2000 Caravan P0132 AND P0138

I will read the ECT and air temp on scan tool when I go back out in a few minutes. It's cold so I'll take notes. I'm not sure where the backfire is happening; I can't make it happen in park, only in drive. It seems like it is coming from the exhaust, and sounds like a "boomph" but there's no way I can listen more precisely while in gear and moving. I have not checked the plugs or coil; I have new plugs but was putting off their replacement because of the extreme disassembly required. It's now highest on my priority list. I tried to check the fuel pressure at 2krpm but the gasket inside the adapter was shredded and I can't get a reading. I've got to return the tool and get the gasket replaced or buy a tool to run that test again. I'll watch the map data and try the map sensor tomorrow morning. I'm still trying to figure out how to take a screenshot of the scan data. If it comes down to it, I'll take a screenshot of the gauges and dials on my scan tool's display; I'm using a bluetooth adapter and an Android app for this. Thank you so much for your help, Dodgefarms!

OK engine coolant temp behaves as expected. Fan turns on at about 220F. Couldn't find an air temp PID in my app; gonna hunt around in the book and see if there's a sensor. Meanwhile, I got a new pressure tester and hooked it up. I'm getting about 58-60psi at idle, fluctuating widely from about 45-60 when the idle is laggy and rough (around 450rpm). At 2k rpm and above, no difference. It stays steady at 58-60rpm. Then, I shut the engine off and wandered away for about 15min. When I came back the pressure had dropped to 44psi. Just went and checked again, its down to 30psi. I'm gonna make sure its not the tool; some fuel sprayed out the pressure relief switch when I first pressed it to depressurize before testing. If that's not leaking, sounds like an injector might be.

>OK engine coolant temp behaves as expected. Fan turns on at about 220F. Couldn't find an air temp PID in my app; gonna hunt around in the book and see if there's a sensor. >Then, I shut the engine off and wandered away for about 15min. When I came back the pressure had dropped to 44psi. Ck again, could be injector leaking or bleeding back into the fuel tank via fuel pump. Had more than a few of these vans with worn out spark plugs and bad coil packs, so ck that. Did you ever unplug the MAP sensor? and create a vacuum leak and see if O2 sensors come down, or do O2 sensors voltage go down or start switching at 2000 rpms?

Ok I got into a check the injectors for leaks thing, and ended up taking out the intake plenum a few days ago. Pressure tested the rails with all the injectors sitting on a piece of cardboard. Couldn't find a leak. Cleaned, inspected, and replaced the injector o-rings. Replaced the spark plugs and wires, coil, and reassembled. Tested the injectors with the old "unplug one and see if the idle drops" and it sure does, X6 cylinders. Also used a noid light on each injector cable. They all seem good. I cleaned out the throttle plate area, double checked the TPS sensor by unplugging it; when not mounted on the throttle body it goes from 3-97%, .20-4.6Vdc I cleaned and inspected the IAS; it's got a bit of carbon on it but not too bad, and it appears to be working: when cold, when the A/C is used, and when the throttle is dropped from WOT. I tried unplugging the MAP sensor and (not at the same time) several different vaccuum hoses. I don't have a vacuum tester so I couldn't go in depth, and I don't fully understand the vacuum system in this vehicle yet so I'm not sure what exactly to look for. Each time I unplugged something the performance degraded and there's definitely suction everywhere. I still have not been able to get the O2 sensor voltage to go down, not even at 2k rpm. So the main problem still exists: both O2 sensors start at .5 volts, start and idle the upstream one starts climbing, it takes about 30 seconds to get to 1.27v and then the downstream one does the same, climbing from .5 to 1.27vdc in about 30 seconds. Performance is shoddy especially cold or when briefly cooled from a hot running state. Backfiring (I think) out the exhaust but it's possible it's backfiring out the intake; I can only get it to backfire when in gear and moving. After parking and shutting down the engine, it takes about 3-5 minutes for the downstream O2 sensor to start dropping down to .5v and then once it does the upstream one does as well. I'm guessing that's because atmosphere is slowly mixing into the exhaust system. Is it possible that my new computer was programmed incorrectly? This started when I replaced it; before the computer replacement there was no degraded performance and no faulty O2 sensor circuit error. IF there *IS* a problem with the computer? Who can help me? Do I have to take it to a dealership or can smaller shops generally get into it at a deeper level than I can?

