Like many DIY car enthusiasts, I’ve used the Obd2 Jumper method to pull diagnostic codes on my 2008 Honda Element. When my transmission “D” indicator started blinking, I knew it was time to check for trouble codes. Using online forums like the Element Owners Club, I found guides explaining how to use a jumper wire on the OBD2 port to retrieve these codes, specifically mentioning bridging pins 4 and 9.
Having done this on other vehicles before, the process seemed straightforward. However, in my slightly awkward position under the dash, I misidentified the pin layout on the OBD2 port. Instead of correctly jumpering pins 4 and 9, I mistakenly connected pins 5 and 16. It wasn’t until later, referencing a common OBD2 pinout diagram, that I realized my error: I had inadvertently jumpered pin #16, the +12V battery supply, to pin #5, the signal ground. Essentially, I created a short circuit within the OBD2 port.
OBD2 Port Correct Jumper Pins
Initially unaware of my mistake, I corrected the jumper to the intended pins 4 and 9. Success! I retrieved a transmission code (26, indicating a faulty 3rd clutch oil pressure switch). Pleased with this diagnosis, I went to start my Honda Element, only to discover a range of electrical accessories were no longer functioning. It became clear that my brief OBD2 jumper mishap, shorting the 12V supply to ground, had caused unexpected electrical problems.
Despite checking all the usual fuse locations, I haven’t found any blown fuses. The electrical issues are puzzling because some systems are still working perfectly, while others are completely dead.
Here’s a breakdown of what’s working and what’s not:
Working Systems:
- External lights (headlights, taillights, turn signals, backup lights)
- Rear hatch dome light
- 12V Accessory socket in the passenger dash
- Power windows
- Power mirrors
Non-Working Systems:
- Radio
- Dome light (only works when the key is in the ON position)
- Power door locks (partially working – details below)
- Remote keyfob (no functions)
- Cruise control main switch (button near driver’s knee does not illuminate)
- OBD2 port itself (no power on pin #16, scanner cannot connect)
The power door lock behavior is particularly strange:
- Key ON: Unlock button on the door panel works for all doors, but the Lock button does not function. Manually pushing down the lock knob on the driver’s door locks all doors.
- Key OFF: Neither Lock nor Unlock buttons on the door panel work. Manually pushing the lock knob on the driver’s door only affects that door, not the others.
These symptoms bear a striking resemblance to an old forum post I found (https://community.cartalk.com/t/2004-honda-element-no-power-to-radio/92269) describing similar radio and power lock issues in a 2004 Honda Element. Unfortunately, that thread lacks a definitive solution.
If shorting the OBD2 port’s 12V supply to ground is indeed the culprit, where should I investigate next? Are there any less obvious fuse locations or perhaps a relay that might have been affected? Does anyone have access to a wiring diagram for a 2008 Honda Element that could help pinpoint the affected circuits? Any guidance on troubleshooting this electrical mystery after my OBD2 jumper mistake would be greatly appreciated.
