Fireman31 Posted December 15, 2008 Report Share Posted December 15, 2008 (edited) Well as the title says, my truck is throwing multiple codes, but the circumstances surrounding it are weird. First off, here are the codes she's throwing..... P0420 - drivers rear 02 sensor, poor cat performance P0430 - passenger rear 02 sensor, poor cat performance P01810 - transmission fluid pressure (TFP) manual valve position switch invalid state The truck first started throwing the 1810 code after the tranny swap every 6 or 7 ignition cycles, wiggling the main transmission harness/plug cured that.....she was trouble free for the last month and a half. Last week, I had the 2 slip joints in the mid-pipes of my Dynatech kit welded(I got tired of re-tightening the band clamps). The shop found that my passenger rear 02 had fraid wiring from the but of it rattling against the chassis. I was advised that I may need to replace it if it starts to throw codes. Around a day or so later on a rainy day, the truck finally threw a PO430. I figured that the rain was causing some arcing issues or something from the exposed wiring. After the rain stopped and the truck dried out, she started throwing all 3 codes on friday evening in stead of just the one. I picked up a new 02 sensor on saturday and replaced it yesterday hoping it would cure issue. Well low and behold just as I was getting to work today, the CEL came back on and all three codes returned. The circumstances are weird though, the truck has to be running for at least 1/2 hour in order for the codes to pop up. I did alot of local running around on saturday, didn't let the truck run for maybe more then 20 minutes at a time, no CEL came on. I dont know if this issue is related to something being welded under the truck, maybe they nicked a harness, who knows? All I know is that the truck was fine for almost two days until it started to rain. BTW, my cats are fine since the shop inspected them while everything was down. What do you guys think? Edited December 15, 2008 by Fireman31 (see edit history) Quote Link to comment Share on other sites More sharing options...
Hankg42 Posted December 15, 2008 Report Share Posted December 15, 2008 Damn it, Dan. I'm sorry to hear that you're having problems again. Certainly no expert here, but I can't logically see that the O2 sensor codes and the trans code can be related. I would think they would have to be separate issues. What about the second O2 sensor, the one you didn't replace? Did that one check out OK? Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted December 15, 2008 Author Report Share Posted December 15, 2008 Damn it, Dan. I'm sorry to hear that you're having problems again. Certainly no expert here, but I can't logically see that the O2 sensor codes and the trans code can be related. I would think they would have to be separate issues. What about the second O2 sensor, the one you didn't replace? Did that one check out OK? The other 02 sensor is okay, but the one I replaced threw the same code again this morning. Something is telling me this is an electrical issue under my truck, I guess I should crawl under tonight and have a look........ Quote Link to comment Share on other sites More sharing options...
wody Posted December 15, 2008 Report Share Posted December 15, 2008 (edited) i've been getting the P0420 codes lately as well. for some reason, i think it may have something to do with cooler weather. while maintaining higher speeds there isn't a problem since the egt's are higher as well, but when idling is when my code is thrown. just a thought though. i picked this theory up after reading other similar threads. that or gas is cheap right now for another reason (H2O) . i just cleared the code and went about my bis. Edited December 15, 2008 by WODY™ (see edit history) Quote Link to comment Share on other sites More sharing options...
blackbeast ss Posted December 16, 2008 Report Share Posted December 16, 2008 damm sorry your having problems dann,you can allways gutt your cats and delete the rear 02s Quote Link to comment Share on other sites More sharing options...
Hankg42 Posted December 16, 2008 Report Share Posted December 16, 2008 Did you have a chance to look at it last night Dan? Quote Link to comment Share on other sites More sharing options...
detjoe Posted December 16, 2008 Report Share Posted December 16, 2008 I need to dig up the OBDII flow chart. There is a certain way to run the truck for the computer to test all of the sensors, I would guess the rear o2's take a while to get hot?? here: General Motors Driving CycleA complete driving cycle should perform diagnostics on all systems. A complete driving cycle can be done in under fifteen minutes. To perform an OBDII Driving cycle do the following: 1. Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run. 2. Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim. 3. Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed. 4. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed. 5. Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed. 6. Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3. 7. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst. 8. Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears. Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted December 16, 2008 Author Report Share Posted December 16, 2008 Did you have a chance to look at it last night Dan? No I never did, I got tied up in a few things at the FD after work. Hopefully I will tonight. The funny thing is, I cleared the codes when I left work yesterday and they never came back after a 40 minute drive home. This morning after the truck had been running/driving for around 30 minutes, the two rear 02 codes popped up again, but the trans code did not this time. I am totally stumped here...... Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted December 17, 2008 Author Report Share Posted December 17, 2008 CEL popped back on tonight as I was pulling into my driveway, only threw a PO430 this time Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted December 17, 2008 Author Report Share Posted December 17, 2008 ....and it threw another P0430 two blocks from my office again this morning Quote Link to comment Share on other sites More sharing options...
