Limp Mode

[WejaZ28]

I Have a 08' PDS cart, with 36v, with Curtis Controller, and stock tires. I picked it up up a few months ago. Cart is used for cruises around the golf course in the evening. There are a few large hills to climb. Cart ran great for about a month, up to 18mph(Freedom plug). One ride I had the power shut off going up a hill(like batteries died). Shut everything off waited a minute and cart ran fine. This became an intermittent thing for a while.

This has now progressed to starting off in limp mode every time I stop. Switching off the key makes it run normal until the next time I stop.

Note: I have added a rear seat and have carried as many as 6 from time to
time. It has also gotten hot hear in AZ.

I pulled a 3-2 code from diagnostics.
Solenoid tested good.

Tested Controller, Measured voltage at all pins specified in test. got just under(high 37v) base voltage(38.4v) on all pins tested except white wire at J-3 (about 33v)

Tested Run/tow switch and did not get continuity on the white wire. Other side was good?

Tested voltage from A1 to B- after solenoid click and got just under base voltage(37.9v). pressed pedal to floor and got 18v, not 0v?

J1 pins 4 and 5 get full voltage.

Checked ITS sensor and Got 14v at the white wire?

Checked voltage after solenoid click at J4 pin-3 and B-, got 1.06v

Batteries are a year old.

I've read every thread on limp mode and anything else pertaining to power loss on this site. I've conducted as many diagnostic tests that seem relevant so far. This is a lot of information to assimilate, but I'm game.

I'm hoping that you guys can walk me through this issue.

I have a few possible ideas but would like to here from some of the experts here before I throw more money at it for something that was easily fixed.

Thanks for reading the book, Kevin

[JohnnieB]

The 3-2 error code means the Voltage on the controllers B+ terminal is not equal to the voltage on J1 Pin-5 when the solenoid contacts are closed, or slightly less when solenoid contacts are open. If the Pin-5 voltage matches pack voltage and there is no voltage drop across the cable from solenoid to controller, then the solenoid contacts are likely burnt.

B- to A1 not going all the way down to 0V is normal if you have the rear tires spinning in the air. (The controller is going to RPM limit the motor by throttling back.) Slowly apply the brakes to slow the rear wheels down some and the voltage ought to drop lower.

The other cause of not going all the way down to 0V is the ITS input. Attached is how to check ITS input to controller. Looks like you did 2 of the 3 tests and the voltages were withing specs, now you just need to check J4 Pin-3 with pedal down.

I suspect all you need is a solenoid or maybe a cable to get cart running, however with a rear seat and carry six, it'd be a good idea to think about doing some upgrades.

The first thing I did when I got my 2998 PDS in 2011 was replaced all ten of the high amp cables with 2Ga and got a noticeable (seat of the pants) improvement in torque. Speed stayed the same due to the controller RPM limiting the motor.

If you want more speed, upgrade to an Alltrax XCT48400-Pds controller and it will do about 24MPH on stock height (18") tires with a 36V battery pack.

Going to 42V will up both speed and torque by 16% and 48V will up both by 33%.

[WejaZ28]

Made best effort to make sure cart was in limp mode each test. So I started by doing the 3 ITS tests.
All done with key on, in "F", base battery pack voltage 38.5+/- and 36.60v across solenoid contacts open.
Done according to diagrams:
1) pin-4 J4. B- to Pin-4(White wire) -5.35v
2) Pin-3 J4. B- to Pin-3(Black wire) 37.13v Pedal pressed just to click.
3) Pin-3 J4. B- to Pin-3(Black wire) 35.08v pedal to floor

B+ and J1 Pin-5 both 38.25v but dropping as I watched. Contacts closed
Pin-5 voltage matched pack voltage. no drop across cable from solenoid to controller(36.47).
Contacts open B+ 20v and Pin 5 38.35v. (20v seems to be the limp mode limit)

B- to A1 started at 20v and never went below 18v not matter how hard I applied brakes. key off, voltage went up to 36.50v

After original post, I switched another solenoid in cart and it still went into limp mode immediately, so I switched the old one back in.

You never mentioned the low voltage white wire and non continuity at the run/tow switch? Not that its related but seems a bit odd.

It is my intention to upgrade the solenoid controller and wires after sorting this out. No plans to go to 48v. happy with 36v.

The reference to 14v at white wire was done at the pedal assembly in the floor and at J4 Pin-4 plug. This was done by conducting the ITS sensor testing from manual page that's posted here.

Hope makes sense. Thanks

[JohnnieB]

In your first post, you got 14V on J4 Pin-4 and 1.06V on J4 Pin-3 (Pedal up?), yet in your last post you get -5.35V on J4 Pin-4 and close to pack voltage on J4 Pin-3 with pedal up and down.

Suggest repeating the ITS voltage check with DVM's negative lead on either the controller's or the battery pack's B- terminal.

-------------
I missed the no continuity on the Run/tow switch. When in Run, there ought to be full battery pack voltage on all four pins of J3.

Attached is a drawing showing the control voltage paths through the PDS controller and a picture with Pin-1 highlighted on all the jacks.

[WejaZ28]

Could be because cart is going in and out of limp mode on me.

I will run tests again...

[WejaZ28]

Ok, reran ITS tests again...

Test 1 14.62v
Test 2 1.06v
Test 3 2.81v

Sorry, it was a long day (yada yada yada).

[WejaZ28]

And J3 has 38.2v on all but white wire. It is 31.4v

[WejaZ28]

Ran the B- to A1 test again.
If it stays out of limp mode i get 37v and it goes down around zero at full pedal.
When it slips into limp mode, I get 20 volts and does not drop below 1q8v at full pedal.

[WejaZ28]

that's 18v above

[JohnnieB]

Originally Posted by WejaZ28

And J3 has 38.2v on all but white wire. It is 31.4v

Unfortunately, the wire colors on the EZGO schematics and drawings I have for J3 do not match the colors of wires on your Run/Tow switch, or mine.

Fortunately, I have a picture of the stock PDS controller that was in my cart originally and it appears the wire colors on the J3 plug are as follows:
Pin-1 = Red
Pin-2 = White
Pin-3 = Orange
Pin-4 = Yellow

If so, the white wire is on Pin-2, which is the Aux. voltage returning to the controller from the Run/Tow switch. This voltage starts at the solenoid's battery side large terminal, enters controller on J1 Pin-5. exits on J3 Pin1 to Run/Tow. Sounds like you've got a bad Run/Tow switch. (That might be causing the 3-2 error code - which is putting cart into limp mode)



Try connecting the Red wire and white Wire on the same switch terminal. That should eliminate the switch contacts. (Unplug J3 while making the changes - same as putting Run/Tow in Tow)