Thought I had a speed sensor problem since the speedometer and both odometers were inop. When I started the car that morning I could have sworn I heard something snap/pop/break and then when I drove off that is when I found no speed indications. On-line troubleshooting said more than likely it was the sensor. Since I didn't have time to actually troubleshoot I went ahead and ordered one (only $40), well that didnt fix and I verified that the old one does indeed work. Put a drill on it and the everything from the sesnor to the dash works. So it apears that something in the transmission snapped. Also I cant see the shaft that spins the speed sensor turn at all.
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Did you have it check for DTC'S - diagnostic trouble codes ?
The speedometer is an analog gauge that is located in the instrument cluster. The PCM/VCM receives an analog input from the vehicle speed sensor and converts it to a digital signal containing 4,000 pulses per mile (PPM) for the instrument cluster.
The PCM/VCM sends this digital output (4,000 PPM) to the instrument cluster on a designated circuit. These pulses can be measured in Hertz (Hz) using a digital multimeter (DMM) on the AC scale. The PCM/VCM calibration is matched to the final drive and tire size of each vehicle. If the final drive or tire size is changed for any reason, the PCM/VCM must be updated in order to match the new final drive or tire size. If not, the signal will not be accurate for proper speedometer/odometer operation. An incorrect signal can affect the antilock brakes and the cruise control systems.
The speedometer system consists of the instrument cluster, vehicle speed sensor (VSS), PCM/VCM and related wiring. The VSS is a permanent magnet signal generator that sends an analog signal proportional to the propeller shaft speed to the PCM/VCM. The VSS mounts to the transmission tailshaft extension housing on 2-wheel drive (2WD) models and the transfer case output shaft housing on 4-wheel drive (4WD) models.
Repairs to the instrument cluster can only be performed by an authorized instrument cluster service center.
DTC P0502 Vehicle Speed Sensor (VSS) Circuit Low Input and DTC P0503 Vehicle Speed Sensor (VSS) Circuit Intermittent in Automatic Transmission - 4L60-E
- DTC P0500 Vehicle Speed Sensor (VSS) Circuit in Engine Controls - 4.3L
Important: If the instrument cluster is completely inoperative, refer to Instrument Cluster Inoperative .
Install a scan tool.
Raise the vehicles drive wheels. Refer to Lifting and Jacking the Vehicle in General Information.
Start the engine.
Place the transmission into drive for automatic transmission and third gear for manual transmission.
Compare the displayed vehicle speed on the Instrument Cluster with the monitored speed on the scan tool.
Does the vehicles speedometer and the scan tool both display 0 km/h (0 mph)?
You really need a Factory scan tool or equivalent to check this . The VSS is an input to the PCM/VCM . engine computer . You can test with a DVOM - digital volt ohm meter , for signal to engine computer .
I know most people don't like hearing this , but I suggest you take it to a ASE certified repair facility .
with the car on safety stands and running in gear check the speed sensor with a volt meter . The oil light should light up wen the ignition is on and go out a second or two after starting. Check the sender unit and wiring .
not a good idea to do a voltage test on a computer component, it can result in damage to the ECM. if only the speedometer is not working and the other gauges do work, the first place to start is the speed sensor, it is the most common issues with inoperative speedometers.
neoprene gear in transmission were the speedometer cable goes into transmission should not have a dished appearance if you pulll it out of transmission look at it from the side it should appear flat from the start of the gear to end of gear no dish down in center
The gear in the speedometer assembly is broken causing the odometer and trip odometer to be inop. You can either buy a new speedo head or buy a gear kit from an online source (google Ford speedo odometer inop)for the kit.
The speedometer is electronic, and uses pulses generated by the speed sensor to determine vehicle speed.
Disconnect the negative battery cable.
Unplug the electrical connector from the speed sensor (it's a 3-prong connector that clips onto the speed sensor, which is on the transaxle. Follow the cable down if you can).
Remove the three bolts securing the speed sensor to the transaxle.
Remove the sensor from the tranaxle. Be careful not the lose the drive link. It is a very small part that connects the sensor to the transaxle. It is at the bottom of the sensor, inside, and at the top of where the sensor connects to the transaxle. (It might have gotten lost during the engine switch, if they used your original speed sensor but connected to a transaxle that was with the new engine, or was removed from the car in order to connect it to the engine before it was installed). You might be lucky and find out that they simply didn't plug the connector back into the sensor.
Sensor installation is the reverse of removal.
I hope this is helpful.
Most likely a speed sensor is going bad (most cars and truck do not use mechanical speedometer cables anymore) most sensors are located near the differential in rwd cars or near the drive shaft on the transmission. Best bet is to get a Haynes manual for your car to help locate the speed sensor. Remove it and take it to the auto parts store so you can visually compare it to the replacement. Install the new speed sensor and it should restore your speedometer and odometer.