2003 electric ezgo diagnostic code 4-2 mechanical blockage

[hog372001]

When I push the accelerator the cart motor just knocks as if it's trying to move. I have new batteries and selonoid. When I jumper the motor terminals and apply voltage, the motor will work. I did disconnect the wires 1st. I have good voltage reading on the controller points of contact. Im wondering if it's the speed sensor. Any help is appreciated

[JohnnieB]

Sounds like you have a 2003 PDS. (Run/Tow switch on controller cover)

Push cart by hand and verify it moves freely.

If so, connect your DVM between the B- and A1 terminal on the controller and monitor the voltage.
When you push the pedal just far enough for the solenoid to click, you should have full battery pack voltage. (38.2V if fully charged)

If so, slowly press the pedal to the floor and the voltage should decrease to Zero.

Let us know what you get and we'll go from there.

Note: Before solenoid click, you will have about 3V to 5V less than full battery pack voltage.

[hog372001]

The cart does move freely when pushed.

I had 2.5V less on A.1 before I pushed pedal.

When pedal is pushed the voltage drops to 0 while it's attempting to move and then it's back up to the normal voltage on A.1.

[cgtech]

Check from controller B- to solenoid terminal "from solenoid to controller B+" when pedal is pressed.

[JohnnieB]

Originally Posted by hog372001

1. The cart does move freely when pushed.

2. I had 2.5V less on A.1 before I pushed pedal.

3. When pedal is pushed the voltage drops to 0 while it's attempting to move and then it's back up to the normal voltage on A.1.

1.
2.

3. Does the voltage drop to zero and then climb back up while pedal is still on floor?

As CG suggested, measure between B- and B+ terminals on controller.
What does voltage drop to when pedal is pushed?

[hog372001]

Yes, it climbed back up. I'll have to check the other terminals when I get off work

[hog372001]

It goes down about 5.5V at B- and it doesn't change on B+

[JohnnieB]

Originally Posted by hog372001

It goes down about 5.5V at B- and it doesn't change on B+

To get the above voltage readings, where were your voltmeter negative and positive test leads connected????

The voltage reading asked for was between B- and B+ terminals on the controller. (IE: Connect voltmeter's negative test lead to controller's B- terminal and connect voltmeter's positive test lead to controller's B+ terminal.)

[hog372001]

It goes down by about 5V and comes comes right back up when the pedal is fully pushed

[JohnnieB]

Sounds like the motor is sensing a high current flow through the motor, but not sensing the motor turning.

A bad speed sensor might be a contributing factor, but it is not alone. If the controller doesn't receive RPM data from the speed sensor, the cart will still move, It'll only move slowly, but it will move, so there is something else involved.

Check for worn insulation on F1/F2 wires.

Check the desired and undesired motor resistance. (I know it turns when you connect power directly to it, but an excessive buildup of carbon dust might be allowing a lot of amps to bypass the windings)