Limp Mode Troubleshooting After Controller Installation

[Unicorn]

04 Club Car DS IQ. ADC Motor. I sent the Curtis 1510-5201 controller off to be rebuilt and upgraded to 400amps due to overheating errors and shut down. My cart ran 20mph when it was sent out and my speed sensor was working (beeping on rollaway). I installed the rebuilt controller but I am only running at 8mph in forward and reverse. Also my speed sensor stopped beeping on rollaway. I replaced the speed sensor to rule that out. No change. No beeping. I switched the magnet. No change. I don’t think my sensor or magnet is faulty. With the accelerator to the floor and back wheels elevated I am reading 48-50v at the b- and b+ controller terminals. I have an analog voltmeter so it’s not exact. This shows I have power to the controller right? If my speed sensor is good, my magnet is good, and the controller is getting power, does that mean the controller has an issue after being rebuilt? My Crown batteries are 6 months old. I’m running out of things to test. Everything worked perfectly except for the co troller before the limp mode. Installation was done with both positive and negative cables disconnected and reconnected correctly.

[Fairtax4me]

Normally those controllers need to be programmed prior to installation. Did they mention anything, or did you request any certain settings for speed or regen function?

[Unicorn]

Originally Posted by Fairtax4me

Normally those controllers need to be programmed prior to installation. Did they mention anything, or did you request any certain settings for speed or regen function?

It’s a known rebuilder. They said the speed code should be unaltered and still there. Even with a speed magnet. No change. It’s like it senses no speed sensor.

[Fairtax4me]

Ok, you should have a red wire, light green, and a black/white stripe wire going to the sensor. All three are next to each other on pins 15,14, and 13 at the controller.
Red is 5v out to the sensor, Light green is signal voltage back which varies from 0 to 4.5v roughly. Blk/white is negative for the sensor.
Check for 5v going to the sensor on the Red wire. Test at the sensor and at the controller. If no 5v, the controller is faulty or there is a bad connection or damaged terminal in the connector.

If 5v is present, check for the same on the Blk/White wire to make sure the negative is good. This should be 0v or close to it. If there is higher than 0voltage on the Blk/Wht wire there is a bad connection or damaged pins, or faulty controller.

If Blk/Wht wire has 0v then check speed sensor output on the Lt Green wire.
With on rear wheel off the ground probe the lt green wire and spin the wheel. The voltage should jump up an down (should be very easy to see with an analog meter) And range anywhere from about 2.5v up to maybe 4.5v at the highest.

If that is all good, the controller is faulty.

[Unicorn]

Originally Posted by Fairtax4me

Ok, you should have a red wire, light green, and a black/white stripe wire going to the sensor. All three are next to each other on pins 15,14, and 13 at the controller.
Red is 5v out to the sensor, Light green is signal voltage back which varies from 0 to 4.5v roughly. Blk/white is negative for the sensor.
Check for 5v going to the sensor on the Red wire. Test at the sensor and at the controller. If no 5v, the controller is faulty or there is a bad connection or damaged terminal in the connector.

If 5v is present, check for the same on the Blk/White wire to make sure the negative is good. This should be 0v or close to it. If there is higher than 0voltage on the Blk/Wht wire there is a bad connection or damaged pins, or faulty controller.

If Blk/Wht wire has 0v then check speed sensor output on the Lt Green wire.
With on rear wheel off the ground probe the lt green wire and spin the wheel. The voltage should jump up an down (should be very easy to see with an analog meter) And range anywhere from about 2.5v up to maybe 4.5v at the highest.

If that is all good, the controller is faulty.

I can do that. Question first is…if the only thing that changed since my speed sensor worked and I had 20mph was the controller being rebuilt pretty much mean the controller has an internal mistake/failure? I appreciate your help very much. This cart is garage kept. I can’t think of anything that would have altered the functionality and continuity of the wiring for the speed sensor.

[Fairtax4me]

It's always possible to have a broken wire, even on the best maintained vehicle. The wiring for the speed sensor is small, and it has to flex and move with the motor as the suspension of the cart moves. So it's worth it to check that the sensor is getting proper voltage, and if it is, that it's sending a signal back to the controller.

It's also entirely possible to get a controller that is faulty even though it has been "rebuilt". Maybe it worked fine on their bench, and there is some fault with a solder joint or something else in the controller that was aggravated by shipping.
FSIP does thousands of controllers every year, and it's always possible that a bad one slips through, despite their best efforts. If it is a problem with the controller, I have no doubt they'll take it back and send you another one.

[Unicorn]

Originally Posted by Fairtax4me

It's always possible to have a broken wire, even on the best maintained vehicle. The wiring for the speed sensor is small, and it has to flex and move with the motor as the suspension of the cart moves. So it's worth it to check that the sensor is getting proper voltage, and if it is, that it's sending a signal back to the controller.

It's also entirely possible to get a controller that is faulty even though it has been "rebuilt". Maybe it worked fine on their bench, and there is some fault with a solder joint or something else in the controller that was aggravated by shipping.
FSIP does thousands of controllers every year, and it's always possible that a bad one slips through, despite their best efforts. If it is a problem with the controller, I have no doubt they'll take it back and send you another one.

That’s my thought. Fully functioning before a rebuild. Not FSIP. If everything worked before I would guess it is an internal failure. I don’t see any broken wires and this cart has been untouched since removal.

[Reddawg454]

I'm with FairTax to check it before you condemn it but thats up to you. Spending a few minutes to confirm the speed sensor wiring is correct is pretty easy. Sending the controller back only to be told its good could take several weeks and make you look like the....... Just my opinion.

[Unicorn]

Originally Posted by Reddawg454

I'm with FairTax to check it before you condemn it but thats up to you. Spending a few minutes to confirm the speed sensor wiring is correct is pretty easy. Sending the controller back only to be told its good could take several weeks and make you look like the....... Just my opinion.

I can do that. Thanks guys. I’m guessing the speed sensor will only get power to test for with the cart in run and the accelerator pushed down correct? Then I can unclip the sensor connector near the motor and and test for voltage?

[greg-g]

Originally Posted by Fairtax4me

Ok, you should have a red wire, light green, and a black/white stripe wire going to the sensor. All three are next to each other on pins 15,14, and 13 at the controller.
Red is 5v out to the sensor, Light green is signal voltage back which varies from 0 to 4.5v roughly. Blk/white is negative for the sensor.
Check for 5v going to the sensor on the Red wire. Test at the sensor and at the controller. If no 5v, the controller is faulty or there is a bad connection or damaged terminal in the connector.

If 5v is present, check for the same on the Blk/White wire to make sure the negative is good. This should be 0v or close to it. If there is higher than 0voltage on the Blk/Wht wire there is a bad connection or damaged pins, or faulty controller.

If Blk/Wht wire has 0v then check speed sensor output on the Lt Green wire.
With on rear wheel off the ground probe the lt green wire and spin the wheel. The voltage should jump up an down (should be very easy to see with an analog meter) And range anywhere from about 2.5v up to maybe 4.5v at the highest.

If that is all good, the controller is faulty.

Couple of things good troubleshooting above the red and black wire from the speed sensor should have 15 volts not five there are two things that can cause limp mode speed sensor and solenoid also you should check the programming to make sure it wasn't reset to Speed code 1. One more item there's a lot of people the throw-in bigger mosfets and say they upgraded the controller but the seepex controllers need to be reprogrammed to use that and unless they change the field map you're not going to get any more current out of that controller.