steve56 Posted April 27, 2016 Share Posted April 27, 2016 Have 2000 OBW with CEL P1130 and P1133. Image is live data. How do I read and trouble shoot 02 malfunction. Link to comment Share on other sites More sharing options...
Fairtax4me Posted April 28, 2016 Share Posted April 28, 2016 (edited) That sensor type should show around 3.3v pretty steady. Higher voltage, 3.5-4.0v, shows a lean reading. Lower voltage, 3.1-2.8v, shows a rich reading. Fuel trim isn't too far off, but the system is still in open loop in that shot. Was the engine up to operating temp? 1133 is the code for the heater circuit which could mean the connector has some dirt or corrosion in it, or the sensor could be damaged. Check in the connector first. Also check the wiring from the connector to the sensor. Not sure on the 2000 model but on the older cars the front sensor wiring runs right next to the axle and can rub on the axle if it gets loose. Edited April 28, 2016 by Fairtax4me Link to comment Share on other sites More sharing options...
Cougar Posted April 28, 2016 Share Posted April 28, 2016 Code P1130 indicates an open circuit on the O2 sensor and code P1133 indicates low voltage on the heater circuit. It sounds to me that the two wire pairs going to that sensor may be reversed. If that sensor was just recently installed then I would check that out. If the sensor hasn't been recently replaced then perhaps the connector to it has a problem or the sensor itself is just bad. Link to comment Share on other sites More sharing options...
steve56 Posted April 28, 2016 Author Share Posted April 28, 2016 That sensor type should show around 3.3v pretty steady. Higher voltage, 3.5-4.0v, shows a lean reading. Lower voltage, 3.1-2.8v, shows a rich reading. Fuel trim isn't too far off, but the system is still in open loop in that shot. Was the engine up to operating temp? 1133 is the code for the heater circuit which could mean the connector has some dirt or corrosion in it, or the sensor could be damaged. Check in the connector first. Also check the wiring from the connector to the sensor. Not sure on the 2000 model but on the older cars the front sensor wiring runs right next to the axle and can rub on the axle if it gets loose. Update:FuelSys stays in open loop after 15 min of driving. The ST FTRM1 stays at 0% The LT FTRM1 goes betwween -9.0% and -4.0% 02S11 (v) Stays at 3.79 02S12 (v) goes between .04 and .90 Pulled the connector to the upstream 02 Sensor and the resistance betweed the two black heater wires is unlimited (no resistance) That should be enough info to diagnose whats going on. However it still insn't clear to me what the malfunction is. Link to comment Share on other sites More sharing options...
steve56 Posted April 28, 2016 Author Share Posted April 28, 2016 That sensor type should show around 3.3v pretty steady. Higher voltage, 3.5-4.0v, shows a lean reading. Lower voltage, 3.1-2.8v, shows a rich reading. Fuel trim isn't too far off, but the system is still in open loop in that shot. Was the engine up to operating temp? 1133 is the code for the heater circuit which could mean the connector has some dirt or corrosion in it, or the sensor could be damaged. Check in the connector first. Also check the wiring from the connector to the sensor. Not sure on the 2000 model but on the older cars the front sensor wiring runs right next to the axle and can rub on the axle if it gets loose. Update:FuelSys stays in open loop after 15 min of driving. The ST FTRM1 stays at 0% The LT FTRM1 goes betwween -9.0% and -4.0% 02S11 (v) Stays at 3.79 02S12 (v) goes between .04 and .90 Pulled the connector to the upstream 02 Sensor and the resistance betweed the two black heater wires is unlimited (no resistance) That should be enough info to diagnose whats going on. However it still insn't clear to me what the malfunction is. Link to comment Share on other sites More sharing options...
Fairtax4me Posted April 29, 2016 Share Posted April 29, 2016 The sensor may not be getting hot enough to function properly, or the sensor element inside could have been damaged when the heater element burned out. The heater element is essential on modern A/F ratio sensors because they have to operate at about 1200°F. The heater element remains on until the sensor reaches that temp, then it turns off. Most vehicles will monitor the heater resistance and turn the heater on and off as needed during normal driving so the sensor maintains the correct temp. If the heater stops working the sensor takes much much longer to get to operating temp and will keep the fuel system from going to closed loop due to the sensor not working correctly. Link to comment Share on other sites More sharing options...
