3 Essential Things to Know About Your Car’s Tachometer

The tachometer is located on the dashboard next to the speedometer. It measures the revolutions per minutes (RPM). The tachometer can be a digital display or on a calibrated analogue dial. They are on both automatic and manual vehicles.

Purpose of the Tachometer

The tachometer shows the rotation of the engine’s crankshaft. The purpose of this is to help the driver in choosing the right throttle, and gear for driving conditions. For vehicles that have analogue dials, the danger area is marked in red. If the tachometer is driven in the red for too long, this can cause overheating, inadequate lubrication, and excessive wear on the engine. This can shorten the lifespan of the vehicle or cause the engine to fail.

Parts of the Tachometer

The dial of the tachometer has numbers ranging from one to seven on most vehicles. An indicator points to the numbers showing where your RPM is at while you are driving. There is a yellow area that means you are just starting to enter the danger zone. The red zone is normally around numbers six and seven and is the danger zone.

Potential Problems with a Tachometer

A blown fuse is a potential problem with the tachometer. Check the fuses to ensure they are properly functioning. Bad wiring can also be the cause of a malfunctioning tachometer. If you are getting erratic readings, this can be a sign of bad wiring. Another potential problem is calibration issues. If you notice the RPM readings do not coincide with the motor, then it may be time to have the mechanic look at the vehicle. By doing so, they can diagnose any problems that are going on. If you have a digital display, the LED lights may go out on the tachometer, or may not display correctly. Typically, a burned out LED is the cause of this. If you are still having issues with the tachometer after troubleshooting various problems, you may just have a bad tachometer. If this is the case, the tachometer needs to be replaced by a professional.

The purpose of the tachometer is to read the rotation of the engine’s crankshaft, which is shown in RPM. It is located next to the speedometer. If the dial goes into the red area, there may be a problem with your engine or the tachometer. If this is the case you can contact YourMechanic for an inspection.


The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Clean a Throttle Body
A throttle body needs cleaning when the engine idle is rough, the engine stumbles through acceleration, or the Check Engine Light comes on.
P0337 OBD-II Trouble Code: Crankshaft Position Sensor A Circuit Low Input
P0337 means that the crankshaft is suffering because of low voltage. This could be due to sensor not being aligned properly or electrical problems.
B2105 OBD-II Trouble Code: Throttle Position Input Out of Range Low
B2105 trouble code means there's a problem with the throttle position input range in a 4WD system, caused by a loose harness or short circuit.

Related questions

High idle after throttle body cleaning
The idle is going to be high at first until the computer relearns the idle again. Cleaning the throttle body allowed more air to enter the engine, and the computer is compensating by adding more fuel. The idle will relearn...
My car is shutting down in low gear/idle immediately after transmission rebuild & minor updated engine parts
First, I am sorry to hear that you are having such a poor experience with this repair. Unfortunately, there is only one way to know if your car is ready to be driven without any problems - you will need...
Misfires while idling
Hello there, thank you for asking about your 1986 BMW 635CSi. It sounds like you've checked all of the low hanging fruit. The previous owner may be right - some vehicles (only German ones come to mind) can develop a...

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