Please help....dealer is saying wheel size is the reason for limp mode...

R

Rxheaven1

Member
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15' Mazda CX-5 GT
*Update*
The service rep said that the ABS sensors are good and that NO codes are being tripped. The problem still persists and they are removing the wheels to rule that out as the culprit.

*Update*
They were able to put OEM wheels on the car and the problem still persists. They requested follow through from Mazda whether to replace the transmission or send out a specialist to inspect the car. So far, they still have NO idea what it is.

*Update*
After a week of waiting for the decision and getting my data together, Mazda will cover the transmission. Just waiting for the tranny to come from Mazda.

Hi all,

My wife has a 2015 CX5 GT AWD with just over 14k miles on it. The car was originally lowered on Corksport spring but ended on H&R's. That was over 5 months ago. I then installed some Rota Grids with as close to Oem height (wheel and tire size) about 3 month ago. We are in SF and have driven the car to LA and back 3 times along with the daily commute. My wife was making a 3 point turn and as she accelerated forward, the car jolted and 3 loud bangs (like the tranny or transfer case disengaged) and the car lost power. It went into Limp mode. No lights on the dash came on. We had the car towed to Royal Mazda who instantly blamed the wheels and suspension. My question is can this be true? They claimed to reset it and as we pulled out, it did it again. So now they want to put the Oem set back on. I find it very hard to believe that we drove the car for 3 month at more than 6k miles and now it happens. Also, the wheel/tire combo is .2 inches smaller than Oem size and 7 rotations a mile more than Oem. WTF?

Any advice would help! We've had multiple AWD cars with different wheels and lowered and never had an issue.

Thanks.
 
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If all the wheels are the same size than there shouldn't be an issue. Their are a number of people here who have aftermarket wheels and tires with lowering springs without problems. You may find this information in your owners manual. You can also take it to a different deal too.
 
V8toilet said:
If all the wheels are the same size than there shouldn't be an issue. Their are a number of people here who have aftermarket wheels and tires with lowering springs without problems. You may find this information in your owners manual. You can also take it to a different deal too.
Click to expand...

That's what we are thinking. We want to take it to our regular dealer/service. I am also going to call my old service rep to see what he thinks (unfortunately he left for Lexus).

Can anyone look in their manual? Ours is in the shop so we can look. We want as much "ammo" before talking to them next week.
 
OK first thing. The wheels are not causing your car to go into limp mode. What I would check however is your ABS sensor. It attaches to the strut. It has to be removed anytime a spring on the front strut is changed. It is held on by a clip, that when improperly removed, will break it. The common solution (if used at all) is to re-secure it with a zip tie. When this eventually fails, the sensor is free to dangle on the front axle, which WILL fray it, and if it exposes the wire and shorts will send your car into limp mode. My advice is to check behind your wheel and see if the wire is hanging down, and if it isn't check to see if it's frayed (perhaps it was dangling before but not from the last install). If it is the sensor it's about $40 to replace.

The wire comes out of the wheel well cladding, attaches to the holes in the strut (with the clip) and leads into the brake.

ybKiDzO.jpg


Z5mxHZ4.jpg
 
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Chris_Top_Her said:
OK first thing. The wheels are not causing your car to go into limp mode. What I would check however is your ABS sensor. It attaches to the strut. It has to be removed anytime a spring on the front strut is changed. It is held on by a clip, that when improperly removed, will break it. The common solution (if used at all) is to re-secure it with a zip tie. When this eventually fails, the sensor is free to dangle on the front axle, which WILL fray it, and if it exposes the wire and shorts will send your car into limp mode. My advice is to check behind your wheel and see if the wire is hanging down, and if it isn't check to see if it's frayed (perhaps it was dangling before but not from the last install). If it is the sensor it's about $40 to replace.

The wire comes out of the wheel well cladding, attaches to the holes in the strut (with the clip) and leads into the brake.

ybKiDzO.jpg


Z5mxHZ4.jpg
Click to expand...

That's a good point. When I changed the suspension, the abs sensor snaps had been damaged. We'll take a look at this when we get our car back.

Thanks,
 
I'd also wager that the wheel size has nothing to do with your problem. Think of it this way, all the CX-5's use a doughnut (temporary smaller wheel/tire) as a spare tire. That spare is not the same size as the standard wheel. If different wheel sizes put the car into limp mode, every time someone changed a flat the car would stop working normally? That just does not make sense to me.
 