Krambo Posted December 17, 2008 Report Share Posted December 17, 2008 I feel it has to do with the rear sensors not getting hot enough / voltage problems. Your front O2's are switching fine, LTFT and STFT's are fine (no intake/exhaust leaks pre-front O2's), your cats are visually intact, a new rear sensor did nothing. The rear O2 sensors are heated, correct, are they getting the correct supplied voltage along the heater wire? I believe the only way to throw these codes is to have a delta greater then a "certain voltage" from the primary to the secondary O2's. If the cats are intact, the primary O2's are fine in all aspects and there are no exhaust leaks...it really narrows it down to voltage fluctuations to/from the rears IMHO. Check and recheck for cuts in the wires, water in the connectors and melting / abrasion of the wires (not only on the sensor but also on the truck wiring...there has been alot going on under there in the past 3 months). Time for some scanning software Dan! Even though your LTFT's and STFT's are where they should be,...have you been overusing products such as HEAT or STP fuel treatments for the winter by any chance? I feel your Tranny code is totally independent of the rear O2 codes. You can make a quick resolution to this and delete the 10 or so codes related to the rear O2 sensors in your tune as they have NO impact on the performance of your truck. Then you can get friendly with a long screwdriver and "service" your cats for a little more "performance". Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted December 18, 2008 Author Report Share Posted December 18, 2008 I feel it has to do with the rear sensors not getting hot enough / voltage problems. Your front O2's are switching fine, LTFT and STFT's are fine (no intake/exhaust leaks pre-front O2's), your cats are visually intact, a new rear sensor did nothing. The rear O2 sensors are heated, correct, are they getting the correct supplied voltage along the heater wire? I believe the only way to throw these codes is to have a delta greater then a "certain voltage" from the primary to the secondary O2's. If the cats are intact, the primary O2's are fine in all aspects and there are no exhaust leaks...it really narrows it down to voltage fluctuations to/from the rears IMHO. Check and recheck for cuts in the wires, water in the connectors and melting / abrasion of the wires (not only on the sensor but also on the truck wiring...there has been alot going on under there in the past 3 months). Time for some scanning software Dan! Even though your LTFT's and STFT's are where they should be,...have you been overusing products such as HEAT or STP fuel treatments for the winter by any chance? I feel your Tranny code is totally independent of the rear O2 codes. You can make a quick resolution to this and delete the 10 or so codes related to the rear O2 sensors in your tune as they have NO impact on the performance of your truck. Then you can get friendly with a long screwdriver and "service" your cats for a little more "performance". I hear you on the tuning software, that will be coming once I get a nice boob shaft and supporting hardware in the future. My truck has never seen any fuel additives in the 2-1/2 years I have owned it.....the way I drive it there is really no need for them LOL. Eventually the rear 02 codes will get deleted once the cats take a poop and I punch them out. I want to check everything possible to cause these issues before resorting to that. On a side note, like clockwork, a few blocks from home last night, and a few blocks from work today, the damn CEL came back on........keeps throwing P0430 now, no other codes. We have a break in the recent inclement weather here today, I plan on sliding under the truck tonight for a look...... Quote Link to comment Share on other sites More sharing options...
gixxerrider Posted December 18, 2008 Report Share Posted December 18, 2008 I get the cat codes with the stock PCM in the cold. I believe Zippy turned them off. Your trans code could be from your built trans if you did not retune it. just my 2 cent Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted December 20, 2008 Author Report Share Posted December 20, 2008 (edited) I get the cat codes with the stock PCM in the cold. I believe Zippy turned them off. Your trans code could be from your built trans if you did not retune it. just my 2 cent PCM is set up for the built trans and larger stall, this didnt start until all the welding was done. It has to be electrical, yesterday she threw a 420 and a 430 on the way to work. On my near 2-1/2 hour drive home, she first threw both the 420 and 430 again, then she started throwing just the 420 every 1/2 hour like clockwork. Something must be loose/pinched/burnt/fraid/cut under there, there is no other explanation for this, i am totally boggled.......and the weather here has been so bad the last week I haven't really been able to get under her and have a good look. Edited December 20, 2008 by Fireman31 (see edit history) Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted February 12, 2009 Author Report Share Posted February 12, 2009 (edited) *UPDATE* The truck is still throwing the CEL randomly, but I do have a bit more of a conclusion of what the issue is. I have checked the wiring under the truck and everything is okay. The P0420 and P0430 come on individually, sometimes one or the other, or occasionally both. The truck only throws the light when there is extended idle time, and heavy or stop and go traffic. Highway or spirited driving will not cause the light to come on...and again, it is tempermental time wise. Sometimes it takes 40 minutes to come on, sometimes 10. I have concluded that it is a cat flow issue, and I don't feel that it is related to ambient temperature. It was 60* here yesterday and it threw the light on twice on my way home from work. Other then the damn light popping on and annoying me, the truck is seemingly fine, with absolutely no evidence of a bat cat. My solution to this.....I am going to have the P0420 and P0430 codes deleted from my tune. Once the cats do go bad in the future, they will have a meeting with a big screwdriver. Edited February 12, 2009 by Fireman31 (see edit history) Quote Link to comment Share on other sites More sharing options...
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