RPM is very Low. Please Help

[Jason_Wang]

My baby car(92 Camry,3VZ-FE) cause me creazy now. when I wait for the red light,the rpm is low as 400 rpm(Normally, it should be 800rpm), steering wheel shakes. I check the error code(#42) from "O/D" is speed sensor error. In fact my speed meter does not work, I check the shaft on speed sensor, it is ok. I think the speed sensor is no business with rpm. I alreay change air filter and clean the IDLE intake. Is it true the speed sensor cause this issue or others cause it?
Thanks a lot.

Jason

[BMR]

I doubt the error code 42 has anything to do with the idle problem, but I'm not 100% sure about that.

I'd guess your IAC valve needs a good cleaning. It's difficult for intake cleaners to get in there a do a great job. When I took mine apart, it was fouled with a heavy build up of HARD carbon deposits; had to use a soft plastic scraping tool to chip it off. Here's a good DIY thread showing how it's done:

How to guide, clean IAC Valve 56k, be patient! BIG PICT

[Jason_Wang]

Originally Posted by BMR

I doubt the error code 42 has anything to do with the idle problem, but I'm not 100% sure about that.

I'd guess your IAC valve needs a good cleaning. It's difficult for intake cleaners to get in there a do a great job. When I took mine apart, it was fouled with a heavy build up of HARD carbon deposits; had to use a soft plastic scraping tool to chip it off. Here's a good DIY thread showing how it's done:

How to guide, clean IAC Valve 56k, be patient! BIG PICT

Finally, I order a good trans speed sensor. then Replaced the old one. RPM comes to normal. Speed meter on dashboard comes to normal too. Problem resolved. Thank you!. I will focus on next question is air bag (ari bag light always off). is there any advise how to dianostic it, using dianostic box underhood? Someone told me that there are gun powder in air bag, so I have a little bit to do that. Any advise?

Thank you all guys.
Jason

[TedL]

Originally Posted by Jason_Wang

Finally, I order a good trans speed sensor. then Replaced the old one. RPM comes to normal. Speed meter on dashboard comes to normal too. Problem resolved. Thank you!. I will focus on next question is air bag (ari bag light always off). is there any advise how to dianostic it, using dianostic box underhood? Someone told me that there are gun powder in air bag, so I have a little bit to do that. Any advise?

Thank you all guys.
Jason

If the air bag light is always off, as you wrote, even during self test at startup, first thing to do is check the bulb to make sure it's not burned out.