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Discussion Starter · #1 ·
I am pulling a P0430 catylist effeciency below threshold bank 2. I dont get the bank 1 (P0420). I have a prochamber pipe and a JMS chip that they say has the MIL's turned off. When using my scan tool on realtime monitoring the O2's, bank 2 sensor 2 switches like the fronts (or pretty close). But bank 1 sensor 2 reads 000V all the time and doesn't switch, it does not get the effeciency below threshold fault. They told me I may have a bad O2 in bank 1 sensor 2 causing the fault and it should switch even with the MIL's turned off. I pulled the connector apart in the engine compartmant and swapped the 2 rear O2 wire's that send the signal back to the PCM. I still get 0V on bank 1 sensor 2. I then pulled both signal wires (from l&r rear O2's) pins out of the connector and ran the engine while monitoring them with my DVM. They both switch the same. Then I Ohmed the input back into the PCM to GND and they read the same for the 2 rear O2 return signal inputs. So so far the O2's are good, the wiring checks out. I will have to pull the JMS chip and run it with the GT PCM and see if I get a input for my bank 1 sensor 2 O2.
My thought was maybe my chip only had the MIL turned off for bank 1 sensor 2, and thats why it reads 0V and never gets a fault. But JMS tells me it should switch even with the MIL off for the rear O2's. I know this is a little deep (and long) but I was hoping someone with some knowledge of all this and how the PCM works with the rear O2's off could give me some advice. I'm a electronic tech so this kind of troubleshooting is something I can understand.
JMS has been helpful so far but we are communicating over email right now since I'm on the west coast, so it takes a few days to get an answer. Thanks for any input.
Scott
 

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Discussion Starter · #2 · (Edited)
No input?? Well I pulled the JMS chip out, what a PITA. Car seems to run pretty good without it. I now have both inputs for my rear O2's switching when monitoring with my scan tool (Diablo Hellion). So it must be JMS only turned off one of my rear O2's (bank 1 sensor 2 for my offraod pipe). Will JMS take care of this? Anyone use their chips? I dont think they should charge me:confused: . I guess I'll have to call them. The car doesn't seem to buck as mutch now, still bucks a little at around 2000 rpm. Could it be because the MAF screen is gone? Oil contaminated MAF fron the K&N?
Scott
 
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