[maddog2020]

My guess is you have a missing ground strap somewhere. The P0403 is less likely to be that issue, more likely a vacuum leak, but all those others smack of grounding issues. Check the ground cable that runs from the end of the O2 sensor harness to the body ground on the firewall by the passenger footwell.

Ian

 

[maddog2020]

One other thing - make sure you take it through the full drive cycle. Disconnect the battery for a bit, then after reconnecting do this: https://smogcheckvacaville.com/chrysler-drive-cycle-odb2-readiness-monitors/

 

[maddog2020]

Thanks - that's a great link. But step one is to make sure the MIL is out. I can't get it to clear. I don't know why - my scanner would clear it in the past but now it just says DONE when I erase the codes, but it doesn't really do anything.

Anyway, I'll check the grounds. I replaced the straps that go from the engine to the hood and firewall (that wacky "Y" type of strap) when I replaced the engine. I'm not sure all of those codes are real - I think they're artifacts from doing a key-on with the PCM's C3 connector unplugged (part of the P0403 diagnostic procedure).

I may have to take it somewhere that has a real scanner to clear the codes. Mine's just a cheap Actron unit. In the meantime we're driving it all over the place to try to get the conditions right for the monitors to run.

Any scanner can clear codes. Plus, if you disconnect the battery for a couple of mins that'll clear any codes too. It's more likely they're all coming back on straight away.

There's a ground from the body to one of the screws on the PCM, but the key one to look for is at the end of the O2 Connector circuit to the body ground on the firewall under the heat shield on the passenger footwell. In the process of reconnecting mine I also grounded the motor to the body, oddly enough it doesn't seem to normally be grounded together. Anyway, here's what I did: https://www.wranglerforum.com/f202/o2-sensor-heater-issue-solved-2286810.html

You might want to not do the motor to body ground as there are probably reasons why that isn't normally present.

Ian

 

[maddog2020]

Oh yeah - and the P0403 says it's an electrical circuit malfunction but I'm intrigued by your comment on a vacuum leak. There's no vacuum port on the EGR. Is it looking for a change in vacuum when it commands the EGR on or off? If so, where is it getting that measurement from? MAP?

The only reason I mentioned vacuum issue is that when I replaced my intake manifold gasket I failed to the get the EGR pipe bolted back to the valve cover properly and it threw some EGR codes.

Ian

 

[maddog2020]

That helps. It's odd because it's been fine for a year - just the P0403 code. I went through the diagnostics for the P0403 and now I have all these other codes. I'll double check all of the grounds though - I may have disturbed something.

The factory braided grounds on the passenger side were broken. I replaced them with the correct MOPAR part (it took forever for them to find the right one). It goes from the block to the hood and the firewall. I'll have to look but I thought there was also a pretty fat ground on the stud in your picture - maybe the battery? I'll have to check later when the Jeep returns home.

You mean the one circled in yellow? That's on the bottom passenger side of the engine block, there are two things connected to that:

1 - the ground that comes out of the end of the O2 sensor harness (this is supposed to be grounded to the body ground in the second picture, but I couldn't get it off the ground on the block).

2 - the new strap I put in that connects the block ground to the body ground.

Ian

 

[maddog2020]

So I put jumper cables from the battery to the PCM and from the engine to the chassis. Then it let me clear the codes. I unhooked the cables and started it up. The P0403 came back immediately but none of the others. The P0403 is an electrical malfunction.

My GF has been driving it and she said the low tire indicator, hot light and oil pressure light popped on and off at random times over the past few days. I'm thinking it's all related and probably grounds. I'll have to look at it closer.

Good idea as a way to test it.


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