A malfunctioning coolant temperature sensor is the most frequent cause of your car’s temperature gauge remaining on chilly. Incorrect wiring between the cluster or the sensor may also be to blame. In some circumstances, the engine may not heat up adequately due to a jammed thermostat.
Let’s delve a little deeper into each of the underlying issues. Here is a more thorough list of the most frequent reasons why a temperature gauge remains on the cold setting.
In This Article...
Faulty Engine Coolant Temperature Sensor
As we said, the coolant temperature sensor itself, which sends the data to the cluster, is the most typical issue with an erroneous engine temperature reading.
While some car models have two temperature sensors, others only have one. The temperature of the engine control unit and the gauge sensor are typically both measured by the same sensor in versions with a single sensor.
If your car model has two coolant temperature sensors, the engine control unit uses one and the temperature gauge uses the other.
With a multimeter, engine temperature sensors are simple to test, but you must determine the proper readings for them. In your service manual, you can frequently find additional instructions on how to test them.
If you do decide to repair one of these, make sure, if you have two of them, that you also change the sensor that connects to the temperature gauge.
Broken Wirings
You should examine the sensor’s cables to the gauge or ohm measure the sensor from the cluster connector if your automobile has two temperature sensors and one separate for the gauge.
If you just have one sensor for each, there may be a wiring issue between the gauge and the ECU, or there may be one (more likely) between the sensor and the ECU. Look for any damaged wires connecting these parts.
The best technique to identify damaged wiring is to use a multimeter to measure resistance coming from every direction of the wires. However, you might need to let your mechanic take a look at it as this calls for some basic electronic car understanding.
Your repair handbook may also have information about this. To accurately measure the wiring in your car, see the wiring diagram.
Faulty Gauge/Cluster
The temperature gauge is the next issue. On modern cars, the majority of temperature gauges are attached to the instrument cluster. You may be able to fix any poor solderings you find or replace the temperature gauge in some circumstances.
You might need to swap out the instrument cluster in other clusters. If you do not know how to fix the soldering yourself, you can frequently leave your instrument cluster in the hands of a professional.
However, malfunctioning clusters are uncommon, frequently quite expensive, and require coding after replacement. Therefore, before deciding to replace the cluster, it is advised that you check the other items first.
If you have some understanding, you can also use an Ohm tester to test the cluster temperature gauge.
Corrosion in plug connectors
A common issue with a broken temperature gauge is corrosion in the connectors. The connectors at the sensor, the engine control unit, and the cluster should all be cleaned and sprayed with electronic cleaner.
If corrosion starts to show, there may be an issue with the connectors’ sealings, and you may need to inspect them to make a long-lasting repair or replace them to prevent further issues.
Bad Thermostat
The thermostat limits the amount of coolant that can pass through the radiator. The temperature might not reach the ideal temperature if this becomes locked on wide open.
If you drive vigorously enough, though, this will frequently cause your temperature to rise somewhat from the minimum mark. Your thermostat may be malfunctioning if the temperature gauge is rising slowly.
How much does repairing a temperature gauge cost?
Engine temperature sensor replacements typically cost between $150 and $193. Parts cost between $66 and $88 while labor costs range from $82 to $105 per hour.
Is the temperature gauge fused?
One per se doesn’t exist. The instrument cluster will be powered by a fused wire (your owners manual should specify which fuse), but the temperature sensor is supplying fluctuating “resistance to ground,” which is being reflected by the temperature gauge in the dash. The resistance across the sensor will be higher for a cold engine and lower for a hot engine. Because of this, the temperature sensor and temperature gauge in your car are tailored to a particular temperature range. If you require additional assistance, a qualified expert from YourMechanic may examine the electrical wiring and replace a fuse.
Where is the sensor for the temperature gauge?
The temperature of the liquid coolant is measured by an ECT, or engine coolant temperature sensor. A popular engine cooling temperature sensor is an NTC (Negative Temperature Coefficient) thermistor, meaning that as the temperature rises, it becomes less resistive electrically. The ECT sensor’s tip extends into a passageway of the cooling system and is submerged in coolant.
Many automobiles feature multiple coolant temperature sensors. The primary ECT sensor (ECT sensor 1) is typically mounted on the thermostat housing, cylinder head, or block, which is close to the thermostat.
Another coolant temperature sensor might be mounted in the radiator or another area of the engine.
In some vehicles, the ECT sensor is supplemented or replaced by a cylinder head temperature sensor, or CHT sensor. Similar in operation, the CHT sensor (seen in the photo) does not dunk in coolant; instead, it gauges the metal temperature of the cylinder head. This enables the CHT sensor to accurately gauge engine temperature despite coolant loss. This might occasionally aid in preventing overheating.
The primary computer is coupled with an ECT sensor (powertrain control module or PCM). The PCM provides a reference voltage (usually 5 Volt) and continuously tracks the signal from the ECT sensor. When the temperature exceeds a predetermined threshold, the PCM changes the engine performance based on this signal and turns on the electric radiator fans.
The PCM activates the Check Engine light and saves the associated issue code in its memory if the sensor’s signal is absent or falls outside of the predicted range.
