The P1574 error is a specific code that is triggered in Nissan vehicles. It usually comes up to let you know something is wrong with the Automatic Speed Control Device (ASCD). It will be triggered when the speed sensors malfunction or something is wrong with the transmission system.
The P1574 has symptoms that affect drivability and put you in a difficult situation. Such symptoms may include a loss of engine power, an inactive ASCD, a check engine light, or a service engine light coming on. You may also experience driving-related issues with difficulty in acceleration and changing gears.
Note that the best time to fix a P1574 error code is immediately after you notice it. Anything short of this puts your vehicle at risk of transmission failure. If this problem lingers, driving your car may constitute a highway risk and can lead to a road accident.
This article contains more details on what the error code P1574 means, its symptoms, its causes, and how you can fix it. Read on.
What does error code P1574 mean?
The P1574 is an error code concerning issues with the Automatic Speed Control Device (ASCD) speed sensor. Problems with the speed sensor mainly trigger the code.
What is an Automatic Speed Control Device (ASCD)? The ASCD is a function in many Nissan vehicles that allows the driver to maintain a particular speed when driving without the need to press down the accelerator pedal.
The ASCD feature allows drivers to set speeds between 40 km/h and 144 km/h. The driver can activate the feature by pressing the main switch to set the speed. The cruise indication will come up on the information display. Then the driver can then go ahead to set the speed.
How, then, does the ASCD function? The ASCD functions with the help of the speed sensors in the vehicle. The sensors feed the ECM with information about the movement of each wheel. Once the ECM gets the information, it is used for the ASCD.
Once the ASCD system is activated, the speed sensor plays a crucial role. First, the speed sensor helps the driver set speed by constantly feeding the current speed to the ECM.
Also, when the speed is set, the ECM and ASCD system monitors the vehicle’s speed through the speed sensor and ensures that the car does not go beyond or below the set speed.
Once there is a problem with the speed sensor, the ASCD system will malfunction, and the P1574 code will come up.
Also Read: Car Sensors and Their Functions
What are the symptoms of error code P1574?
The P1574 code does not come alone; it has some obvious symptoms that could reduce the driving experience. Some of th nbkbm., e symptoms of the P1574 error code include the following.
- The Automatic Speed Control Device (ASCD) or cruise control will remain inactive.
- The check engine light or service engine light will come on.
- Malfunctioning automatic transmission.
- The vehicle will hesitate to accelerate even when the acceleration pedal is depressed.
- Loss of engine power.
- Difficulty in changing gear.
- Incorrect speedometer reading.
A P1574 Nissan’s symptoms are basically what you get from a vehicle with a bad speed sensor.
What causes error code P1574
Below are the factors that could cause a P1574 error code.
Faulty speed sensor
Faulty speed sensors mean that the vehicle’s computer system will not get information about the car’s speed. When this happens, the ECM will have information used when the ASCD is activated.
In this case, the ASCD will remain inactive even when the driver activates the feature. As this goes on, the P1574 will be activated.
The wire does not just carry current to all electronic components; it also fosters communication between various components. The speed sensor, ECM and TCM are connected with the help of wire connections.
When the wire connection between this component is damaged, the signal transfer will either slow down or stop, depending on the damage. A situation like this will throw a P1574 code.
The difference in reading from both speed sensors
There are two major types of speed sensors used in a Nissan vehicle. There is the input speed sensor and wheel speed sensor.
The input sensor provides the ECM with information on the speed of the transmission’s input shaft. On the other hand, a wheel speed sensor provides the ECM with information on the speed of a wheel.
When there is a 5% difference in the value of both speed sensors, the P1574 code will come up.
Faulty transmission module
Also, a faulty transmission module could trigger the P1574 by altering the reading of the output speeding sensor. Sometimes, the transmission module does not send information from the sensor to the ECM.
The output speed sensor determines how fast the vehicle is going by measuring the movement of the toothed wheel on the shaft. Information gotten is then sent to the transmission control module (TCM). The TCM then sends the information to the ECM.
When the TCM is faulty, there is either no data sent to the ECM or inaccurate data is sent. Either case will trigger the P1574 code.
How serious error code P1574 is?
When the P1574 code is noticed during diagnosis, it should be treated with urgency. It is because the code affects the transmission system and can reduce the vehicle’s power output.
The P1574 error code has some serious symptoms that make driving the vehicle difficult and sometimes impossible. As the issue is left unattended, the worst symptoms become.
A P1574 error code could be a sign of a failing transmission system. Once the TCM fails, it could trigger the code. It would also cause the transmission system to malfunction.
In addition, serious symptoms like difficulty changing gears, loss of power, inactive ASCD or cruise control, and more will come up. It could make driving truly difficult.
Ignoring the P1574 error code could lead to transmission failure, and your engine can slip into limp mode.
How to Diagnose Nissan Vehicle P1574
The best way to diagnose a P1574 Nissan trouble code is by using a diagnostic tool. However, people do not know how to use the tool and often make mistakes. Below is how you can properly diagnose a P1574 code.