Cougar Posted April 29, 2016 Share Posted April 29, 2016 From what you say about the resistance of the two black leads it appears the resistance is infinite (an open connection), that is the opposite of having no resistance. A piece of copper wire has basically no resistance to it (very, very small). If the two black leads really are for the heater then it is bad and you need to replace it. If the sensor is designed so that one of the black wires is used for the signal pair and the other black wire goes to the heater circuit then the wiring to the sensor is incorrectly connected. Link to comment Share on other sites More sharing options...
steve56 Posted April 29, 2016 Author Share Posted April 29, 2016 The sensor may not be getting hot enough to function properly, or the sensor element inside could have been damaged when the heater element burned out. The heater element is essential on modern A/F ratio sensors because they have to operate at about 1200°F. The heater element remains on until the sensor reaches that temp, then it turns off. Most vehicles will monitor the heater resistance and turn the heater on and off as needed during normal driving so the sensor maintains the correct temp. If the heater stops working the sensor takes much much longer to get to operating temp and will keep the fuel system from going to closed loop due to the sensor not working correctly. I thought the 02 voltage was supposed to vary between .01volts and .9 volts My 02 upstream stays at 3.70(v) and the downstream varies between,04(v) and .9(v).I dont see either Higher voltage, 3.5-4.0v, shows a lean reading. Lower voltage, 3.1-2.8v, shows a rich reading. I'm confused. Link to comment Share on other sites More sharing options...
steve56 Posted April 29, 2016 Author Share Posted April 29, 2016 From what you say about the resistance of the two black leads it appears the resistance is infinite (an open connection), that is the opposite of having no resistance. A piece of copper wire has basically no resistance to it (very, very small). If the two black leads really are for the heater then it is bad and you need to replace it. If the sensor is designed so that one of the black wires is used for the signal pair and the other black wire goes to the heater circuit then the wiring to the sensor is incorrectly connected. Yes I havn't absolutly varified that the two black wires are for the 02 heater. Its a 4 wire 02sensor so my statement on the two black wires being for the heater wires is just an assumption. My FSM doesn't seem to have a wiring diagram for the 02 sensor. Link to comment Share on other sites More sharing options...
Fairtax4me Posted April 29, 2016 Share Posted April 29, 2016 4 wire sensor will have three wire colors. One color for signal, One color for signal ground One color for heater wires power and ground will be the same color. Upstream sensor on that car is a wideband A/F ratio sensor and works at around 3.3v. Link to comment Share on other sites More sharing options...
Cougar Posted April 30, 2016 Share Posted April 30, 2016 If I understand correctly it seems that Fairtax4me is stating that the heater wires are one color (2 black wires) which showed open using the ohmmeter. If that is correct the sensor is bad. Link to comment Share on other sites More sharing options...
steve56 Posted April 30, 2016 Author Share Posted April 30, 2016 (edited) 4 wire sensor will have three wire colors. One color for signal, One color for signal ground One color for heater wires power and ground will be the same color. Upstream sensor on that car is a wideband A/F ratio sensor and works at around 3.3v. Thanks for clearing that up. How do I trouble shoot the O2 sensor? My current Actron live data info is: ST FTRM1 (%) 0.0 LT FTRM1 (%) 0.0 FUEL SYS 1 Open O2S12 (v) 0.915 ST FTRM12 (%) 0.0gr O2S11 (v) 3.797 20 min driving. Engine at operating temp. CEL P1133 Heater input high. Also it has a manual trans. The auto and manual trans have different upstream O2 sensors. Edited April 30, 2016 by steve56 Link to comment Share on other sites More sharing options...
steve56 Posted April 30, 2016 Author Share Posted April 30, 2016 If I understand correctly it seems that Fairtax4me is stating that the heater wires are one color (2 black wires) which showed open using the ohmmeter. If that is correct the sensor is bad. Yes Cougar I saw that also. The two O2 sensor wires that are the same color are black. When I disconnected the the O2 sensor from wiring harness and did a resistance check between the two black wires I found no resistance. As you stated earlier, that implies an open circuit on the heater. I'm tring to decide if that is a conclusive enough test for a bad O2 sensor. I could just buy a new O2 sensor and check the resistance on the same color wires. However they are $140 with tax. I'm trying to avoid just parts swapping as part of my diagnosis at this point. Link to comment Share on other sites More sharing options...
Fairtax4me Posted April 30, 2016 Share Posted April 30, 2016 Is it showing 0.0 ohms or is it showing O.L? O.L is Over Limit and indicates the circuit is open, or not connected electrically. This could be because the heater element is burned out. O.L could also be due an incorrect range selection on your meter. 0.0 ohms is low/no resistance and shows that the wiring for the element may be shorted together inside the sensor. Either way the sensor is dead. Link to comment Share on other sites More sharing options...
Cougar Posted April 30, 2016 Share Posted April 30, 2016 You saw the opposite of no resistance, you saw infinite resistance. A short circuit has no resistance (zero ohms) and a open circuit has infinite resistance. If the sensor worked in the past an the wiring to the sensor hasn't changed since that time, and you have 12 volts on the black wires with the ignition ON, then the sensor is bad. Link to comment Share on other sites More sharing options...
steve56 Posted April 30, 2016 Author Share Posted April 30, 2016 Is it showing 0.0 ohms or is it showing O.L? O.L is Over Limit and indicates the circuit is open, or not connected electrically. This could be because the heater element is burned out. O.L could also be due an incorrect range selection on your meter. 0.0 ohms is low/no resistance and shows that the wiring for the element may be shorted together inside the sensor. Either way the sensor is dead. Yes its O.L. not 0.0 omms My Fluke 115 meter has auto range, so I think Im getting thee correct reading Link to comment Share on other sites More sharing options...
