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| P0135 and P0136 parts guy says ignore it?; Throwing code P0135 and P0136 should I ignore or replace? | |
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| Tweet Topic Started: Apr 27 2012, 10:59 AM (3,737 Views) | |
| Yazman | Apr 27 2012, 10:59 AM Post #1 |
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Hello all! I have a CEL that is throwing P0135 and P0136. According to the OBD2 scanner this is o2 sensor before and after cat. Two parts stores told me it will not effect performance or gas mileage, but I'm not sure I trust that. I thought that the o2 before the cat determined fuel mix and the o2 after the cat just made sure the cat was working. Will this effect gas mileage? I'm currently getting around 37 combined in a 99 3/5. Thanks! |
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| Bad Bent | Apr 27 2012, 01:21 PM Post #2 |
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Facetious Educated Donkey
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Naw... ignore the parts guy. From my bookmark: http://www.obd-codes.com/trouble_codes/ P0125: Oxygen O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1) What does that mean? This code refers to the front oxygen sensor on Bank 1. The heated circuit in the oxygen sensor decreases time needed to enter closed loop. As the O2 heater reaches operating temperature, the oxygen sensor responds by switching according to oxygen content of the exhaust surrounding it. The ECM tracks how long it takes for the oxygen sensor to begin switching. It the ECM determines (based on coolant temp) that too much time elapsed before the oxygen sensor began operating properly, it will set P0135. Symptoms You will likely notice poor fuel economy the illumination of the MIL. Causes A code P0135 may mean that one or more of the following has happened: 1. O2 Heater element resistance is high 2. Internal short or open in the heater element 3. O2 heater circuit wiring high resistance 4. open or short to ground in the wiring harness Possible Solutions 1. Repair short or open or high resistance in wiring harness or harness connectors 2. Replace oxygen sensor (cannot repair open or short that occurs internally to sensor) My 1996 FSM says to check the connection at the PCM (C2-9) Sensor Ground. The LT GRN/BLK wire (WHT at the sensor) also connects to the TP sensor, MAP sesnor, ECT sensor, IAT sensor and the rear O2 sensor. There is also a fuse in the junction box connected with a BLK/WHT wire. You might use http://sites.google.com/site/suzukiswiftinfo/ if you don't have a FSM. In short, I think you have a ground problem. Check and clean your grounds and connections. I like to use a Dremel tool and small wire brush to clean connections. You can check the sensor the mwebb way with post #19: http://geometroforum.com/topic/4050888/1/?x=40 |
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| dayle1960 | Apr 27 2012, 03:06 PM Post #3 |
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Fastest Hampster EVER
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Great writeup, BB. Glad to have members with your brainpower on GMF. |
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| Bad Bent | Apr 27 2012, 05:30 PM Post #4 |
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Facetious Educated Donkey
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Thanks. I just hope it works.
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| Yazman | Apr 27 2012, 07:28 PM Post #5 |
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Wow you guys are awesome! I will investigate next week after trip. Thanks!
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| Yazman | Apr 28 2012, 01:29 PM Post #6 |
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I cleared the codes and this morning I had no CEL my whole 15 mile trip to work. Later I drove about 2 miles and it came on. Does this mean it's actually the sensor? If so where can I find cheapest universal, I am dirt poor! |
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| Bad Bent | Apr 28 2012, 03:00 PM Post #7 |
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Facetious Educated Donkey
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Clearing the codes is nothing. You need to check the wiring for cracks - in fact check the O2 sensors for cracks. I had a broken sensor on my '91 that LOOKED normal but the insulator was cracked. Seriously, trace the wires, check connections. Anything connected metal to metal unscrew/bolt and clean with sandpaper or steel wool. Usually involves using a ratchet and 10mm socket.![]() You are looking for "open or short to ground in the wiring harness" I believe the computer for your cars is behind the glove box. See if you can see a connection C2-9 and see if it is clean and connected. If you want to check the sensors then use this link: http://geometroforum.com/topic/4050888/1/?x=40 and read post #19. You will need a multimeter (DVOM). To check sensors with a meter use this link: Connections with a T pin. |
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| Yazman | May 5 2012, 07:44 PM Post #8 |
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So I checked all the fuses today and they are good. I took off the 3 connectors to the ECM and they all looked clean. I also followed the wiring from the o2 sensors to the connector and they are intact. I also took apart the o2 connector and sprayed it out with wd40. I'm not sure which ground to clean, so I didn't do that. I'm thinking maybe since I have 101,000 miles it's just the sensors. Let me know what you guys think. Thanks! |
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| Bad Bent | May 5 2012, 10:35 PM Post #9 |
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Facetious Educated Donkey
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Did you check the sensors with a Multimeter? You are probably correct and I'd replace the front sensor with an O'Reilly Auto Parts off-the-shelf item (less likely to be damaged in shipping). They can be damaged easily if dropped. Only suggestion I would have is to use an "electrical connection" cleaner rather than WD-40. It dries without leaving a residue. A few years ago I got a 100 piece Dremel tool kit and I love it. I use the Dremel tool and it's small round wire brush to clean electrical connections in seconds. harbor Freight has 3 kits and one on sale for $11. www.harborfreight.com/catalogsearch/rotary+tool BTW, I cleared the codes maybe 3 times before I gave up on a code and replaced the catalytic converter.
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| Yazman | May 6 2012, 07:37 AM Post #10 |
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Thanks for all the help! One more question, is there any difference between the upstream and downstream sensor besides wire length? Reason I am asking is because the downstream is like $12 cheaper and I would like to use it for the upstream. |
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| Scoobs | May 6 2012, 07:53 AM Post #11 |
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:D
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Dont try and cheap your way out on them, just do it right the first time. |
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| Yazman | May 6 2012, 11:41 AM Post #12 |
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Well, I see where your coming from, but without boring you with my sob story I don't have the money to spend. It looks like I'm gonna go with a universal upstream or downstream installed upstream. For the rear I'm gonna either ignore it since it doesn't effect FE, or get junk yard one to clear CEL. |
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| Yazman | May 6 2012, 05:15 PM Post #13 |
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Actually I just ordered an OE Bosch from amazon for $50. Any idea how to get rid of CEL for downstream o2 without replacing it? |
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I will investigate next week after trip. Thanks!


7:46 PM Jul 10