- Locate the diagnostic link connector, which is usually located on the driver’s side.
- Connect the scan tool to the connector.
- Enter any vehicle-specific information, like the vehicle identification number, if the scanner requests.
- Turn the key in the ignition, but do not start the vehicle.
- Proceed to select scan and then follow the necessary directions.
- The trouble codes will be displayed on the screen.
Once you have seen the trouble codes, like the P1574 error code, the next step is interpreting what it means. It will give you an insight into what could cause the error code to come up.
Once you select the P1574, it shows you “ASCD Vehicle Speed Sensor.” in this case, you know that the ASCD system is being affected by a damaged sensor, so you must have the speed sensors checked.
In some cases, it might not directly be the speed sensor that is the cause of the issues. Other factors related to the speed sensor could be causing the error code.
Check for other related error codes, like codes associated with the TCM. You can also physically inspect factors like the wire and other electrical components.
Common P1574 diagnosis mistakes
People make some common mistakes when diagnosing a P1574 error, especially when using a scan tool. Here you find the key ones.
- Disconnecting the battery before scanning the vehicle
- Not properly interpreting the error code
- Using inferior scan tools
- Clearing codes rather than fixing the issue
If you do not understand how to diagnose, interpret and fix error codes, it would be best if you took your Nissan car to a professional.
How do you fix P1574 Nissan?
The first step to fixing a Nissan DTC P1574 is proper diagnosis. A proper diagnosis can be made by using a diagnostic scan tool or physically inspecting components that could cause the error code to come.
It is best to use a scan tool, as a physical inspection can be time-consuming. Test the speed sensors using the scan tool and scan for codes related to the transmission system. You can physically inspect the wiring connection since the scan tool might not pick up issues like that.
Below are ways to fix a Nissan code P1574.
1. Replace faulty sensor
Using the scan tool, you can test speed sensors in the vehicle to know which one is damaged. Once you can figure out what sensor is the cause of the error code, you need to find it.
The speed sensor can be found with the help of the owner’s manual. Inspect the sensor housing and the wire connection for any damages as soon as you can find the sensor. If the sensor is damaged, have it changed immediately.
2. Change the damaged wiring harness
You can also use the owner’s manual to find the wiring connection for the speed sensor, ECM, and other parts related parts of the ASCD. Once you find the wire, inspect for corrosion, breaks, or exposed wiring.
If any damage is detected, change the wire immediately. Do not attempt to manage or fix the wire in any way.
3. Check and fix TCM issues
Issues with the TCM may be a simple malfunction, which could be solved by resetting the system. You can reset the TCM using a scan tool or disconnect the battery.
However, the issue could be a software issue or damage to the module. Issues kike this should be left to professional fix.
4. Check other electrical cause
Check other electrical damages like a blown fuse and damaged circuit. If there are damages, replace them. You can get the exact fuse related to the system using the vehicle manual.
Approx Repair cost?
Fixing P1574 Nissan Maxima error code will cost between $150 and $300, excluding labor costs. You will spend an amount between $100 and $200 if you will be hiring an expert to have the work done for you.
If the issue is not with the speed sensor, then it might cost more or less depending on the issue. If it’s a wiring issue, it will cost between $300 and $1000 to replace damaged wiring harness.
Also Read: P0430 Code: An In-depth Analysis
What is an ASCD speed sensor?
The ASCD uses two types of sensors: the output and wheel sensor. The output determines the vehicle’s speed by getting information from the transmission system and then feeding the information to the ECM. On the other head, the wheel sensor can be found on one of the wheels.
It collects data on the wheel’s speed and transmits the information to the ECM in the form of signals. The ECM then uses the information to execute ASCD.
What is the purpose of the ASCD?
The ASCD is a feature in Nissan vehicles that allows drivers move at a particular speed without the need to press down the acceleration pedal. It is put in place to discourage the exhaustion of drivers from to press down the acceleration pedal when driving on highways.
The feature can be activated by using the ASCD switch located at the side of the steering wheel. It will automatically deactivate once the driver hits the brakes.
What is ASCD on a car?
An ASCD system in a car is a cruise option that reduces the stress of driving by allowing the vehicle to maintain a particular speed without depressing the acceleration pedal.
The ASCD works alongside the ECM. It works with the use of speed sensors that transmit signals about the vehicle’s speed. ECM then uses these signals to execute ASCD once the feature is activated.
Is a speed sensor AC or DC?
The wheel speed sensor generates an alternate current (AC) signal. The signal allows for an increase in frequency as the vehicle’s wheel speeds up. At the same time, the output speed sensor also generates AC signals; this is because the toothed tone ring also acts like the wheel; the more it rotates and passes the sensor, the more increase in the AC signal generated by the sensor.
Diagnosing the P1574 error code can be tricky, mainly because you may not have electrical and technical knowledge. It is advisable that when the error code comes up during diagnosis, you take the vehicle to an expert for proper diagnosis and fix.