Cart only goes 5mph

[Jonathan08]

New Cart owner here. I just purchased a 2001 Ezgo 36 Volt Txt PDS golf cart. It will not go faster than 5mph (possibly limp mode). All batteries are new and have been checked on load and get good readings. We ran the diagnostic on the cart and we get a 3-2 beep which is a “Welded Solenoid”. We replaced the solenoid and the speed sensor. No change in cart performance still stuck going 5mph. The “jumper” wire (not sure what it is called, the 250 ohms wire) that goes onto the large posts of the solenoid has blown. A regular jumper wire is in its place until I can get a new wire ordered. We tested the A1 and 2 wires as well as the F1 and 2 wires on the motor. Here are the results of those tests.
A1: No Load 22.7 Volts A1: Under load 7.1 Volts.
A2: No Load 23.0 Volts A2: Under Load 20.0 Volts.
F1: No Load 1.4 Volts F1: Under load 3.3 Volts.
F2: No Load 1.4 Volts F2: Under Load 4.2 Volts
Obviously the number that jumps off the page is the A1 Under Load Volts dropping to 7.1.
We have checked and replaced all we know how to at this point. Is it possible that the A1 wire is bad and it shows up Under Load? Do you think it is a bad controller? Bad motor? Or something else we don’t know about or haven’t tried. We are open to all suggestions. Thank you for any help.

[BobBoyce]

Originally Posted by Jonathan08

New Cart owner here. I just purchased a 2001 Ezgo 36 Volt Txt PDS golf cart. It will not go faster than 5mph (possibly limp mode). All batteries are new and have been checked on load and get good readings. We ran the diagnostic on the cart and we get a 3-2 beep which is a “Welded Solenoid”. We replaced the solenoid and the speed sensor. No change in cart performance still stuck going 5mph. The “jumper” wire (not sure what it is called, the 250 ohms wire) that goes onto the large posts of the solenoid has blown. A regular jumper wire is in its place until I can get a new wire ordered. We tested the A1 and 2 wires as well as the F1 and 2 wires on the motor. Here are the results of those tests.
A1: No Load 22.7 Volts A1: Under load 7.1 Volts.
A2: No Load 23.0 Volts A2: Under Load 20.0 Volts.
F1: No Load 1.4 Volts F1: Under load 3.3 Volts.
F2: No Load 1.4 Volts F2: Under Load 4.2 Volts
Obviously the number that jumps off the page is the A1 Under Load Volts dropping to 7.1.
We have checked and replaced all we know how to at this point. Is it possible that the A1 wire is bad and it shows up Under Load? Do you think it is a bad controller? Bad motor? Or something else we don’t know about or haven’t tried. We are open to all suggestions. Thank you for any help.

Where the jumper wire is should be a precharge resistor. Having a jumper wire will give you the Welded Solenoid error you are getting. That error might explain why your controller is cutting back on power and reducing the maximum power being fed to your motor.

[Jonathan08]

Thanks Bob. I hope you are right. I will order one ASAP.

[Jonathan08]

Ok so I removed the jumper wire and put on a 250 ohm resistor. That cleared the 3-2 code. But now the cart won’t run at all and I am getting a 3-1 code which says “Solenoid driver fail” “Vehocle will not run” “ “Check coil wiring for shorts, replace controller”. We put in a new solenoid so if the “coil wiring” it is referring to is in the solenoid then I think that’s good. Does anyone have any other suggestions short of replacing the controller? Thanks again.

[thehole]

I had a similar issue. Cart ran fine, then all of a sudden it wouldn't go fast at all. My problem turned out to be a cracked speed sensor magnet. Bought a new one from Amazon for $11. It was a very easy and quick fix. There's a motor which is easily accessible by removing the left rear wheel. You'll see 3 wires go into this motor, remove 2 screws, and the housing has this little donut shaped magnet in it. Mine had a crack, so I replaced it, and now it's fine.
Hope this does the trick.
Gary

[Jonathan08]

Thanks for the idea Gary. We already replaced the speed sensor and yes it was a quick process. But it didn’t fix our problem. We now think the problem lies in the controller. We are going to run a bench test on the controller and see what results we get before we order a new controller.

[BobBoyce]

If it were me, I would let the throttle microswitch activate a small 48 volt relay, like an IDEC RH1B-U DC48V General Purpose Relay that could control the negative to the solenoid. It has 10 Amp contacts that could carry the solenoid activation current with no problem. The pedal box already switches +48V, just connect the pedal microswitch output wire to the relay coil positive. Hook the negative of the IDEC relay coil to pack negative and to the Common contact connection, then run a wire from the Normally Open contact to the negative side of the solenoid. That would get rid of the welded solenoid error, and activate the solenoid instead of the controller doing it. You could probably use it for years that way, as long as the controller is operating normally otherwise. Be sure to keep the controllers solenoid activation wire connected to the negative side of the solenoid so that the controller senses the solenoid activation. I just can't see wasting an otherwise workable controller. Unless Alltrax feels generous enough to replace the controller under warranty? It's worth a try

[Jonathan08]

That unfortunatly is above my head. I’m not sure what all that means. Hahaha Sorry. I’m sure it would help to be able to do it.

[Jonathan08]

Update. I just ran a controller bench test. Found a bad Solenoid driver. All other tests came back good. Does anyone thinks it’s worth having the controller rebuilt? Or should I just get a new one?

[JohnnieB]

Originally Posted by Jonathan08

Update. I just ran a controller bench test. Found a bad Solenoid driver. All other tests came back good. Does anyone thinks it’s worth having the controller rebuilt? Or should I just get a new one?

Replace it with an Alltrax XCT48400-PDS or larger.