Disconnecting PCM connectors

[DavidEBSmith]

A while back I was getting codes P1633 (Keep alive memory voltage low) and P0449 (Canister vent valve circuit malfunction) and tracked it down to no voltage getting from the battery to the connector on the PCM. I installed a jumper wire from the battery to the wire that leads to the PCM and the codes went away, for about a year.

Now I'm getting P1633 again but not P0449. The 12V jumper is still supplying voltage. I suspect that it's feeding back downstream to the canister vent valve, so that is working and not throwing a code, but that the 12V is not getting into the PCM. The wire on the harness between the jumper and the PCM connector looks like there's some corrosion, so I suspect there might be corrosion on the pin inside the connector.

Is removing and reconnecting the PCM connector as simple as flipping the lever, pulling off the connector, and putting it back together?

I remember some bad experiences in electronics days past with connectors with delicate pins that if you didn't get everything lined up properly, it was really easy to bend pins and cause even bigger problems. Hoping automotive connectors intended for auto mechanics would not be so delicate.

 

[AZExploder]

it is that simple. Just be very careful to not bend any pins when re-inserting. Look for corrosion or discolored pins .

 

[Doraemon0825]

A while back I was getting codes P1633 (Keep alive memory voltage low) and P0449 (Canister vent valve circuit malfunction) and tracked it down to no voltage getting from the battery to the connector on the PCM. I installed a jumper wire from the battery to the wire that leads to the PCM and the codes went away, for about a year.

Now I'm getting P1633 again but not P0449. The 12V jumper is still supplying voltage. I suspect that it's feeding back downstream to the canister vent valve, so that is working and not throwing a code, but that the 12V is not getting into the PCM. The wire on the harness between the jumper and the PCM connector looks like there's some corrosion, so I suspect there might be corrosion on the pin inside the connector.

Is removing and reconnecting the PCM connector as simple as flipping the lever, pulling off the connector, and putting it back together?

I remember some bad experiences in electronics days past with connectors with delicate pins that if you didn't get everything lined up properly, it was really easy to bend pins and cause even bigger problems. Hoping automotive connectors intended for auto mechanics would not be so delicate.

Hi where is the pcm location?

 

[Bazz270]

Passenger side firewall

 

[DavidEBSmith]

Since this has resurfaced - the wire broke off right at the back of the connector, too close to be able to splice a wire to it. The proper way to fix this would be to remove & replace the contact in the connector with a new longer wire attached.

I found this thread Pins in Wiring Harness on PCM connector that shows you how to take the connector apart and remove the contact.

I finally did pull the connector off. It was very reluctant to come off plus it's the middle connector so it's awkward to get a grip on. Before I messed with taking the connector apart to fix the contact, I decided to make sure I could get the connector back on the PCM. That was also hard - the force it took felt like it was too much to not be breaking something. I took a straight pin and slipped it into the back of the connector hole where the broken wire was, attached that to the jumper wire, and the truck started AND the CEL stayed off, no codes. I suspect there must have been some internal corrosion that got scraped away from removing and replacing the connector.

Anyway, immediately took it to the smog check before the straight pin could come loose and it passed and I have another 2 years to fix it right. The guy congratulated me on having a vehicle that passed with 231K miles.