steve56 Posted April 30, 2016 Author Share Posted April 30, 2016 You saw the opposite of no resistance, you saw infinite resistance. A short circuit has no resistance (zero ohms) and a open circuit has infinite resistance. If the sensor worked in the past an the wiring to the sensor hasn't changed since that time, and you have 12 volts on the black wires with the ignition ON, then the sensor is bad. My only test was an ohms test with the O2 sensor unplugged from the harness. To do a 12v test with ignition On, are you talking about plugging the O2 sensor back into the harness and backprobing the black wires? Im not sure how to safely do that without potentially shorting the ecm. What is the safe way to do this to find the 12v? Link to comment Share on other sites More sharing options...
heartless Posted April 30, 2016 Share Posted April 30, 2016 Is it showing 0.0 ohms or is it showing O.L? O.L is Over Limit and indicates the circuit is open, or not connected electrically. This could be because the heater element is burned out. O.L could also be due an incorrect range selection on your meter. 0.0 ohms is low/no resistance and shows that the wiring for the element may be shorted together inside the sensor. Either way the sensor is dead. your answer is right there ^^ Link to comment Share on other sites More sharing options...
Cougar Posted May 1, 2016 Share Posted May 1, 2016 I concur doctor. Link to comment Share on other sites More sharing options...
steve56 Posted May 1, 2016 Author Share Posted May 1, 2016 (edited) Wow AF sensors sure are expensive for a metal tube and a couple of circuits With this AF sensor having a bad heater element, will it alway stay in open loop, or when the engine heats up enough should it go into closed loop. Since I cant get mine to go into closed loop,I'm thinking the ecm must see the bad heater and just keep it in open loop. Edited May 1, 2016 by steve56 Link to comment Share on other sites More sharing options...
Cougar Posted May 3, 2016 Share Posted May 3, 2016 The other code seemed to indicate that the sensor signal has a problem also, not just the code for the heater. Link to comment Share on other sites More sharing options...
steve56 Posted May 3, 2016 Author Share Posted May 3, 2016 (edited) The other code seemed to indicate that the sensor signal has a problem also, not just the code for the heater.Yes the P1133 is for heater input high. With my Actron scan tool live data I'm getting an O2S11(V) that is stuck at 3.797V) and an OS12(V) that varies between .08(V) and .9(V). I cleared the codes and the P1130 for air fuel cicuit open erased.The P1133 stays. The scan tool shows 0.0 or all fuel trims. Still staying in open loop. The 02S11(V) stuck at 3.797 volts seem to be the key to the problem. I know that reading is just interpretive voltage and the ecm is really looking at micro amp changes. However thats the one reading that is unchanging. I have the FSM flow chart for the P1131 DTC. It instructs to test between ECM and Chasis ground. Depending on whether its more than 8(V) or less than 8(V) it says its either a bad ECM or short cicuit in harness between A/F sensor connector and ECM. That short circuit test has you look at an apm reading that my Actron scan tool doesn't display. The whole thing seems so confusing to me that replacing the A/F sensor seems to be a better first move. One reason for that is when I do a ohm test between the two black A/F heater wires with the connector unpugged from the harness Im getting OL reading on my multimeter. However I'm geeting a heater circuit good reading another test on my Actron meter. Alot of conflicting data. s Edited May 3, 2016 by steve56 Link to comment Share on other sites More sharing options...
Cougar Posted May 3, 2016 Share Posted May 3, 2016 If you have another sensor to make a comparison test using your meter that would help prove things out. I don't know what the resistance of the heater should normally be but I assume it is less than 100 ohms. I also assume that you meter is an auto-ranging type and you are using a scale that extends to the Meg ohms. Link to comment Share on other sites More sharing options...
steve56 Posted May 3, 2016 Author Share Posted May 3, 2016 If you have another sensor to make a comparison test using your meter that would help prove things out. I don't know what the resistance of the heater should normally be but I assume it is less than 100 ohms. I also assume that you meter is an auto-ranging type and you are using a scale that extends to the Meg ohms. Yes They have the correct A/F sensor at local auto parts store. Thats a four wire for my MT car. The AT cars use a five wire.They were nice enough to take it out of the box and let me test it with my Fluke 115 True RMS multimeter. The new one has 1 ohm resistance between the two black heater wires. Mine tests OL between the two black heater wires.To further muddy the waters, my Actron "Quick Test Resuls" screen shows Oxygen Sens Mon inc. and Oxygen HTR ok. I was looking back at a previous post on here Titled "P1133 DTC Tough to Solve". I know your were helping him also. The bottom line with his issue was, he did all the ECM ground and harness tests. Bought a new ECM and A/Fsensor and still had the P1133. As I remember, he finally just jiggled the right part of wiring harness and his P1133 went away. Link to comment Share on other sites More sharing options...
Cougar Posted May 4, 2016 Share Posted May 4, 2016 Well you have proven the heater is bad on your sensor. That is about the end of the story for that sensor at least. The Fluke knows. Link to comment Share on other sites More sharing options...
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