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My car has the P0462 (Fuel Level Sensor low input) P0500 (Vehicle speed sensor circuit fault) but both the speedometer and the fuel gauge appear to be working normally. However the tach bounces between the approximate engine speed and 0 (not all of the time but frequently).

The car doesn't have any other symptoms it runs and drives fine. Doesn't bog down or have any other known issues.

I am not sure where I should start with troubleshooting this issue as it seems odd that these problems could be unrelated given that they basically started at the same time. Is it possible that the P0500 has the same cause as the tachometer?

Engine is 1.8L with a manual transmission.

  • Have you cleared the codes and if so, did they come back? Sometimes the PCM will pick up a fault because which ever system it is "blips" (quits working for a very short period). You don't really notice it, but the system continues running from that point on (until the next time). If the fault does not come back after clearing, I'd suggest this is the case. It may be an indication these systems are failing (fuel level sensor and vehicle speed sensor) and might need to be replaced in the future, but no big deal right now. – Pᴀᴜʟsᴛᴇʀ2 Aug 23 '14 at 14:02
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You need to check the speed sensor at the transmission with an Ohm meter and find around 25 Ohms. One of the wires, usually purple attaches, to the back of the instrument panel. Make sure of a good connection and continuity in the wiring. Another fault that can occur is that the driving wheel on the transmission output shaft is slipping on the shaft, which is a major job to rectify. The fuel sensor fault will be differant and unconnected to the speed sensor. To test the sensor fill the tank to full with any fault code on. Check the gauge reading. Then, and only then, clear the codes. If the code now returns you will need a new fuel sensor. Be careful on clearing codes, you get a lot of suggestions to clear the codes and see if they come back. Its what people who do not really know what they are talking about suggest. If the codes are cleared before an effective repair is completed, or a set procedure is not carried out, many engine ECU's will not be able to complete a drive cycle and faults will be masked, the CEL light may not even come back on. This means that the vehicle will never reach ready status and other systems can be irrepairably damaged.

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After replacing the speed sensor and the fuel level sensor and resetting the codes. A new code came up U1001 (CAN communication) in addition to the other codes. I tracked the problem back to the instrument cluster where the fuel level sensor and the speed sensor signals travel through to the ECU. Replaced the instrument cluster with one from a junk yard, cleared the codes and the issue with the tach went away and the codes haven't come back.

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