Transmission Sensor ?

I have a 2002 Elantra Auto...

I had a problem a year ago where i'd be driving at highway speed and the transmission would drop to 3rd (fail safe) and would only return back normal if i pulled over and switched off.. This turned out to be the pulse generator.

A new problem is now effecting me... From switching on i drive from 1st to

2nd then high revs before jumping to 3rd.. Then i remain in 3rd when speeding up or slowing down.

I switch off.. back on and it drives like normal.. I switch off back on and the same error occurs. I've not determined if this is from a cold start only but it's at the shop now so we'll see.

Any ideas what the problem could be?

Reply to
jmh_ottawa
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The high revs are disturbing. That could indicate an internal transmission problem. In any event, it's going into failsafe. The shop will check for error codes (hopefully) and this will help them know what's going on.

Reply to
hyundaitech

I need to check and clean the pulse generator connection on a 2001 Accent AT. Is this a DIY or take to a service center?

Reply to
accent

You could probably do this yourself. If you've got a code P0722, there's a reprogram available for this as well.

I'd recommend getting an account at

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(if you don't already have one; it's free) and checking TSB 03-40-016. You won't be able to do the reprogram yourself, but it gives instructions for the connector as well.

Reply to
hyundaitech

TSB 03-40-016 describes 2 procedures, pulse generator-b inspection and TCM reprogramming. Are these 2 separate procedures which can be performed independently?

Pulse generators break and connections go bad, I have no issues with these types of expenses. But if the TCM reprogramming is needed to address defects in the firmware design then Hyundai should provide this at no cost to the consumer. My 2 cents.

Reply to
accent

Yes, you can do the inspection and cleaning independent of the reprogram. It's my understanding that the reprogramming addresses the issue of electromagnetic interference in the vehicle speed sensor signal and reducing the computer's sensitivity when looking at the speed sensor. If you're within the 5/60 warranty period, the reprogramming should be covered by your new vehicle warranty. If not, you're out of luck. Sorry.

Reply to
hyundaitech

  1. Locate the pulse generator under the battery tray. Disconnect the pulse generator connector (blue) and remove the pulse generator male connector (black) from the bracket.

The pulse generator-b is not as illustrated in TSB 03-40-016. Pulse generator male connector is blue. It is not clear whether the bracket and male connector is a single unit. Do I slide the male connector off the bracket and pull the connectors apart or are they locked together?

Reply to
accent

You'll slide the male connector off the bracket so you can get to it. You'll need to pull the connectors apart (there's a little release tab) and then check the resistance. Rather than trying to figure out which is which, I just ohm test both.

Reply to
hyundaitech

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