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YOUR RESEARCHTachometer not working.
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problem
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No successful repair reported for this finding.
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Reported cause
Thanks for the update on what turned out to be the problem.
Leading evidence: 'problem' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'problem' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check connection' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion
The cps is obvioisly sending the signal to the dme because its running but its not reaching the dash or obd2 plug.
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Suggestion
Freaked me out , ($$$$) but if the bail that holds the connector isn't set correctly each section can shut down.
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11 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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2003 996 manual transmission Carera cabriolet - My tachometer stopped working and center message screen reports "Engine Fault", but otherwise the car runs fine. My ODB2 reader says the car does not report any fault codes. However the ODB2 reader does display engine RPM. Any tips on where to start looking for tachometer faults?
Guessing u have a wiring issue between the dme and the guage cluster. The cps is obvioisly sending the signal to the dme because its running but its not reaching the dash or obd2 plug. Nowhere near my bently manual so cant help any further with the wiring.
Thanks for your reply! The ODB2 does report the engine RPM as the car runs, so some data is getting to the plug. It just doesn't report a fault. I'm not sure what dme (engine computer?) or cps (crank position sensor?) mean. I'll start looking at wiring harnesses I guess.
Remove the Dash Pod and see if one of the 3 connectors is loose. I want to say it's the Blue Connector on mine.
Freaked me out , ($$$$) but if the bail that holds the connector isn't set correctly each section can shut down.
If you haven't ever removed Pod I think the is some instructions at Renntech.org.
Be careful with Hazard switch.
Then i agree with post above. Check your connection to the cluster.
Also yes dme, engine computer, cps is the crank position sensor. The cps generates the signal that the computer uses to determine rpm and motor position. Since the car is preforming correctly it points to the gauge connection.
Solved! Nothing was wrong with my ECU or instrument cluster. The tachometer was just fine. It simply wasn't getting a signal to display. I have since learned that the tachometer gets its RPM signal from...the alternator! Four months after my original post, my alternator stopped working suddenly and completely. Drove home on battery and ordered a replacement. Two wires are connected to the alternator, a heavy positive voltage cable that feeds electrical current to the car, and a small sensor wire that feeds the tachometer engine RPM. Installing a new alternator brought the tach back to life and cleared all the warning/indicator lights. I've attached a picture of the dash (sorry for the glare) with the lights lit before total failure of the alternator. Cruise control, temp gauge and fuel gauge all worked fine despite the warning lights. Only the tachometer wasn't working. Once the alternator failed completely, every light on the dash lit up. Car still ran fine, of course, just drained the battery on the drive back home. Hope this can help someone else.
Green cruise control light, engine temp light and low fuel light all permanently on when my tachometer lost it's signal from the alternator. Cruise control, temp gauge and fuel gauge all worked fine despite the lights.
Wow! Thanks for the update on what turned out to be the problem. Who would have thought the alternator provides the signal for the tach? I'm still not getting it. Wonder what happens to those who put on an underdrive pulley on the crank...
Four years late here but I felt I had to butt in - I dont think the alternator sends the engine speed to the cluster. It does have 2 wires to it and one does go to the cluster but it (a .5 Blue wire) goes to the charge indicator input not the engine speed input. The engine speed input is a .35 Violet/Green stripe coming from the engine speed signal output on pin 80 of the DME and the DME generates this signal from the CPS sensor.
DME:
Cluster:
Alternator (generator):
Perhaps a bad alternator was somehow affecting the engine speed system but it does not provide the signal to the cluster.
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