PDS runs rough ends up in limp (safe) mode

[mdrgolf]

I spent the last two evenings reading tons of threads in this forum and have learned alot (thanks JohnnieB, and others), but I haven't been able to find a matching problem.

Here are the particulars. I am not sure what is relevant and what might not be relevant, so I will include as many details as I can.

It started with my 2002 TXT PDS that I bought in 2005 (all stock equipment), occasionally coming to a full, hard stop as i was trying to coast to a stop. Almost like a certain slow speed triggers a an auto brake. And it is not a gentle auto brake,

Next, i started noticing the motor "missing" a little while at full throttle. By missing a little it almost felt like very slight turbulence in an airplane. Or maybe like a car that was slightly missing on one cylinder. You really had to be paying attention to feel it, but it was consistent. It would run at full speed then for a split second slow down a very little bit then go right back up to full speed. I ran the cart like this for several rounds, thinking it was so slight that it might correct itself.

Then slight missing then turned into an occasional hard bump. Almost like the cart lost power for one second out of every 10.

When the hard bumps started, I checked all cables and the only anomaly I found was the cable that runs from the negative terminal of the last battery to the controller was extremely hot. Checked the cable and the fitting was bad. Replaced the cable and went ahead and put in a new solenoid since i was opening up the controller cover anyway. The cable replacement cured the heat problem, but did not change the "missing", the hard misses, and the occasional auto stop when coasting.

After reading the forums and realizing how important the controller beep codes are, I am sorry to report that the F/R buzzer was apparently disconnected by the previous owner. So I don't have any codes to report. (I would like to figure out how to fix the buzzer, but I guess that is for another day).

So yesterday i charged the 2016 Trojan batteries. This morning I took the following voltage readings:
6.37 Volts
6.37 Volts
6.35 Volts
6.35 Volts
6.35 Volts
6.33 Volts
Pack Voltage 38.12

I took the cart for a drive.
Ran like a jackrabbit when i started down the driveway. As i coasted do a very slight hill at the end of the driveway, the auto brake kicked in and the cart skidded to a stop. The the auto brake released and the I mashed the accelerator and the cart ran great for about 50 yards, then started the occasional slight "missing". Another 150 yards and the cart starting the really rough missing. Another 100 yards and the cart was limping along in safe mode.

Limped back to the garage and took the following battery readings
6.31 Volts
6.33 Volts
6.31 Volts
6.30 Volts
6.30 Volts
6.30 Volts
Pack Voltage 37.86 Volts

I am hoping someone might suggest some tests that might pinpoint the problem(s) with my cart.

Thanks in advance.
Mdrgolf

[Timberwolflt]

The slight “missing” at full speed is probably the controller limiting max rpms of the motor... probably the fuller the charge... the more noticeable it is

I’m betting on a go pedal issue... or could be an intermittently bad connection on any one of the connector pins... my PDS does the same thing but not to a severe degree... If I want to deactivate the regen brake... which I love love love... I just crack the throttle a little more
I love my regen brake so much... I’ve ruined my mechanical brake cables because I never use em

The experts should be along shortly

[JohnnieB]

Intermittent problems are very difficult to troubleshoot since they can only be found diagnostically while they exist, so the first step is to fix the beeper and maybe putting the controller into diagnostic mode will give us a hint where to look.

The beeper is located on the driver's side of the passenger glove box. Typically, somebody just reaches under the front cowl and pull off whichever wire they lay their fingers on. You'll probably be able to see it looking under the cowl with a flashlight and might be able to reconnect the wire (push on spade connector).

If not, remove the keyswitch - F/r switch panel to gain access to it.

The text at the bottom of the attached PDS label tells you how to put controller into diagnostic mode.

Also, what mode plug (speed chip) is in J2?

[mdrgolf]

Thanks for the replies guys.
I’ll work on restoring that beeper

[Timberwolflt]

You could also pop out the cup holder to get to that buzzer

[mdrgolf]

I got my buzzer working. Just like you said JohnnieB, the previous owner had simply unplugged it. Had to take the key switch out to access it.
My fault code is 1-3 for the speed sensor.
I also must note that after a 3 mile ride around the hood that the new solenoid is pretty hot to the touch. I have no idea if the old one got hot. Cart is all stock with the performance chip.
I haven’t researched what to do about the speed sensor yet.

Cart can get me around the course the course okay when it’s not in diagnostic mode.
Do I risk further problems driving it to play golf with a speed senor fault and a hot solenoid?

Also any tips on speed sensors would be greatly appreciated.

[JohnnieB]

Since the problem is intermittent, or at least started out as such, I suspect the magnet disk on the end of the motor shaft is loose, but it might be a loose connection.

First unplug J5, spray clean and reconnect. Attachment-1 is an image of controller with jacks labeled. If that isn't it check magnetic disk for tightness.

Attachment-2 is an exploded view of the speed sensor, magnet disk, outer & inner snap rings and screw. You'll have to remove the outer snap ring and speed sensor to tighten the screw holding the magnetic disk.


------------
Running at low speed allows the motor to draw a lot of amps, which in turn generates a lot of heat, so you might burn out a solenoid and motor if you run the cart a lot before it is fixed.

[mdrgolf]

Thank you so much JohnnieB. I owe you steak.

[cgtech]

Man this guy is good. What exactly was the problem/fix? (For those in the future with this problem).

[mdrgolf]

No fix yet. Cleaned J5.
Magnet was tight.
Gonna check accelerator pedal electronics next.