2003 Dodge Dakota 4.7 H02 sensor control circuit

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I went to get my truck inspected this morning and it couldn't pass due to the following codes:

P0032: HO2S 11 heater control circuit high (bank 1 sensor 1)
P0038: HO2S 12 heater control circuit high (bank 2 sensor 1)
P0052: HO2s 21 Heater control circuit high (bank 1 sensor 2)

I had no idea it even had any codes because the CEL bulb was burned out. Lovely.

Any ideas? I find it had to believe all three of those sensors are bad. I did just replace a reverse sensor/switch in the trans that was shorted out, so I guess anything is possible.

I'm thinking either a wire is shorted out or the PCM is bad. I ordered a code scanner that can read voltage, etc. but that won't be here for a few days yet.

Any help would be much appreciated. Thanks.
 
I'd start by checking your wiring AND making sure you have clean, tight grounds.

With so many of them called out, make sure the engine and chassis grounds are good.

Do a visual inspection of the O2 sensor wiring as well. Is there a fuse for the heated O2 sensors? If so, check that as well.

I don't know how many miles on the sensors. It probably wouldn't hurt to swap the the bank 1 and bank 2 after cat sensors as only one of them is listed as faulty. If the fault follows the sensor, it's bad. If the fault remains on bank 1 sensor 2, it's likely an issue external to the sensor.

Of course, by the time you do the work to remove a sensor, you might want to simply replace it with a new one if the costs are not too high.
 
59k.

I checked under the hood for a blown fuse, the fuse was missing but it doesn't look like it connects to anything. Apparently the 4.7 doesn't have a fuse for the o2 sensor, only the 5.9.

Is there a way to test the sensors before replacing them?
 
Clear the codes and see if they all come back simultaneously or intermittently. If they come back, you can check the wires and plugs running to the sensors themselves for visible signs of damage (burned, etc.). Also check that the voltage is good at the plugs with a multi-meter, then the ground and resistance for each as well with the multi-meter.

The device you ordered will give you the read-outs of voltages from the sensors, but that should just reaffirm what the codes are telling you - the voltages are out of range. But the pattern of output from each can be used to verify the sensors are bad. Although it is unusual for so many to go bad at once I would think.

The fact that the CEL bulb was burned out and that you had another switch on the vehicle which had an electrical issue is probably not a coincidence. This could be an electrical gremlin which takes a lot of time and effort to ferret out unfortunately.
 
Codes for all the sensor heaters usually means there is no power supplied to that circuit. There is a fuse somewhere, it may have more than just the heaters on it.

The heater section of an O2 sensor can be tested with an ohmmeter. Do this only when they are fully cold.
 
It's weird, there's a fuse and a relay for o2 sensor, but there isn't any metal underneath them. They're just dummy holders, maybe a different powertrain combo used them but not this one.

I am going to wait until my code reader gets here so I can do some diagnosing with the voltage readouts. Either that or pay a local mechanic to do it, haven't decided if I want to spend the money on that just yet.
 
I ordered a new PCM. There’s no way all four sensors are bad at once. I checked for broken connections, fuses, etc. and everything was good.

Worst case, I can send the PCM back since it has a 60 day no questions asked return policy. I have a second car I can drive in the meantime.
 
Originally Posted By: oilpsi2high
I ordered a new PCM. There’s no way all four sensors are bad at once. I checked for broken connections, fuses, etc. and everything was good.

Worst case, I can send the PCM back since it has a 60 day no questions asked return policy. I have a second car I can drive in the meantime.


I have seen this before. Unfortunately the replacement PCM we got from AAP caused a new problem. I think it was something to do with the purge solenoid.
 
Originally Posted By: AVB
Originally Posted By: oilpsi2high
I ordered a new PCM. There’s no way all four sensors are bad at once. I checked for broken connections, fuses, etc. and everything was good.

Worst case, I can send the PCM back since it has a 60 day no questions asked return policy. I have a second car I can drive in the meantime.


I have seen this before. Unfortunately the replacement PCM we got from AAP caused a new problem. I think it was something to do with the purge solenoid.


You may be onto something there.

From a write-up on diagnosing O2 sensor problems (http://www.autoserviceprofessional.com/a...iagnosis?Page=3) comes this quote: "But, if you have a code in the P00 as opposed to the P01 range for the oxygen sensor, suspect that something is confusing the computer."
 
Originally Posted By: oilpsi2high
I ordered a new PCM. There’s no way all four sensors are bad at once. I checked for broken connections, fuses, etc. and everything was good.

Worst case, I can send the PCM back since it has a 60 day no questions asked return policy. I have a second car I can drive in the meantime.


Its doubtful the PCM is at fault. The PCM only triggers the heater ground circuit and monitors the heater operation, it does not carry the high amp electrical load to the heater circuit.
I cant remember ever seeing the heater circuit not fused somewhere and use a relay. Do you have a wiring diagram?
 
Originally Posted By: Trav
Originally Posted By: oilpsi2high
I ordered a new PCM. There’s no way all four sensors are bad at once. I checked for broken connections, fuses, etc. and everything was good.

Worst case, I can send the PCM back since it has a 60 day no questions asked return policy. I have a second car I can drive in the meantime.


Its doubtful the PCM is at fault. The PCM only triggers the heater ground circuit and monitors the heater operation, it does not carry the high amp electrical load to the heater circuit.
I cant remember ever seeing the heater circuit not fused somewhere and use a relay. Do you have a wiring diagram?


Looks like it's powered by the PDC and grounded in the PCM. There's also ground G105 for the downstream, but I'm also having issues with both upstreams and those are grounded in the PCM. G105 is also for clutch interlock, ac pressure, ps pressure and ac compressor clutch which all work normally.

This engine doesn't have a fuse/relay config for the H02.

 
Did you check for power at the PCM? They seem to run in the same harness as the transmission control wiring didn't you have an issue in that area?
Yes i see from the diagram it does not appear to use a relay. I need to look at diagrams here on a bigger screen.
 
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The only issue was the reverse light sensor/switch was bad. I replaced that and the reverse lights work again. No TCM since this is a manual trans.

This is a Jeep/Dodge thing with those P00xx o2 heater codes and bad PCMs. I'm hoping this fixes it. In the meantime I'm going to reset the CEL and drive it and hope I can get it to pass the stupid NY emissions inspection where they hook it up to the computer and it checks the MIL and readiness codes.
 
You right they don't seem to protect the circuit externally anyway for whatever reason. Does it have power at the heater circuit though that all I am wondering?
One is working right? So that one and the one on the same circuit must have power. I hope it works out and you can get a sticker.
 
The fact that there are 3 of the 4 throwing the same DTC is surely significant, but I’m wondering if zeroing in on why that 4th one isn’t also in fault might be the quickest way to identify the root culprit.

I don’t know, just thinking out loud, sorry I don’t have anything of substance that could actually be used for something on this.
smirk.gif
 
Mine has the California emissions.

I used the wiring from the 2001 service manual (couldn't find an 03 version online.)

PCM should be here either Saturday or next week sometime, so we'll see if that fixes it. I'm thinking it will.
 
If this wasn't a Chrysler product.....I would seriously question a PCM replacement. Even then I would go through the motions of quick testing the heater circuits with a test light at the PCM connector pins. The test light should light on all 4 heater control pins.

(Test Light hooked to B+, All PCM Connectors unplugged)
 
It took me a while to convince myself that it was the PCM on the one I was dealing with. I had the heater circuit on all 4 bad. That was the only symptom the truck had, it ran great, but the check engine light stayed one.
 
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