DCS ITS - weird reading

[JeremyH]

Hi everyone. Still working on a weird issue with a 97 EZGO TXT 36v.

New motor (stock),new batteries, new Alltrax XCT48400-DCS controller (original was a Curtis 73144G03).

When I power up, I get a 2R/5G error light sequence (low throttle input overrange). I called Alltrax support and we went through a few things and the only way we could get the solenoid to click and spin the motor was to set the throttle control in the Alltrax Toolkit to USB control and do manual override. If we set it to the EZGO DCS ITS throttle setting I get nothing.


I threw the VM on the white & black wires coming out of the controller and recorded the following:

Black & White wires @controller (disconnected from the ITS): 10.36v
Black & White wires @ ITS (disconnected from the ITS): 10.36v


I then reconnected the B&W wires to the ITS and I'm seeing the following @Controller and @ITS:

Black & White wires connected to ITS - No throttle: 7.33v
Black & White wires connected to ITS - Full throttle: 3.86v

From what I've read, it should go from about 10v to 6v when you go from 0 to 100% on the throttle. What gets me is how it drops as soon as the ICS is connected. I checked the gap on the plunger and adjusted it to the 7/64 when open (it was almost 1/4 initially).

I've replaced the ITS with another and I get the same results. Do I have the wrong controller? Wrong throttle setup?

[JohnnieB]

The ITS sensor draws more amps (Milli-amps actually) and Alltrax uses a constant current source to feed it, so to keep the amp flow the same, the applied voltage is reduced when the sensor tries to draw more amps.

Since your ITS voltage readings are lower than specs with pedal up or down, my guess is there is a partial sort between the black and white wires.

The typical culprit is the inline connector at the end of the gray cable coming out of the pedal box. Replace the in-line connector with four individual butt splices or solder joints, covered with marine grade (adhesive filled) shrink tubing.

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As for the controller being set to correct throttle type (EZGO ITS), throttle type set to is on one of the Toolkit screens. While controller is connected to computer, the LED flashes four times, pause then repeats, if set to EZGO ITS.

Also, when controller powers up, LED flashes four time than goes top steady green.

[JeremyH]

So I went and cut off the molex connector for the B/W/R/G cable and soldered and shrinked each connection. Same result. I get 10v at the plug by the controller. 10v at the other end by the ITS (unplugged from the ITS).

As soon as I plug the into the ITS, it drops back to that 7v setting.

I'm about ready to push this SOB off a cliff.

[JohnnieB]

Have you verified EZGO ITS throttle type is selected?
Have you cleared the throttle auto-cal?
Have you measured resistance between Black and White wires when they are disconnected from ITS sensor and from controller?
Have you tried a new ITS sensor, or was the replacement another used one?
Have you tried drying the used ITS sensor with a hair drier?

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The ITS sensor has some electronic inside it and does strange things when moisture (humidity) gets inside. The senor is potted for waterproofing, but the potting compound shrinks with age and hairline cracks develop, allowing moisture to get to the electronics. (Block diagram and Schematic of ITS sensor attached)

[JeremyH]

Have you verified EZGO ITS throttle type is selected? - Verified

Have you cleared the throttle auto-cal? -Not entirely sure how to clear that

Have you measured resistance between Black and White wires when they are disconnected from ITS sensor and from controller? - showing 0 ohms when disconnected

Have you tried a new ITS sensor, or was the replacement another used one? - replacement was a new ITS sensor

Have you tried drying the used ITS sensor with a hair drier? both have been clean/dry since the beginning

What's interesting is the stock ITS setup shows 100% throttle as soon as you key on (see attachment).

[JohnnieB]

Originally Posted by JeremyH

1. Have you verified EZGO ITS throttle type is selected? - Verified

2. Have you cleared the throttle auto-cal? -Not entirely sure how to clear that

3. Have you measured resistance between Black and White wires when they are disconnected from ITS sensor and from controller? - showing 0 ohms when disconnected

4. Have you tried a new ITS sensor, or was the replacement another used one? - replacement was a new ITS sensor

5. Have you tried drying the used ITS sensor with a hair drier? both have been clean/dry since the beginning

6. What's interesting is the stock ITS setup shows 100% throttle as soon as you key on (see attachment).

1.

2. Clear Auto-cal is on a drop down menu - see attach-1 Or use Absolute throttle, explained in Toolkit manual. ---- But first address issue(s) in 3. below.

3. Any resistance BETWEEN those two wires is in parallel with the ITS sensor and can lower the voltage out of the normal 10V up / 6V down range.

4.

5. Something can look dry on the outside and be damp on the inside, especially in humid areas, but a new sensor shouldn't have any hairline cracks in the potting compound, so it is likely to be dry on the inside.

6. Note the double headed arrow (<->) under the translucent throttle marker. That means the green shaded area grows larger to the right as throttle % increases. The graph you posted is showing <1%. A better place to see the throttle % is on the monitor screen, it show it both as a bar graph and a numeric value. (attach-2 is the monitor screen someone with a XCT48400-DCS posted, Throttle is top left gauge)

[JeremyH]

JohnnieB - first off, thanks for the help/guidance/suggestions.

I went and reset the auto-cal on the throttle.

I even tried temporarily running two new wires from the cut at the molex (before I soldered the OEM wire/connections) to the ITS with the same results. As soon as either ITS is plugged in, it goes south.

When I key on the controller, the throttle goes right to 100%

[JohnnieB]

Pop the 10-pin connector off the XCT-DCS controller and measure between pins 1 & 2 (Black and white wires) with an ohmmeter while the ITS sensor is disconnected from the other end.

It should read infinity (Open). Any ohm reading whatsoever, other than Overload ( or whatever your DMM uses for infinity), is going to cause the ITS voltage to be lower the the 10V it is supposed to be.

If those two wire a totally isolated from each other and you have tried two ITS sensors with the same results, chances are extremely high the controller is bad and it is time to get on the horn with the vendor and Alltrax for a warranty replacement.

[JohnnieB]

Just took a quick read of the earlier posts in this thread. I missed a couple tests needed to prove controller is bad.

What is the voltage on Pin-9 and Pin-10? Both ought to be FULL battery pack voltage.

[JeremyH]

unplugged 10 pin harness
- Pin 9 - 37.5v
- Pin 10 - 37.5v
- B+ & B- (direct on battery pack) - 37.5

with harness unplugged and ITS unplugged took my VM set to OHMS

red probe in pin1 (white wire), black probe in other end of white wire: 000.0
red probe in pin2 (black wire), black probe in other end of black wire: 000.0