P0543 OBD-II Trouble Code: Intake Air Heater "A" Circuit Open

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0543 code

P0543 is a diagnostic trouble code (DTC) for "Intake Air Heater "A" Circuit Open". 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. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 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$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0543 DIAGNOSTIC Get a fair and transparent estimate upfront

P0543 code definition

Detecting the P0543 code indicates that the PCM is reading an abnormal amount of input voltage from the intake air heater circuit.

What the P0543 code means

The engine control module, or ECM, uses an intake air heater that warms incoming air in order to achieve proper cylinder combustion. The ECM detects the voltage on the intake air heater circuits in order to determine that the heater is performing correctly. If the voltage is too high, the ECM assumes that the heater is in the open position when it isn’t meant to be, and will alert the PCM to store the P0543 code.

What causes the P0543 code?

The most common underlying issue for the P0543 code is a faulty intake air heater relay.

Other causes may include:

What are the symptoms of the P0543 code?

In most cases, the only symptoms will be the P0543 code stored in the PCM, and the illumination of the Check Engine lamp.

How does a mechanic diagnose the P0543 code?

After an OBD-II scanner detects the P0543 code, the first diagnostic step taken should be a visual inspection of all the wiring, connectors, and other electrical components. Any damaged elements should be replaced, reconnected, or repaired as necessary. Once this procedure is complete, the mechanic should then clear the code and test the system. If the code returns, they have successfully diagnosed an issue with the intake air heater and/or its circuit.

Common mistakes when diagnosing the P0543 code

In many cases, technicians or vehicle owners replace dirty air filters, or remove the air cleaner box for repairs, during a tune up, and do not reconnect the intake air temperature sensor correctly. It is common for some mechanics to begin replacing the intake air heater relay or other parts, before checking if a bad connection is the underlying issue.

How serious is the P0543 code?

If the P0543 code is being detected, the issue needs to be addressed right away. The vehicle’s ability to create the proper environment for cylinder combustion is vital to the overall operation, making this a very serious malfunction. Even though no symptoms may be present, it is important to have this repair performed right away when detected.

What repairs can fix the P0543 code?

There are many ways that a technician can address a P0543 code detection. They include:

It is important that after each repair, the mechanic clear the code from the PCM and preform a system test. If the code returns during the test, the previous repairs did not address the issue, and the mechanic must continue with diagnostics and repair. This process helps mechanics to pinpoint exactly what caused the issue in the first place, which can make future repairs much easier should the issue arise again.

Need help with a P0543 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
P0543
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0543 code.

SCHEDULE P0543 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,170

Rating Summary
4,765
197
50
27
131
4,765
197
50
27
131

Fred

16 years of experience
364 reviews
Fred
16 years of experience
Mercedes-Benz E500 - Check Engine Light is on - Conroe, Texas
Fred was very friendly and thorough to get to the root of the issue. Even when he could not find a fault to why my engine light was on, he went above and beyond to make absolutely sure that the concern was minimized. Turns out, all that needed to be done was a reset but his diagnostic to address my issues was very intricate and appreciated.

David

17 years of experience
37 reviews
David
17 years of experience
Chevrolet Cruze - Check Engine Light is on - Aurora, Colorado
David was on time, professionalisms & honest! I would definitely request him again and pass along to friends/family.

John

18 years of experience
18 reviews
John
18 years of experience
Dodge Ram 1500 - Check Engine Light is on - Memphis, Tennessee
Demonstrated good integrity. Advised me when work I thought needed done was unnecessary and was helpful in identifying issues that needed to be addressed

Robert

21 years of experience
17 reviews
Robert
21 years of experience
Chrysler 200 - Check Engine Light is on - Fort Worth, Texas
Robert did a good job working on my car and letting me know what's needed to keep my car driving smoothly.


More related articles

P0268 OBD-II Trouble Code: Cylinder number 3 Injector Circuit High
P0268 P0268 code definition Cylinder number 3 Injector Circuit High What the P0268 code means P0268 is an OBD-II diagnostic trouble code that is stored when the engine control module (ECM) detects that the cylinder number 3 injector circuit has...
P2237 OBD-II Trouble Code: O2 Sensor Positive Current Control Circuit/Open Bank 1 Sensor 1
What What the P2237 code means P2237 is an OBD-II generic code for the engine control module (ECM) detecting the O2 sensor for bank 1 sensor 1 and has an open circuit for the heater control circuit of the O2...
P3459 OBD-II Trouble Code: TP, MAP, or MAF Sensors
P3459 means the system has detected a problem with the vehicles TP, MAP, or MAF sensors due to defective cylinders, low oil pressure, or an oil block.

Related questions

Car independently drops from 70 mph to 5 mph

Hello. Unfortunately a permanent solution will be hard to reach because Land Rover continuously has problems with this particular make of transmission. In fact many Freelander owners have filed a class action lawsuit against Land Rover for such failures. In...

My vans ESC off Light keeps coming on

Hello. The cause of the Check Engine Light will likely also be the cause for the ESC light. If the engine computer sees a problem, it will disable the ESC. Your car's throttle is controlled by the engine's computer (PCM)....

My truck surges at low and idol speeds. Cold or hot. Sometimes quits when put in gear. Very low speed has a miss.

Hello and thank you for contacting YouMechanic. When you unplug the temperature sending unit the problem goes away but the engine light comes on. Check the plug to the sending unit for any corrosion or debris. Look at the pins...

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 (855) 347-2779 · hi@yourmechanic.com