2004 Dodge Caravan - 1/1 O2 PO132

[mopwrforme]

Well I'm finally going to say it; HELP!

At this point if I were still at the chrysler dealer, I would be calling the hotline to talk to the guys who created this system. But being on my own, that's not an option. I'm stuck with this fine piece of metal; its not a comeback, its an 'I won't leave".

Anyway, first time around I swagged it with an new aftermarket O2. After installation, the O2 heater checked good; it warmed up correctly, pwm correctly, the o2 was switching good. I let it cool down, then on test drive it drove fine. I next checked it for 1 trip failures to find the code had returned. Also with no heater at all, 0 duty cycle O2 stuck rich.

Checked the wiring and found high resistance in the return wire, so at this point I ran temp. new wires from the pcm to the O2 connector a new signal, return, as well as a new O2 control wire, I also ran a new wire for the ground, straight to the ground post of the battery. Replaced the O2 with a new factory O2 (#56029052aa), reset pcm. This time it took approx. 3 restarts and it returned just as before; no O2 heater p0132 so I'm now thinking okay, pcm driver must have fried from the bad wire. Okay replaced the pcm with a factory pcm reprogrammed correctly still to have the same issue.

I'm stumped; new pcm, new O2, new wiring, no pushed pins, no high resistance, also with the new pcm i put in, another new factory O2. So let's see; that makes 3 O2 sensors, a pcm, new wires; what am i missing? At this point, I'm out to lunch.

[mopwrforme]

just an update after going over the flow chart with the new pcm and doing some cking i found the new right out of the box factory pcm was only putting out 9.4v to the heater grid. this should be a 12v pwm signal that maintains correct o2 temp. in 05 they went to a 12v none pwm o2 heater that requires a updated o2 with a [heavyduty] heatergrid.along with a software undate, its been my understanding whenever an electrical device doesnt get the proper volts and amps it tends to not work correctly. so i have returned the new pcm and am awaiting its replacment hopefully with a better outcome. thanks to all

[Tim Martin]

As an experienced driveability tech, I share your frustration with situations like this. I been doing this for 17 years and have seen similar times when the situation defies logic. My usual proceedure when I get to a point like this is: 1. Take a break. 2. Begin diagnostice anew by starting diagnostics with basics including battery. 3. Review results with what has been done so far and compare.

Having said that, I have had similar times already when an aftermarket electronic part has ruined an otherwise good PCM. It may be that is what happened here. An, as murphy's law would dictate, ya get a bad PCM. My suggestion? Install replacement PCM, and begin diags all over. About all ya can do at this point. As a side point: i have seen stray voltage and other electrical signals interfere with some a these wiring situations. Can't rule that out.

hth

[steven kiser]

have one in the shop right now with electrical issues. found the harness had melted together under the battery. was talking to the parts manager at the dealer we purchase our chrystler parts from and he said that they see wiring issues on these from time to time. hope this helps.

[mopwrforme]

just an update the new pcm was on target it started at 11.5v on the heater grid then backed off a little talking too the chrysler hotline i found out the pcm will back off the driver if it thinks there is an open hinc the instruction to ck the circut with a test light to grd. it should blink brightly. when actuating the 1/1 heater grid with that and installing a new 1/1 o2 from the factory the system worked correctly. with an extended test drive i retested the 1/1 o2 with no 1 trip failures or codes i delivered it to the customer today. my other issue is what too charge for the repair. it wasnt his issue i had parts problems and a bunch of extra time involved. i ended up charging 2.0 lab and only marked up the pcm $20.00. i lost my ----- and the customer is a little miffed. due too the time but i thought it was fair. bye the way thanks to everyone

[steven kiser]

isn't it fun taking it up the breezeway. we all have these situations. your right, it's not the customers fault and they shouldn't be held responsible for it. there are times when we blow through a job and make a good buck and feel guilty that it went so smooth and feel like you're over charging. it all works out in the end. i let the customer know what i went through just so they know. some feel that they need to pay more and others thank me for being so fair. you've developed a good relationship with your customer. that's what's important here. you've joined the ever shrinking group of honest mechanics. welcome aboard. enough said............