When you first got the module, did you connect this particular pump to the module or did you connect a different pump to the module. The module calibrates itself to the very first pump connected to it.
Please do the following:
1. Disconnect the power, pump and apex from the module.
2. Power up the module by itself and let it run through the cycle
3. Wait until the module errors out and gives you a red flashing light (takes about 30 seconds)
3. Power down the module and then connect the pump
4. Power up the module and the pump (don't connect to the apex yet) and the module will re-calibrate itself with the current pump.
See if that helps.