(Solved) Persistent P2420 code (and rare P0441) with no aux fuel tank. (3 Viewers)

[mcmarshing]

I think I figured out the problem. One of the male copper parts in the harness broke off inside of the female part of harness. Looked at EWD and it's the "VGND" that connects pump module to ECM.

See second from left, bottom row.

MK1 connector on EWD

MK1

Black wire.

Anybody know what's the best way to figure out the PN for this harness? I'm not seeing an "MK1" in chapter L of the EWD.
*edit* I think it's 90980-12380 and 90980-12379. Hopefully the pins are included?

 

[mcmarshing]

Still working EVAP issues. For whatever reason, the vent valve still is stuck off (in venting mode) but it does move when directly applying 12V to VLVB (+) and VGND (-) to the charcoal canister itself.

I spoke too soon. Did a continuity check on VGND (black) and there's a break somewhere in the harness. Just ordered a whole new harness (82163-60421) for that whole rear area. If anybody knows the P/N's of the little pop-in-ziptie parts back there, please let me know.

 

[mcmarshing]

Looks like I solved the issue. Drove 3000mi over the holidays and had zero CEL/MIL light. Ultimately the problem was a break in the VGND (black) wire caused by corrosion secondary to water/dust intrusion into floor wiring harness #3.

One thing I did notice when I got the replacement harness is that the superseding part number for floor wiring harness #3 (82163-60421) does not work with older 200 series. I think it has to do with small differences in the charcoal canister between the years, but both where the wires are in the harness and the overall length of wiring made it incompatible with my 2009 model.

82163-60420 on the right, 82163-60421 on the left. Notice how the female black end is longer on the older model going past the trailer control harness.

 

[StephenChelly]

Looks like I solved the issue. Drove 3000mi over the holidays and had zero CEL/MIL light. Ultimately the problem was a break in the VGND (black) wire caused by corrosion secondary to water/dust intrusion into floor wiring harness #3.

One thing I did notice when I got the replacement harness is that the superseding part number for floor wiring harness #3 (82163-60421) does not work with older 200 series. I think it has to do with small differences in the charcoal canister between the years, but both where the wires are in the harness and the overall length of wiring made it incompatible with my 2009 model.

View attachment 3812499
82163-60420 on the right, 82163-60421 on the left. Notice how the female black end is longer on the older model going past the trailer control harness.

View attachment 3812500

@mcmarshing This is super helpful, I have an 09 with a harness issue as well I believe. In your pictures, you show a broken male pin from the white connector. Looks like the harness you purchased handles the female side of that connection but how did you repair the male end that broke? That side of the harness goes through a grommet up into the body and looks to be quite extensive. I'm hoping you were able to buy a replacement pin or something along those lines for the male side. Much appreciated!

 

[mcmarshing]

@StephenChelly yes i did replace that one pin. I wish i had a PN for that for you but i don't... I just went to the local Toyota parts counter to ask for a male pin piece for said harness (MK3), and they had a PN for pigtails (male pins already crimped onto a 6" or so long piece of wire) for MK3, and they also had just the male terminal crimping piece on hand. I just got the male terminal crimping piece and just crimped it back on. i'm not gonna lie, it was a PITA to crimp a wire way up against the body, but it got done.

 

[StephenChelly]

@StephenChelly yes i did replace that one pin. I wish i had a PN for that for you but i don't... I just went to the local Toyota parts counter to ask for a male pin piece for said harness (MK3), and they had a PN for pigtails (male pins already crimped onto a 6" or so long piece of wire) for MK3, and they also had just the male terminal crimping piece on hand. I just got the male terminal crimping piece and just crimped it back on. i'm not gonna lie, it was a PITA to crimp a wire way up against the body, but it got done.

Ahh, that makes sense. Mine is the same issue, just a different wire in the same connector. I've had multiple different codes, mostly P0453, now P2420. Listing those for other who may run into the same. I replaced the gas cap, vsvs, the leak detection module on the CC with the pump, vapor sensor, etc. Mine acts up more in the wet/rainy winter months. I think that connector gets corroded being behind the rear tires. I appreciate you posting up your solution, looks like I'll be digging in this weekend, pending the dealer has the pins.

 

[prharper]

My P2420 came back a few days ago. Reset and then it was back again this AM.

Didn't get this code since Oct 5, 2024.

I'm still thinking it's wiring harness related. Forgot to add the harness to my Serra Decatur parts orders during the last sale.
FWIW - (edit - have not ordered yet but according to my VIN check ) > wiring harness #3 82163-60421 does not fit my 2018 LC. This one does 82163-60500. (Will order). I already have a new charcoal canister in a box.
If I'm going to drop the LRA, I'm only doing it once and want the harness on hand just in case.

 

[gasman4u]

My P2420 came back a few days ago. Reset and then it was back again this AM.

Didn't get this code since Oct 5, 2024.

I'm still think it's wiring harness related. Forgot to add the harness to my Serra Decatur parts orders during the last sale.
FWIW - wiring harness #3 82163-60421 does not fit my 2018 LC. This one does 82163-60500. I already have a new charcoal canister in a box.
If I'm going to drop the LRA, I'm only doing it once and want the harness on hand just in case.

Good call on having what you need for your plan to be executed. My LRA ultimately had to have the harness extended due to ham fisted attempts at botched repairs previous to the shop that actually knew what they were doing. The shop that ultimately got rid of my CEL replaced the connector bit iirc. Thanks for posting the accurate part number too - hopefully it helps those who follow.