2014 VW Jetta Hybrid - Does not always start, sets CEL and EPC light on dash

Question

Greetings all,

2014 VW Jetta Hybrid Push to start, buried key, used THAR - VW1 w/EVO-ALL. Checked connections 4 times over, no issues with wiring, I can affirm this vehemently. Vehicle attempts to start, fails randomly. EPC and CEL lights will illuminate on dashboard, DTC P0703 will set for a circuit malfunction. Correct pin and wire color are tapped, as I have checked this vehemently. If you push your foot on the brake and remote start, the DTC will still set. If you start the vehicle normally, the DTC will NOT set, even with everything connected the same.

The vehicle will also NOT retry starting once the ignition is on, I'm not sure why this is. It will just sit there for 15 minutes with the ignition on, but no engine on.

When this concern initially appeared, I rolled the firmware back a version and this fixed the issue temporarily. I let the vehicle rest overnight and the issue returned next day.
Does anyone have any info on this? Please let me know, thank you.

Answer 1

Please enable diesel mode to delay the signal sent to the brake circuit, enable option D1.3

 

Vehicle is also in hybrid mode, vehicle is responsible for controlling the gas engine starting and stopping. It may stay on battery power only if voltage is high enough.

Comments

Found the fix as I will note above; Hybrid models seem to have a different pedal switch monitoring by the vehicle's ECU. This is due to the use of regenerative brakes, I assume. I disabled brake input monitoring and enabled stop with door open instead. Added a diode to the brake wire and the issue disappeared. I spoke with other installers of Fortin products, and apparently back-feeding/noise introduction is a known, yet uncommon issue with the EVO-ALL (I cannot confirm this as I am not familiar with the systems yet, as I normally use IDL, however with the recent price hike of hundreds of dollars on their systems, Fortin is a much better buy).

As for the intermittent no-start, this is also fixed with the diode, it has started every time since then.

Answer 2

Added diode to brake-send wire, vehicle no longer set DTCs and operated normally. Vehicle also starts every time with addition of diode. 

Diode used; Littelfuse 02400104P in a universal ATM fuse holder.