>Is it possible that my new computer was programmed incorrectly? This started when I replaced it; before the computer replacement there was no degraded performance and no faulty O2 sensor circuit error. This could be the problem. Sorry I forgot to ask, but I thought you had same problem before new PCM. Dealer or send it to ECM website dude. I had 800 number I got once of magazine and he did a good job, but I haven't dealt with him in about 2 yrs. This may be it, but I'm not sure (make sure you get federal emissions or whatever you have). http://www.ecmdepot.com/ No misfires? You check for strong steady spark from coil pack? Try dropping exhaust to ck for clogged cat? Ck intake air to air filter housing for debris, and by unplugging MAP sensor I mean just unplug wire, don't remove sensor.

I got the part from these guys: http://yhst-21854666697846.stores.yahoo.net/info.html I checked for strong steady spark, replaced the coil pack just for giggles, and checked again. It's all good. The intake pathway is clean and has a new filter (one of the first things I did of course.) I have not re-checked the exhaust since dropping it to put in the upstream O2 sensor.

Sure looks like the PCM is at fault. You could check the voltage coming from the PCM with DVOM on each bank with 02 disconnected. If faulty bank 1 does not have same biased voltage from PCM as bank 2, then it's the PCM or wire. Make a warranty request and see if they will honor it, or have more info.

Are you referring to O2 sensor bank 1 and 2? There's 2 sensors on bank 1 and 0 sensors on bank 2. I guess I'm just not sure precisely what you're referring to. I have contacted them by email and am waiting for a reply. Meanwhile I will disassemble the exhaust system on Wednesday and make sure that there are no restrictions to flow, and test whether the O2 sensors work correctly with the catalytic converter detached (they didn't last time I checked but I'm not opposed to double- and triple-checking my work when I troubleshoot.) At this point I have disassembled, cleaned, inspected, tested, and replaced nearly all of the air, fuel, spark, and exhaust systems. There does still appear to be a genuine rich mixture condition.

I stand corrected, this vehicle only has one o2 upstream and 1 downstream. [edit] Last ck the G101 ground wire on the back of engine, transmission side.

Ok exhaust is good. Sensors are putting out between 100 and 200mv when operating, as measured at the sensor and at the PCM. Apparently the PCM is reading that as 1.27v. Contacted the warranty department supervisor and he's cross-shipping me a replacement.

Make sure you have no vacuum leak. Some Chrysler 02 sensors go from 1-5 volts. Not 0-1 volt. But if your code is right, then it's probably the PCM.

Yup pretty sure according to everything I've read, anything over 900mv for 2 minutes or more will set the code. So, I could have solved this a lot faster if I'd been more meticulous about following your instructions, Dodgefarms. Thank you also for the block diagram you sent, that showed me which pins to probe on the PCM connector (C1-30 for upstream, and C2-51 for downstream). The wire colors even matched what my Haynes said. Now to wait for the replacement PCM and see if that fixes the problem and/or causes a new one. Thanks again for all your help!

Welcome, would could have easily assumed that since codes did not happen with old PCM that it was PCM, but best to do all you can to check - at least we tried

Well the old PCM was already failing to get ANY sensors "ready" P0601 code so I couldn't even tell before if any of the sensors were working or not.

Yes, 600 codes are bad news.

HELLO! i know i am late but i am just wondering if there was a resolution to this? read entire thread, and curious as to what happened afterwards... reading all of this feels too close to home (my truck has been having issues very similar to this guy's caravan). MAIN difference is that before i had the p0132 error code, I had a code for System Too Lean. i replaced both sensors, first the post-catalyst sensor, then the pre-catalyst (upstream) sensor, and now ended up with the p0132. Still in the early troubleshooting process, so is why i was curious to find out if the issue was resolved for the caravan in this thread. thank you --david

DizzyFranco digging up the dead - years old and likely a different issue from you. You had a LEAN issue what code ? Why did you change o2 sensors? Did you repair the lean issue? Hopefully you used dodge part (NTK) and NOT a wire yourself aftermarket type, aftermarket o2 sensors are problematic. Do you have a scanner or just key on off trick?

I have same issue. I had the p0601 swapped pcm with one from the junkyard amd now 0132 and 0138 Plymouth grand voyager se 3.3l so same motor was doing way better for a couple days with the new pcm now usually on warm starts im getting sputtering amd no power not so much on cold starts. I think ill try to go have the pcm flashed can most dealers do this amd is it a cheap service