Even if the spare is a lot narrower, I think it is very similar to the diameter of stock tires and will have a similar revolution per mile result so if it turns at the same rate the car systems will not know the difference. Also it is very clear in the directions that you only put the spare on the rear of the car even if you have to rotate a tire to do that so that braking will not be overly affected.
 
GAXIBM said:
Even if the spare is a lot narrower, I think it is very similar to the diameter of stock tires and will have a similar revolution per mile result so if it turns at the same rate the car systems will not know the difference. Also it is very clear in the directions that you only put the spare on the rear of the car even if you have to rotate a tire to do that so that braking will not be overly affected.
Click to expand...

I did see that the manual says to put the spare in the back, but we're not talking about braking here, we're talking about the vehicle shutting down.

Also FYI, you are incorrect about the spare. My car is fitted with 225/55R/19's , the spare tire is 145/90/16. The difference in diameter is -8.4%, circumference -8.6%, 35.6% width.This is according to the tire size calculator located here: http://tire-size-conversion.com/tire-size-calculator/






The differences in diameter and circumference are pretty large considering only 1 tire will be a 16, and the rest 19's. Also this difference is larger than the numbers posted by the OP for his replacement wheels. So again, if tire size was an issue, putting on a spare would cause the car to fault. Which does not seem like a sensible decision by a manufacturer. I can see the lawsuits already, "I got a flat in the desert, changed it to the spare, then the car faulted and shut down, causing my puppy to die of heat stroke in the stranded vehicle"...(no puppies were actually hurt in this imaginary scenario). But you get my point.
 
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I said similar not exact. Your picture shows the inflation pressure to be 42 on the spare vs. 36 for the 19s. This should reduce the 8% difference in the calculated revolutions/mile and make the spare turn closer to the stock 19s. I agree that other than a possible tire pressure light the car should not shut down and go to limp mode with the spare on. Maybe other owners who have run the spare can speak up to indicate there experience with this.
 
Dumb topic. I'm curious if the OP figured out what the issue actually was?
 
GAXIBM said:
I said similar not exact. Your picture shows the inflation pressure to be 42 on the spare vs. 36 for the 19s. This should reduce the 8% difference in the calculated revolutions/mile and make the spare turn closer to the stock 19s. I agree that other than a possible tire pressure light the car should not shut down and go to limp mode with the spare on. Maybe other owners who have run the spare can speak up to indicate there experience with this.
Click to expand...

If you can show me some facts on that (pressure vs size) I'd like to see that. As far as I've seen, the tire sizes on the sidewalls are based on the factory recommended pressure. So why would using those pressures result in a different (effective) size tire than indicated?

Also to me, 1.5" (8.4% difference) in diameter is not "similar", that's a lot in my book.
 
See Indirect TPMS at https://en.wikipedia.org/wiki/Tire-pressure_monitoring_system
"First generation iTPMS systems are based on the principle that under-inflated tires have a slightly smaller diameter (and hence higher angular velocity) than a correctly inflated one."
Or see http://www.1010tires.com/About/Air-Pressure-Tire-Monitoring-System-TPMS
"The under-inflated tire is determined because of a higher angular velocity of its slightly smaller diameter."

The effective radius of the tire for angular velocity is the distance from the tire center to the ground. Taken to the extreme, think of a flat tire, it will only move ahead by the radius of the wheel, not the radius of the attached flat tire.
 
GAXIBM said:
See Indirect TPMS at https://en.wikipedia.org/wiki/Tire-pressure_monitoring_system
"First generation iTPMS systems are based on the principle that under-inflated tires have a slightly smaller diameter (and hence higher angular velocity) than a correctly inflated one."
Or see http://www.1010tires.com/About/Air-Pressure-Tire-Monitoring-System-TPMS
"The under-inflated tire is determined because of a higher angular velocity of its slightly smaller diameter."

The effective radius of the tire for angular velocity is the distance from the tire center to the ground. Taken to the extreme, think of a flat tire, it will only move ahead by the radius of the wheel, not the radius of the attached flat tire.
Click to expand...

Inflating a tire to a higher pressure will never result in an 8% increase in circumference!
 
Chris_Top_Her said:
Dumb topic. I'm curious if the OP figured out what the issue actually was?
Click to expand...

Not yet. The car was left at the dealer all weekend due to the holiday. Did the issue of the abs sensor affect you? If so, did you have any dash lights come on? We are going to call tomorrow morning to replace the abs sensors if they are damaged or loose for the fronts. I'm even more convinced (pissed) that it's not the wheels. It couldn't possibly be!

Thanks,
 
It can trip limp mode. At the least, if the wire touches something and it is frayed, it will put the abs, awd and other "wheel" lights on.
 
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