The sensor for the temperature gauge is where?
A damaged coolant temperature sensor is the most frequent reason for inaccurate temperature readings (CTS). The component, which is typically found close to the thermostat of a car around the base of the radiator (see your owner’s manual or repair manual), can become clogged and break down.
- Check to determine if the CTS is delivering real-time temperature readings using an OBD2 scanner.
- If it isn’t, you have a problem. The component must be changed.
- For 15 to 20 minutes, allow the coolant in the automobile to cool.
- You should jack up the front of your car for more clearance.
- Lift the radiator cap off.
- In accordance with the instructions in your car’s repair manual, drain the radiator.
- Disconnect the cabling connector for the temperature sensor.
- The temperature sensor must be removed.
- Place the new temperature sensor in place.
- The wire connector must be reconnected.
- Make sure the coolant plugs are all tightly fastened.
- Reapply coolant, then cover the reservoir with its top.
- Drop the automobile.
- Start the car.
- Watch the temperature gauge to make sure it is reading accurately.
- Take it for a spin.
- Make sure the coolant level hasn’t decreased by checking.
- If so, fill it up as needed.
- You’re good to go if everything is in order.
Thermostat problems rank second in terms of defect frequency. This tiny component, which controls how much coolant moves from the radiator to and from the engine, can get stuck open or closed. Both are detrimental to your engine. (Check your owner’s manual or maintenance manual.) The thermostat is typically found near the top or base of the radiator. A thermostat can only be tested by entirely removing it and putting it in a pail of boiling water to check if it opens. Here’s how to diagnose and fix a broken thermostat.
- find the thermostat
- Jack up the vehicle’s front end for more clearance.
- Take the thermostat off.
- Immerse the thermostat in nearly boiling water to test it. If it stays closed, it is broken and has to be replaced.
- Change the thermostat.
- Put the reservoir’s cap back on after adding the coolant.
- You’ve finished it if everything went smoothly.
The entry of air into the radiator hoses is another typical cause of a broken temperature gauge. Near the thermostat or temperature sensor, air can collect and produce inaccurate readings (or no readings at all). The effectiveness of the car’s overall cooling system may also be impacted. How to identify and treat air in your hoses is shown here.
- Your car’s front should be jacked up to help with air removal.
- Start the automobile while the radiator cap is off.
- If there is air in the system, it will burp up as the coolant starts to cycle through the engine.
- Allow the car to idle for 15 to 20 minutes to warm up.
- Replace the radiator cap after being certain that all the air has been sucked out (the burping will cease).
The typical do-it-yourselfer might require the help of a pro to identify and repair a broken instrument cluster. It’s more likely that the gauge cluster itself has a problem if you’ve already investigated the three potential causes listed above and none of them were the problem.
Where is the sensor for coolant temperature?
The coolant temperature sensor (CTS), which allows for maximum performance, is often located someplace close to the engine thermostat. The CTS’s tip is most likely just adjacent to the engine’s coolant.
The sensor measures the temperature that the thermostat and/or the coolant itself are emitting. The on-board control system receives the temperature after that. The computer in your car will then use this temperature data to decide whether to keep running the engine or change some of its operations in an effort to maintain a desirable engine temperature.
The cooling fan may be triggered to turn on or off as soon as the control system receives the temperature from the CTS. Additionally, it can indicate that a richer fuel mixture is required or that the exhaust gas recirculation should be opened.
Is a cold engine dangerous for your car?
Answering this question is challenging. The majority of knowledgeable auto enthusiasts will tell you that using an engine for any length of time outside of its ideal temperature range is simply unhealthy. Having said that, simply because you chose to drive it to the mechanic cold won’t result in an exploded engine.
The issue can develop into a serious problem if you choose to fully disregard it and keep driving the car for several weeks or months.
Herein lays the primary problem. Undoubtedly, a cold engine ages more quickly. That is unavoidable. Modern automobiles do, however, feature a cooling system connected to the ECU. The ECU feeds the engine a richer mixture to warm it up more quickly when it is cold.
Running your engine cold all the time will almost certainly result in higher fuel usage all around. Additionally, many engine components will have increased levels of carbon accumulation.
Excess gasoline entering the exhaust is the most harmful result of feeding an engine a fuel-rich mixture. More specifically, the issue arises when unburned fuel enters the catalytic converter and severely harms it.
Why does my engine have a cold start?
An engine is said to be running cold if it hasn’t reached operational temperature. The following are the main causes of low temperatures: a broken thermostat. a faulty sensor for engine coolant temperature.
How much does a coolant temperature sensor replacement cost?
Depending on the vehicle model, the cost of replacing the coolant temperature sensor can vary greatly.
Some coolant temperature sensors, which are present on many vehicles, are quite easy to repair, but others can be rather challenging to get to. Each car can have a different cost associated with buying a coolant temperature sensor.
A coolant temperature sensor typically costs between $20 and $80, whereas labor can cost anywhere between $50 and $250. The overall cost to replace an engine coolant temperature sensor could range from $70-$330.