kalali

Tachometer stopped working all of a sudden. Everything else appears to be working and all the fuses check out fine. Any idea where should I start looking? Thanks in advance.

fastnoypi

i would guess its getting the signal from the crankshaft angle sensor.

kalali

Thanks. The only wild card is she needed a jump and I noticed the tachometer when I took the car out for a test drive. My mother in law now drives the RX and didn't even notice it not working when I pointed it out to her so I don't know if I damaged something during the jump or it was dead before I got there.

fastnoypi

Good luck on tracking it down. Its just my educated guess based on the 1MZFE diagram. Check out page 38 of the ECU system diagram. If you can find the ecu pin outs, try pushing and wiggling the wire associated with the rpm signal.

http://alflash.com.ua/RX/1MZ-FE_Engi...emRX300_99.pdf

kalali

Thank you very much. This is very helpful. I'll keep the forum posted if I make any progress.

Edit: The diagram shows an "RPM Sensor" near the bottom/underneath of the engine. Hard to pinpoint the exact location but probably reachable from underneath. I might get lucky and find a loose connector.

salimshah

There maybe a soft problem ... try disconnecting the battery terminal for about 20 minutes.

May not work but wont cost anything.

Salim

kalali

Thanks. I went over the car and couldn't find anything obvious. Will disconnect the battery next and see if that helps. Fortunately for everyone else, this appears to be a very rare issue.

maxSteel

The diagnostics manual says

1. Connect a tester to the OBD port, watch the live readings to see if the tachometer reading is moving. If so, proceed to check the tachometer itself
2. Check the harness and connector between the combination meter and the ECU
3. Check the igniter circuit

kalali

Thank you. Unfortunately I'm not equipped to perform that level of troubleshooting. I don't even know what/where some of those components are, e.g. igniter circuit, combination meter, etc.
Where is the ECU located?

maxSteel

You should get an OBD II code reader that does live data. In this case you need it to read live data. But you also need it to read and clear fault codes.

The combination meter is the instrument cluster with speedometer, tachometer, etc.

The ECU is on the passenger side inside the fender, to the right of the glove box. There are nice pictures of it in the thread on "15 minute knock sensor repair".

kalali

Thanks a lot. Appreciate the input. My cheapo code reader only reads/clears faults.

kalali

Just wanted to circle back and close this issue. Finally had the opportunity to do what Salim had suggested and voilà the tach is back to normal. In the meantime, learned quite a bit about the car's electronics...... Simple things first, always.
Thanks everyone for your valuable inputs.

fastnoypi

great news..glad a simple solution worked out for you