roadkill401 Posted January 19, 2015 Report Share Posted January 19, 2015 I just noticed that the speed that the speedometer says I am going, is not the same as the displayed cruse speed on the secondary display to the left. So if I take my Edge up to 60km on the speedometer, and turn on cruse and hit SET, the secondary display to the left shows that I am in cruse at 62km/h. But the speedometer says I am only going 60. So I slow the cruse down to 60, and the speedometer now says I am going at 58km/h. So I speed myself up to 70 on the speedometer, and reset the cruse. It shows 68km/h Sort of get the feeling that the two systems are set at different speeds. Now they should be getting the EXACT same information from the wheels. I know that the temp gagues I was told are off because of a rounding issue from the sensor and they are running on two different systems. But I would think that there is ZERO room for rounding error when it comes to speed. And 2km/h is a rather big rounding error. The vehicle is going in to the dealer tomorrow for other issues of the GPS getting lost. The rear mirror wobbling, the Sync entertainment system randomly turning itself on or changing channels with no user input. I will have to see what excuse they give for this one. Under warranty I expect it to work perfectly 100% of the time or they will need to keep fixing it. Quote Link to comment Share on other sites More sharing options...
WWWPerfA_ZN0W Posted January 19, 2015 Report Share Posted January 19, 2015 Hopefully it just requires a new battery/ PCM reset to fix all these issues. I WILL note that the speed displayed on my Edge's analog gauge and the Toque Pro app are often up to 2 mph apart! Quote Link to comment Share on other sites More sharing options...
akirby Posted January 19, 2015 Report Share Posted January 19, 2015 That's a normal variation. It's impossible to get the analog needle calibrated perfectly on every vehicle. Ford errs on the side of the speedo showing a faster speed than actual which is safer than if it showed a slower speed. But it's normal. 1 Quote Link to comment Share on other sites More sharing options...
omar302 Posted January 19, 2015 Report Share Posted January 19, 2015 On my MKX, the cruise set speed & the Speedo match exactly. My guess would be a calibration/software update required. As for akirby's comment regarding the speedo showing a faster speed, you are dead on. This can be confirmed using a GPS, but you can also see that it is actually made in the programming of the cluster, if you enter the engineering/test mode in the cluster, you can see the raw speed displayed which is very close to the GPS reading & higher than the speedometer/cruise speed. Entering the Engineering/Test menu: http://www.explorerforum.com/forums/showpost.php?p=3086315&postcount=2 1 Quote Link to comment Share on other sites More sharing options...
WWWPerfA_ZN0W Posted January 19, 2015 Report Share Posted January 19, 2015 For 2010 & older Edge, I think, you might be able to enter the Engineering Menu in the IPC this way: http://www.fordedgeforum.com/topic/7844-engineering-mode-gauges/?do=findComment&comment=62222 1 Quote Link to comment Share on other sites More sharing options...
roadkill401 Posted January 19, 2015 Author Report Share Posted January 19, 2015 In my case if you look at it, the speedometer is slower. So if I am driving with the speed displayed by the speedometer, then I would be travelling faster than I think that I am. This puts me in the liability side of getting a speeding ticket for driving too fast. And the point of people saying an Analog gague is a bit of a misnomer as the whole of the interface pannel is completely digital driven. The dial itself does not get driven by a turning wire but it plugged directly into a computer board. If the parts supplier cannot build a dial that can accurately turn to the correct position when the digital signal is sent for a specific number then they should be replaced by a better company. Quote Link to comment Share on other sites More sharing options...
TheWizard Posted January 19, 2015 Report Share Posted January 19, 2015 Actually no, the speedometer is analog. The ECM sends a square wave signal with pulses corresponding to the vehicle speed. Digital displays like the cruise have circuitry that count the pulses over a time span and calculate then display the corresponding speed - that is digital. But the speedometer needle is driven by a stepper motor that is basically an electromagnet that deflects the needle based on the average current flow through its coils - that's analog. Quote Link to comment Share on other sites More sharing options...
roadkill401 Posted January 19, 2015 Author Report Share Posted January 19, 2015 OK.. So with the Analog speedometer, if the fault was with the internals to it, one would expect that the error would be a percentage inaccuracy. So at 50km/h if the speed was off by 2, then at 100km/h it would be off by 4. But in my case, the error is exactly 2km/h slower on the speedometer compared to the cruse control at all speeds (that you can engage cruse). So either the speedometer marking were just painted wrong, or some other component is calculating inaccurately. In reality, it's just another one of those things that you just live with. But it's just another example of the BS they give us along the same lines that "We have to build to a longer life standard with it being a car". What they are infact saying to us is that they can build crap that doesn't work properly but it should last you forever. Quote Link to comment Share on other sites More sharing options...
akirby Posted January 19, 2015 Report Share Posted January 19, 2015 Other reports say that the displayed digital speed is actually 1-2 mph slower than actual speed and it's done on purpose for the reasons we just stated. So it's possible your speedometer is accurate with respect to actual speed and the digital display is lower. You can test it with a handheld GPS or do the old manual calculation using mile markers and a stopwatch. It could be a calibration issue with the speedo but it could also just be normal. It's not that they don't build crap properly and don't care - it's a complicated thing to sync up so many digital and analog devices AND don't forget they have to account for different tire diameters based on simple things like treadwear over time and inflation pressures not to mention people who replace their tires with a slightly different size. When you're a mfr building millions of cars per year you have to take all that into account. It's never as simple as some people like to make it. Quote Link to comment Share on other sites More sharing options...
