The speedometer was bouncing around and then all of a sudden it stopped bouncing and now the speedo isn’t working at all. What do you think it could be?
What vehicle? 1995 Toyota 4Runner SR5, (4wd, V6, 5-speed)
Are there any other symptoms? The Check Engine light comes on after the engine gets warmed up but goes off the next time it’s driven up until the time the engine gets warm again.
Diagnosis by phone: This truck has a cable driven speedometer (as opposed to the electric ones that come with the automatic transmission) and so this diagnosis is almost 100% sure thing. Typically the cable gets dry in the sheath and then starts to bind on the curves. This creates the noise. The bouncing motion is because the cable spins a little and then slows down and then spins some more. Don’t necessarily need a test drive on this one, but I do that anyway. I’m so sure on this one I head down to the dealership and pick up a speedo cable.
Final diagnosis: After the test drive it is confirmed that the speedo isn’t working, but the check engine light doesn’t come on. Even though the engine is at OT (Operating Temperature). Pulled the codes and got a 14 and 42. 42 has to do with the ECM not sensing a speed signal. (SPD signal is not input to the ECM for at least 8 seconds during high load driving with engine speed between 2,750 rpm and 4,000 rpm.) Most likely this has to do with the Speedo not working. 14 has to do with ignition signals getting to the ECM. This is an old code (due to the fact that the Check Engine light isn’t constantly on).
Solution: Crawled under the truck to start removing the speedo cable. When I get down there the speedo cable isn’t connected at the transfer case. Not sure how this could have wiggled itself loose, but it did. I reconnected the cable and tightened it up nice and snug. Once this has been done I took another test drive and now have a working speedometer with no check engine light. The speedometer sits solid on the correct speed all the way up to 75. Now I get to return the speedo cable to Toyota and eat a little crow. It just goes to show you that taking the time to properly diagnos a problem is always the best way to go. It can save you time and $$$ replacing parts that are still good.