is therefore critically important to make sure that all obtained test readings for any pressure sensor are compared to the correct set of reference data in the manual- getting this step wrong will result in a misdiagnosis, and the almost certain unnecessary replacement of parts and components.

Step 6

Note that if a defective pressure sensor is identified, the sensor should NOT be removed and replaced on a DIY basis. Doing this could cause serious damage to the A/C system, but more importantly, discharging an A/C system into the atmosphere is illegal in all jurisdictions.

Therefore, refer the vehicle to the dealer or a specialist HVAC repairer for professional assistance with replacing defective sensors and components.

Codes Related to P0530

• P0531 – “A/C Refrigerant Pressure Sensor “A” Circuit Range/Performance”
• P0532 – “A/C Refrigerant Pressure Sensor “A” Circuit Low”
• P0533 – “A/C Refrigerant Pressure Sensor “A” Circuit High”

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