TheWizard Posted January 19, 2015 Report Share Posted January 19, 2015 (edited) OK.. So with the Analog speedometer, if the fault was with the internals to it, one would expect that the error would be a percentage inaccuracy. So at 50km/h if the speed was off by 2, then at 100km/h it would be off by 4. But in my case, the error is exactly 2km/h slower on the speedometer compared to the cruse control at all speeds (that you can engage cruse). So either the speedometer marking were just painted wrong, or some other component is calculating inaccurately. When the difference is constant like that rather than being a percentage, it is unlikely to be a calibration issue. It is equally unlikely to be the stenciling of the markings on the face because of the way they are mass produced. The likely cause is that the needle is positioned on its shaft just a little bit out of position. In the old days, those needles used to be like axles - the needle and the shaft it fit onto were splined and could only be put together in a limited number of relative positions. But late model vehicles now mostly use press fit needles without any splines so it is possible for the needle to be out of position by quite small amounts. The cluster can be removed and the dust shield taken off so that the needle can be pulled and repositioned but having done so during installation of aftermarket gauge faces, I can tell you that it is a real pain to do so and can take many attempts to get the position just right. Personally I wouldn't go to that much trouble for a small difference but it is an option if you are so inclined. But first I would go with akirby's suggestion to check with a GPS and determine which display is actually wrong - the speedometer or the cruise setting. Edited January 19, 2015 by TheWizard 1 Quote Link to comment Share on other sites More sharing options...
WWWPerfA_ZN0W Posted January 19, 2015 Report Share Posted January 19, 2015 Well, I have the "opportunity" to put on new tires come this spring, let's see what happens then . Stock size of course! Quote Link to comment Share on other sites More sharing options...
akirby Posted January 19, 2015 Report Share Posted January 19, 2015 I just calculated that it can change by 1-2 mph over the life of your tire just due to treadwear alone. So it's never going to be more accurate than that. 1 Quote Link to comment Share on other sites More sharing options...
enigma-2 Posted January 19, 2015 Report Share Posted January 19, 2015 Akirby is right, there is a tolerance that the speedometer can read during normal operation. Here's what the service manual says about it. Pinpoint Test I: Inaccurate Speedometer Indication Normal Operation The PCM calculates the vehicle speed from the transaxle Output Shaft Speed (OSS) sensor input and from the tire size and axle ratio configuration in the PCM Vehicle Identification (VID) block. The PCM provides the Instrument Cluster (IC) with the vehicle speed data over the High Speed Controller Area Network (HS-CAN) bus. The IC monitors the vehicle speed input and commands the speedometer with a corresponding movement of the pointer. The IC provides a tolerance which biases the speed indication and allows the gauge to display between 3% lower and 7% higher than the actual vehicle speed. This means that with an actual vehicle speed of 96.6 km/h (60 mph), the speedometer may indicate between 93.7-103.3 km/h (58.2-64.2 mph). Other factors that can potentially affect the speedometer accuracy are incorrect tire size, tire size configuration and axle ratio configuration. If the IC does not receive the vehicle speed data from the PCM for 5 seconds or less, the IC defaults the speedometer to the last setting, based upon the last known good vehicle speed message. If the IC does not receive the vehicle speed data from the PCM for more than 5 seconds or if the data received is deemed invalid, the IC sets DTC U0100 in continuous memory and defaults the speedometer to 0 km/h (0 mph). NOTE: If DTC U0100 is set in the IC , other observable symptoms may be an inoperative tachometer, temperature gauge or odometer. One thing this brings to mind is having your PCM recalibrated after you do a tire size change. 1 Quote Link to comment Share on other sites More sharing options...
omar302 Posted December 7, 2015 Report Share Posted December 7, 2015 I know it has been nearly a year, but I just saw this & thought it might be relevant if the issue is still not resolved: Service Bulletin No.: 44856Component(s): VEHICLE SPEED CONTROL NHTSA ID Number: 10057831Manufacturer: Ford Motor CompanySUMMARY:FORD: CERTAIN 2013-2015 FORD FUSION AND TAURUS, 2011-2015 FORD EXPLORER, 2013-2014 FORD EDGE AND FLEX, 2013-2015 LINCOLN MKS, MKX, AND 2013-2014 LINCOLN MKT VEHICLES MAY EXPERIENCE PROBLEMS WITH THE CRUISE CONTROL SPEED THAT DOESN'T MATCH THE SPEEDOMETER SPEED. *TA 2 Quote Link to comment Share on other sites More sharing options...
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