Tundra Speedometer Not Working? Step Inside

The speedometer is the part of any truck that we all take for granted. As soon as this part breaks, the vehicle is a hazard and traffic ticket waiting to happen. Unfortunately, there are many reasons why this part can stop working. We’re going to run through some of the most common reasons that will hopefully get you back on the road.

Sensors

This is always the first place to check when you have any issues with electrical parts of any vehicle. If you’re having an issue with an electrical components, it’s a good idea to check your vehicle computer for diagnostic codes. To get your codes pulled, you can:

1. Go to a mechanic and pay a diagnostic fee (most shops charge an hour of labor, some less, but they’ll put that time towards the repair)
2. You can visit your local chain auto parts store
3. You can buy your own OBDII port reader/scan tool. Some of the nicer tools – which run about $100 – have built-in software that will tell you what codes mean. Other readers are just simple little boxes that connect your OBDII port to your smartphone (usually via BlueTooth). These readers are cheap (you can get these on Amazon or eBay for around $20), and the smartphone apps for them tend to be free.

The most common trouble code for a speedometer problem will be P0500. If this is the code that you have it could mean any of the following problems could be causing the speedometer not to work.

• Faulty Vehicle Speed Sensor (VSS)
• VSS harness is open or shorting
• VSS circuit has a poor electrical connection
• Faulty Engine Control Module (ECM)

The easiest (and cheapest) to fix is the faulty VSS, with the faulty ECM being the most costly. Before you begin to make expensive repairs there are a few things that you can do first.

• Check all of the fuses
• Cleaning the sensor gear on the transmission may give you positive results before you have to invest in anything. Once you clean this gear, you can “clear” the error code in your engine computer using the OBDII tool and see if the code comes back.

If the problem persists and the code reappears (normally with the “Check Engine” light) then it is worth checking the VSS itself. Replacing this part may give you the results that you need, but there is no guarantee.

Just a Sensor or an ECM?

If you don’t want to invest in a new sensor knowing that the one fitted may be working perfectly fine, then there are other options. Given that the signal is taken from the sensor on the transmission to a Combination Meter and then to the ECM, you can check voltages at each of these points to get a sense of what might be wrong.

Attach a volt meter to the sensor’s outputs to see if there is any power being supplied when it’s turning. It should pulse between 0v and 4-6v. If there is no voltage coming from here, then you have a faulty sensor. If there is, then the problem is further up the line.

NOTE: You can’t really check voltages to see if an ECM has a problem, at least not without the right tools and training. If you suspect an ECM, it’s strongly suggested you get a professional diagnosis (or two) as these ECMs aren’t exactly cheap…Toyota Parts Center has 2007 Tundra ECM’s listed for $733 to $890, depending on engine and options.

Don’t Forget The Cluster

It’s possible that all of the electrical systems behind your speedometer are working, and that the issue is with the instrument itself. This is the least likely scenario, but once you have exhausted all other options this is where to look. Aftermarket speedometers will cost over $100 and can be a bit tricky to fit, so it may be worth getting your Toyota specialist to do this work for you.