P0537 OBD-II Trouble Code: A/C Evaporator Temperature Sensor Circuit Low

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0537 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0537 code

P0537 is a diagnostic trouble code (DTC) for "A/C Evaporator Temperature Sensor Circuit Low". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0537 DIAGNOSTIC Get a fair and transparent estimate upfront

Check Engine Light

P0537 A/C evaporator temperature sensor circuit low definition

A P0537 code indicates that the Powertrain Control Module (PCM) has stored voltage readings from the A/C evaporator temperature sensor that are outside of normal parameters, triggering a trouble code.

What the P0537 code means

The temperature switch in an automotive A/C system is mounted in the evaporator core’s fins and is of a capillary design. When the evaporator core’s temperature drops, the capillary pressure in the switch drops, lowering circuit resistance and increasing the voltage input signal to the PCM. The PCM sees this as a change in temperature and cycles the compressor clutch on and off. A trouble code is registered when these voltage fluctuations are at odds with the reference limit. Usually three failure cycles are necessary before the PCM will store a code and illuminate the Malfunction Indicator Lamp (MIL).

What causes a P0537 code?

  • Failed evaporator temp sensor
  • Failed expansion valve, resulting in freeze up of evaporator core
  • Damaged or shorted wiring
  • Overcharged A/C system
  • Low refrigerant condition
  • Faulty climate control head unit

What are the symptoms of a P0537 code?

  • Inoperative A/C system
  • Stored code, illuminated MIL
  • Air conditioning “ON” indicator lamp (on A/C switch) flashes repeatedly
  • Freeze up of evaporator case, with condensate dripping onto floor

How does a mechanic diagnose a P0537 code?

An OBD-II code reader/scanner, digital volt/ohmmeter and a set of A/C gauges or A/C recycling machine with built-in gauges will be necessary for this diagnosis and repair.

  • Begin by visually inspecting all wiring and connectors. Repair/replace any damaged, disconnected, corroded or shorted wiring, connectors and parts as needed. Retest the system.

  • If all wiring, connectors, parts and fuses appear to be in good condition, connect the scanner/code reader to the diagnostic port. Record all stored codes and freeze frame data.

  • Test drive the vehicle to see if the code returns. If not, the problem may be an intermittent condition. Intermittent conditions can be difficult to diagnose correctly and may need to be allowed to worsen and return before a proper diagnosis can be made.

  • Connect A/C gauges to the proper fittings, start the engine and turn the blower on its highest setting, with A/C on Max. Observe gauge readings and compare to factory specs, making adjustments in refrigerant level as needed. Turn the blower speed to Low and observe gauges for pressure readings.

  • If system’s low-side pressure falls too much – below 25 PSI or so – it can cause a freezeup of the evaporator and a trouble code. If this occurs, the expansion valve could be at fault.

  • If the A/C system operates normally, perform a resistance test on the evaporator temperature sensor’s electrical connector (unplug the sensor first)

  • Compare your numbers to factory specs, replace sensor if needed.

  • If evaporator temperature sensor seems to be within operating norms, disconnect the PCM electrical connector and electrical connector for the climate control head unit. Do a resistance/continuity test on the evaporator temperature sensor circuit. Repair/replace any shorted or open wiring as needed. If the evaporator temperature sensor and circuits test as good, suspect the head unit itself or the A/C compressor switch.

  • Test unit, compare to factory specs and replace components as needed.

Common mistakes while diagnosing P0537 code

Often, with a P0537 code, technicians or owners overfill their vehicles’ systems with refrigerant, resulting in problems. It’s important to know that it’s absolutely necessary to add refrigerant before moving forward, and only qualified personnel with the right tools/equipment should attempt this service. Single hose charging kits, with no gauge or an inadequate gauge, often lead to a catastrophic failure.

How serious is a P0537 code?

Operating the A/C system with a P0537 code can lead to failure of components and further problems.

What repairs can fix a P0537 code?

Addition comments for consideration for P0537 code

While the lines, O-rings and gaskets of an A/C system are porous and even a newer vehicle can lose 5 percent of its refrigerant over a year’s time, it’s important to not just add refrigerant if a P0537 code is registered. Make sure you’ve found the root cause of the P0537 code before going any further.

Need help with a P0537 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

trouble codes
Check Engine Light
P0537

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0537 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

3,815

Rating Summary
3,485
164
43
24
99
3,485
164
43
24
99

William

17 years of experience
120 reviews
William
17 years of experience
William was fantastic. He showed up within the time frame expected. Told me exactly what the issue was. What was needed to fix it. I booked the appointment directly from the quote sent. Turned out to be less than what he actually quoted. Use William any time you need a good reliable mechanic.
2012 TOYOTA YARIS - CHECK ENGINE LIGHT IS ON - FORT MYERS, FLORIDA

Theodore

13 years of experience
814 reviews
Theodore
13 years of experience
An outstanding professional who provides a 360 view and transparency in everything he does. I had a really hard engine problem to repair (Lean System). Theodore tried A then B then C....till he identified what caused the misfire of the engine. Based on my previous horrible experiences with some local car repair shops, i can tell you for a fact that he saved me many 00's, if not 000's, of dollars. Highly recommended, will call him again for some other minor issues with a second car we have.
2006 FORD ESCAPE - CHECK ENGINE LIGHT IS ON - SAMMAMISH, WASHINGTON

Theodore

13 years of experience
814 reviews
Theodore
13 years of experience
Theodore was very professional and responsive.
2004 HYUNDAI ELANTRA - CHECK ENGINE LIGHT IS ON - EVERETT, WASHINGTON

Chris

13 years of experience
397 reviews
Chris
13 years of experience
Chris has been a great help. He gave me an honest opinion and helped me with a variety of options. He understands when things may be too expensive, and was upfront about it. Definitely customer oriented! Thank you Chriss!
2005 SCION XB - CHECK ENGINE LIGHT IS ON - SAN FRANCISCO, CALIFORNIA

More related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...
P0608 OBD-II Trouble Code: Control Module VSS Output "A" Malfunction
P0608 means there is an malfunction in the vehicle speed sensor A control module often due too faulty speed sensor or shorted electrical wiring.

Related questions

Q: Code p0101

The P0101 trouble code may keep returning if the engine computer does not see the MAF sensor input within a specified range when it is testing the MAF input. The input can be wrong if the engine has another problem...

Q: my car make rattling noise ,feel like it stops and goes,while driving, and now displays "check engine"

Inasmuch as the check engine light has illuminated, diagnostic trouble codes have been stored in your car's engine computer (PCM) and those codes, once downloaded, will probably reveal at least the general cause of the problem you are having. If...

Q: I got a p 507 code

That's a good question. P507 is your idle speed control. There are a few issues you may want to look into. The throttle valve may be sticking, bad throttle motor, ECM, or a wiring problem. I would start by checking...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com