View Full Version : Cr0401/Cr0403 Unintended Output Energization

08-16-2016, 01:04 PM
I’ve discovered an issue with the outputs on the basic controllers (both Cr0401 & Cr0403) that’s resulting in the unintended cranking of an engine when power is assumed to be disconnected from the controller. I've simulated my customers setup & here’s what I’m seeing, which I’ve tested on both controllers:

N2-GND, P/N1-VBB1 &VBB2 are wired to the same connector.
N2-VBBs is wired direct to +VDC, not through the connector.
OUT0 connected direct to automotive relay terminal 86. Relay terminal 85 connected direct to –V.
These are the only things connected to the controller.

When I disconnect the connector, disconnecting +V from VBB1 & VBB2 & -V from N2-GND, but leaving +V on n2-VBBs, the controllers power off, but the relay is energized by OUT0. In fact all outputs on the controllers measure 12VDC to –V. I know this is due to leakage current, but it’s enough to fire the relay. I was under the impression that VBB1 & VBB2 were what supplied power to the respective output groups. I didn’t realize that there’s some kind of tie in with VBBS.

Jeremy Kopicz
08-17-2016, 01:47 PM
Why are you disconnecting the ground? If you pull the whole connector instead of just cutting power to vbbs i am guessing some strange things could happen. You are correct though, the outputs are powered from VBB1 and 2. There may be some capacitance left in the controller when you are disconnecting the connector.

08-18-2016, 09:21 AM
The problem was discovered when an end user disconnected the Deutsch connector in the field & the engine unexpectedly cranked. Don't know why the supply +V & -V were run through separate connectors allowing this to happen. I've already suggested that this be changed so that both VBBs & GND run through the same connector.

I think it's more than just capacitance though. During office testing the output, & attached relay, stayed energized for at least 15-20 seconds before I turned supply power off.