How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Greg A Your Own Question
Greg A
Greg A, Master Troubleshooter
Category: Cadillac
Satisfied Customers: 8257
Experience:  Working with Electronics & Cars for 25+ Years
5229702
Type Your Cadillac Question Here...
Greg A is online now
A new question is answered every 9 seconds

2005 Escalade: intermittent..indicator..the tires showed the psi

Customer Question

I have a 2005 Escalade which has an intermittent "Service Tire Monitor" indicator that comes on after driviing. Took it back to the dealer 3 times and each time they said its a bad sensor which they have replaced on 3 different tires. The last time it came on while driving I cycled through each tire and noticed that the 3 of the tires showed the psi and one showed "- - -". After driving a bit more, the "Service Tire Monitor" would come back on, again cycling through the tires showed psi but a different tire now show "- - -". I don't believe this would be a bad tire sensor, any ideas what this could be or how to tell the dealer to check?
Submitted: 7 years ago.
Category: Cadillac
Expert:  Greg A replied 7 years ago.

Hello & Welcome,

 

Has the dealer done anything else, that you know of, besides replace the sensors for the tires? Is there anything on the paperwork about any Programming or Learning the sensors?

 

Thanks

 

 

Customer: replied 7 years ago.
No, they only state tire sensors. We bought the SUV used (a lease) and this is one of the items they are to fix. I do have photos i can send that I took while driving of the display, not sure it will do any good if you understand my problem.
Expert:  Greg A replied 7 years ago.

Hi again,

 

I think I understand, and from the symptoms you described (one of the psi readings being blank), it does sound like one sensor.

 

Let me send along a description of the system and the schematic. That way you will have more information to work with these folks.

 

graphic

 

graphic

 

I am assuming that you are dealing with a GM dealership that has the capability to read the specific error codes that come back from the system, and that has pointed them to a particular sensor. As you might be able to tell from the schematic, these sensors are just pressure sensors that transmit a signal to the receiver. If one of them is blank (like you saw), then that would point to that particular sensor.

 

So far they have changed 3 out of four, which only leaves one to go. If this was a GM dealership, it would surprise me that they did not get it right the first time, and that they would not have looked for something else wrong the second time (or the third). If this is NOT a GM dealership, and they don't have the right tools to properly diagnose the problem (scanner that will tell them what sensor has bad signal), then perhaps they were just "guessing" and have one shot left.

 

I believe there is also a calibration / relearn procedure that should be done whenever the tires are changed or rotated so that the system knows which tire to display as the problem. That is why I was asking about the paperwork details. Most shops will list the relearn procedure as a line item on the paperwork as a final step before testing.

 

I hope this helps and gives you more information to go on. Please let me know what happens or if I can provide more information.

 

Take Care, Greg A.

Customer: replied 7 years ago.
But since they have replace 3 of the 4 sensors and the tire monitor continues to show "- - -" intermittenlty on all the tires, why would replacing a 4th sensor fix the problem? It doesn't happen immediatly either, I could drive up to 40 miles before it comes on. Then the next time it comes on during the same trip, it may show a different tire failing this all going on driving at a steady speed on the freeway (not so free).
e.g.

LF Tire 34 psi
RF Tire 34 psi
LR Tire - - -
RR Tire 34 psi

Next time:
LF Tire 34 psi
RF Tire - - -
LR Tire 34 psi
RR Tire 34 psi
Expert:  Greg A replied 7 years ago.

Hi again,

 

You didn't mention that it was different tires each time, or I missed that point.

 

Is this a GM dealership?

 

Thanks

Customer: replied 7 years ago.
As shown in the initial question:

"After driving a bit more, the "Service Tire Monitor" would come back on, again cycling through the tires showed psi but a different tire now show "- - -"."
Expert:  Greg A replied 7 years ago.

I'm sorry - I missed that point in the original question.

 

Is this a GM dealership?

Customer: replied 7 years ago.
No problem.
Where is the BCM physically located and where in the schematics?
Expert:  Greg A replied 7 years ago.

Hi again,

 

The BCM is located on the lower left side of the Instrument Panel (IP) below the steering column. It is not shown directly in the schematic as it is part of the path between the passenger door module and the instrument panel cluster.

 

 

Customer: replied 7 years ago.
I'm sure you've seen this. Had been doing some research prior to you but still can't find anywhere that describes the problem I'm having.

refers to many docs here.
http://www.chevyavalanchefanclub.com/cafcna/index.php?topic=45508.5%3Bwap2

If they happen to be using the incorrect sensor, e.g. 2004 vs 2005 as decribed in the link above, would it just not work?graphic

I attached pics that was taken with iphone when it happened one of the many times.
Expert:  Greg A replied 7 years ago.

Hi again,

 

Your graphic did not make it, but you can try again if you want. You should be able to use the "little tree" icon on the toolbar to upload it if you would like. If you can't see the toolbar, click on Show Toolbar.

 

Yes, I had seen that bulletin. That is why I was asking if you were going to a GM dealership, which should have been aware of this.

Customer: replied 7 years ago.
Should be their
Expert:  Greg A replied 7 years ago.
I still don't see your graphic.
Customer: replied 7 years ago.
It's only a pic of the display console showing the what I mentioned above in each pic.
LF Tire 34 psi
RF Tire 34 psi
LR Tire - - -
RR Tire 34 psi

Next time:
LF Tire 34 psi
RF Tire - - -
LR Tire 34 psi
RR Tire 34 psi

I will be offline for about 15min, hopefully when I get back you may have something more. You wouldn't happen to know what frequency the RF is for the sensor?
Expert:  Greg A replied 7 years ago.

Hi again,

 

If this is a GM dealership, they should be aware of the bulletin and be using ALL the same (modern) sensors. They should also be doing the relearn procedure for all the wheels when the sensors are replaced. Here is that procedure, as a PDF file.

 

Learn Procedure

 

I do not know the particular frequency that is used.

 

Thanks, XXXXX

Greg A and other Cadillac Specialists are ready to help you
Customer: replied 7 years ago.
Chevrolet dealer
in Manassas, Va
I'll let you know what they come up with.

Thanks
Expert:  Greg A replied 7 years ago.

You are quite welcome,

 

If they said they would fix it, stick with their promise and make them fix it.

 

Take Care, Greg A.

Customer: replied 7 years ago.
Thanks for assistance.
Expert:  Greg A replied 7 years ago.
Good luck!