A to Z Guide to Fix P0540 Duramax Error Code

What is the P0540 Duramax code? It is an error code that occurs for circuit malfunction in the intake air heater of the Duramax engine. This error code puts a signal when there is an abnormal input voltage in the intake air heater circuit.

This problem can stop the machine from working. There is a set of reasons for this problem. Since this is a critical problem code, you must solve the issues.

Here, you will find every detail of the P0540 Duramax code, including the reasons, symptoms, and solutions. You also get the steps to check and see the issues behind this code and hot solve them.

So, let’s explore further explanation.

P0540 Duramax Problem & Solution

Defect in intake air heater element relayThe engine cannot start
Defect in the heater elementThe engine starts late
Defects in blower motorsLonger cranking times
Burnt, corroded, and disconnected wiring and connectorsEngine stalls or short circuits in the engine Rough idling in low temperature
Defect in intake air temperature sensorDrop-in acceleration Rough idle Tough cold start Poor fuel economy Affected EGR valve
Open CircuitsIlluminated engine lightMotronic failure

There are several reasons for the p0540 error code. The most common cause is the issues or defects with the intake air heater element relay.

Moreover, this error can occur for the defective heater element in the intake air heater circuit, problems with connectors, open circuits, blower motors, issues with intake air temperature sensor, failure of PCM, and damage to the air duct.

Let’s discuss the solutions for specific reasons.

Defective Intake Air Heater Element Relay

The intake air heater element relay is the contact controller between the circuit and the heater grid. According to its control, the grid relay opens and closes the contact and starts the engine. If it fails, the engine cannot start.

Solution: When you find the intake air heater element relay defect, replace the faulty intake air heater and install a new one.

Damaged Heater Elements

The heater element works to warm the engine coolant. It makes it fast to heat the truck engine and then blows hot air towards the engine. Generally, a truck takes temp in the range of 0 to -20F and plug in a minute only of four hours. When the heater elements are damaged, it takes more than a minute of 6 hours.

Solution: If the heater elements are damaged or burnt, replace the heater elements.

Open Heater Circuit

The heater circuit gets open for some reason. If the coolant has leakage, the course may open. A short circuit can cause this problem too. Another reason for this open circuit is the failure of Motronic.

Solution: If the wires in the intake air heater circuit are corroded or open, repair it with the help of a service technician.

Shorted Connectors

If the connections are loose, then a short circuit can arise.

Solution: If the connectors are shorted, then you have to repair these connectors.

Bad Intake of Air

When the air heater intakes bad air, power reduces with time. Also, fuel efficiency and acceleration will also decrease. The engine also becomes idle highly. The check engine light keeps turning on.

Solution: When the air heater blower starts to intake bad air, replace the blower motors.

Issues with Temperature Sensor

When the temperature sensor of the intake air heater is damaged or disconnected or partially damaged, the check engine light will provide a signal on the dashboard. Besides, you will get a drop in acceleration, rough idle, late and tough cold start, poor fuel economy, and affected EGR valve. Misfires are also possible to happen.

Solution: If the temperature sensor is somehow disconnected, reconnect it. The temperature sensor can be completely damaged. In this case, you have to replace the temperature sensor.

Faulty PCM

PCM works as the central controller of the car. When it is faulty, an emission test failure may occur. Besides, the oddly-colored exhaustion may occur with foul smells. These symptoms occur before the PCM is completely damaged.

Solution: Fault in PCM is rare. After checking, if you find the PCM damaged, replace the PCM.

Troubleshoot P0540 Duramax Code

Since you have to find the defect for the P0540 code error before correcting it, troubleshooting steps are necessary. So, follow the steps below.

Step-1: When you get the P0540 Duramax error code signal, check the repair manual under the intake air heater application. Here, you will find how to detect the functions, location, color-coding, and routing issues. Follow the instruction and check thoroughly one by one.

Step-2: According to the repair manual, check the associated wiring and connectors through the visual inspection. If you find any damage, burnt, short circuit, or corroded effects, repair with the help of service professionals.

Step-3: After repairing faults that you found, delete the code and then test the system for fault. If you find the code until now and there is no problem with wiring and connections, go forward to check.

Also Read: Troubleshooting the P0380 Duramax Trouble Code

Step-4: The 2007 Duramax P0540 code can occur for the problem of 175-amp fuse. Then check it under the fuse box situated under the driver-side hood. Repair it if found faulty. Next, check the reference voltage, resistance, ground, and continuity issues. When running the check, you must ensure that you have disconnected the circuit from PCM. Otherwise, it will create a problem.

Step-5: At the next step, check the reference input voltage, resistance, ground, and continuity checks under the blower motors. Collect the readings and compare them with the suggested reading from the manual. If you find a mismatch, especially with the internal resistance, you must replace the blower motors. Next, check the internal resistance of the intake air temperature sensor. If it does not match the manufacturer’s specification, you must replace the blower motor.

Step-6: Delete the error code when all factors are okay and replacement is done. If you get P0540 Duramax IBZ after delete, you can be sure that there is an intermittent fault inside it. It is rare to find P0540 06 Duramax code in this stage. If the problem exists, then it is hard to repair too. This issue may need to allow the situation to increase with time. Then it will be easy to find the real issue. To solve this problem, you will need expert professionals.

Your problem will be solved within these checking procedures, and the P0540 code will not return. While performing the check, it is wise to get help from an expert technician. Extra cautions are a must as the heater element is involved in the system.

This Video Will Help You Too!

Frequently Asked Questions (FAQs)

What is code P0540?

There are error codes to show different engine issues. P0540 is one of them that shows circuit malfunction in the intake air heater system. When there are some issues, this code indicates a signal. When you get the signal, you have to check and find the problem step by step.

How to fix P0540?

Since the problem associated with the P0540 Chevy Duramax code is related to some of the parts of the intake air heater system, you have to repair or replace the faulty parts. The heater element, blower, meter, temperature sensor, etc., are involved in this system. You have to check all the parts, wiring, and connectors and solve the issues.

What is an intake air heater circuit?

The intake air heater circuit heats the air and then passes it to enter the engine. The machine works smoothly when the air is hot by consuming less fuel. It means that the hot air increases fuel efficiency.


To run smoothly, we need to know and understand the error codes that signal significant issues with the engine. P0540 Duramax is one of the essential error codes. You must realize this code deeply and know all the symptoms, reasons, and solutions to solve the problems.

Since you have found all the detailing steps here, you will understand what to do. Care is a must as it is about the heating element.

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D Conroy

Meet our senior writer and content manager of Automasterx. He has worked in several mechanical garages and mastered different vehicle diagnoses and parts repair. He never stops until finding out the ultimate solutions for any vehicle fault code. However, ensuring the only solid solutions for each vehicle malfunction is his core part of the duty, alongside analyzing fault codes and signals.

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