Can you also post a picture of the X13795 brown wire grounding point?

 

Multimeter said open loop, however it also spiked to a pretty high value occasionally, but otherwise consistently said open loop.

Quote:

Originally Posted by Maybe, maybe not

Also measure the fuel pump connector power pin voltage using X13795 as the ground.

With the ignition on (no brake pedal), it read 7V.

 

I'm going to pack it in for tonight. If you want, you can post the next step and I'll get to it tomorrow morning

 

Does a nut or bolt secure the ground wire to the body? If so, remove the nut/bolt and inspect the wire terminal and bolt. If you see any corrosion or tarnishing, clean with wire brush or sand paper. Reinstall the connection and redo voltage test to see if voltage reading rises above 7V or comes close to 12V.

If the voltage reading does not change, then the wire between the grounding point and the fuel pump connector may be damaged.

Good luck. I'll recheck your thread tomorrow.

 

The X13795 ground connection serves as a grounding point for all of these functions:

• Center brake light
• Fuel pump
• Outside fold-in mirror
• Rear window defogger, left
• Taillight, left
• Tire pressure controle module
• Utility socket, rear
• Boot lid push button/license plate light

If the fuel pump is the only listed function that doesn't work, then removing and cleaning the X13795 ground connection (see my post above) may not be worthwhile, and the problem most likely is the brown ground wire or its connection at the fuel pump connector.

Afterthought: I'm perplexed by the fact that the seat belt bolt ground allowed you to detect ~12V on the fuel pump power pin while the X13795 ground point did not. Might be worth repeating both voltage measurements.

 

I cleaned all points of contact with that grounding point with sandpaper, though nothing appeared corroded. I also checked the wire terminals on the ground post side and they looked fine as far as I could see. I measured voltage again and still got only 7V. This tells me that it might be the wire itself, which I'm dreading because I have no idea how I'm supposed to get to that...

 

I redid it on the seat belt bolt and got 7V this time. Not sure why I got something higher earlier. Maybe I moved the connector into the exact right spot for it to read a healthy voltage haha

 

The brown wire problem may be inside the fuel pump connector. Do you see any access for de-pinning the brown wire from the connector? Any visible damage to or corrosion on the connector ground pin?

 

For diagnostic purposes, consider cutting the brown ground wire several inches away from the fuel pump connector. To locate which segment of the wire has the high resistance, use your multimeter to compare resistance readings between (1) the cut point and the fuel pump connector ground pin and (2) the cut point and the X13795 ground point.

 

OBDII port pins 6 & 14 communicate with the JBE via the D-CAN network. After you have fixed the fuel pump issue, you may want to check for abnormal voltage readings on the yellow/black and yellow/brown D-CAN wires.

 

I don't see any way to de-pin that wire. I've stripped back some of the tape and removed the rubber seal, but that's as far as I've been able to get. Hard to tell if it looks corroded if I can't pull it out

 

Is there any chance that this AI response provides helpful guidance for de-pinning the fuel connector?

 

I did this and actually got a result! The ground on the connector side reads open loop like before, however the ground on the chassis side was reading an actual resistance (it was all over the place because it's a stranded wire and I'm not that steady)

 

Nice work! Makes sense together with your other test results. Now you can focus on figuring out how to depin the brown wire from connector. Proceed slowly and carefully.

 

This honestly looks fine to me. I don't see anything wrong with the connection

 

Again, you are amazingly fast! What information do resistance measurements provide about where the fault lies in the removed wire?

 

When I measure resistance connected to two sides of the exposed wire I get a fairly high value. However when I measure one side on the exposed wire and the other side on the pin I get a much lower value

 

Odd result. Do I see significant wire insulation damage and potential bulging of the wire due to corrosion adjacent to the connector pin?

 

That might've actually been my fault when I used too aggressive of a tool to pull the wire out (before I saw the AI response). I have more stranded copper wire I can put in place of that if need be

Edit: Though I just used a pair of pliers lightly, so I don't feel like the damage you see there entirely lines up with what I did

 

Side note: You should soon repeat your voltage measurement of the fuel pump power pin using the segment of wire with the X13795 ground point to see if you now get a 12V reading.

 

You should now consider carefully de-crimping the connector pin and recrimping it to a good segment of wire. Then, repeat the resistance measurements to verify low end to end wire resistance.

 

I de-crimped the connector, which took a bit, and then got it onto a new piece of wire with similar resistance readings to the ground wire hooked up to the chassis. Then I spliced those two wires together and heat-shrunk them, but I'm still getting the same low voltage reading, even after all that. Is it possible it's the connector itself?

 

Did you voltage test the segment of wire with the X13795 ground point before splicing?

 

No, I forgot to do that honestly. Did you want me to put the positive side into the power connector and the negative side on the X13795 ground wire?

 

You learn much more by voltage testing the fuel pump power pin using the entire segment of wire with the X13795 ground point to see if you get a 12V reading.

Strip away some brown wire insulation to allow good contact with the black meter probe.