Help! fault code 72

[CHRLDO]

just ordered service manuals,but would like to fix this now.can anyone tell me, is fault code 72 a speed sensor (i'm having a speedometer problem). IF so, can you say which one? thanks for looking!

 

[BaggerBob]

I have a 94 manual and yes it seems that a fault code 72 is the speed sensor.

 

[Paul Higg]

Ditto to the above. I had the same code ONCE. I reset it last January (2008) and it has never come back. The speed sensor is mounted to the tranny. It's an easy fix. But if you have a dirty ground it can cause all kinds of problems.

What exactly is the speedo doing or not doing?

 

[CHRLDO]

code 72

thanks for replies! speedo is changing from mph to kph and sometimes to 0 mph. never goes blank. usually works fine until i get it up over 50 mph.then it goes whacky no matter what the speed.let it sit a while, then it works fine until i get it up around 50 mph.I thought there are speed sensors at the wheel hubs?

 

[Paul Higg]

The sensors at the hubs (front two are sealed, rear are not) are for the anti-skid system.

 

[CHRLDO]

code 72

thanks! i'll check ground on speed sensor on side of tranny.

 

[Paul Higg]

Plus, if I am not mistaken, I'd have to look in my FSM, I think the speed sensor on the side of the tranny is magnetic. If you do not have an FSM and need me to look it up lemme know.

Paul

And as Junk always says, grounds can cause a LOT of crazy problems, I saw it on jets ALL the time. Just the slightest corrosion or dirt can cause a high resistance as it is resisting the voltage.

Good luck and keep us informed, I always like to see what fixed something.

 

[CHRLDO]

code 72

ordered manuals-don't have them yet. any info would be appreciated. don't need a speeding ticket! got a picture of sensor?

 

[Paul Higg]

Send me an e-mail and I'll get right on it.

Paul

 

[CHRLDO]

code 72

thank you for taking the time to gather and send all that info, it's very helpful

 

[Paul Higg]

You're welcome Chuck. Please keep us informed. And as I said if your radio volume control is acting up too then there's your problem. Speed sensor, wiring, power, or grounds.

Best of luck to ya.

Paul