Thanks for the update Matthew. Hope that does the trick for you. You may still get a code for the O2 heater circuit since the work you did really didn’t address that issue.
OK, keep in mind that historically, it has taken about 20 miles for any codes to turn on after disconnecting the battery or clearing the codes with the scanner, and all codes have always come up at the same time. Yesterday the codes were cleared via the battery. This morning after less then a mile, the service engine soon light came on. The scanner was plugged in at the time and recorded live data then, and later when I was on the highway. Right now the scanner is reading 1 “stored code”: P0155 (“O2 Sensor Heater Circuit Bank 2 Sensor 1”) and 1 “Pending Code”: P1131 (“Lack of HO2S11 Switch - Sens Indicates Lean”). I have never had a “pending code” before. THERE IS NO FREEZE FRAME DATA that my scanner recorded.
Remember, if it helps, I can always post the detailed data that the scanner records.
I think the pending code is a good thing. I think this means the code has cleared and the pending will go away after the ECU sees enough engine start/run cycles with no code being set for that particular issue. I’m not sure how many cycles it will take, perhaps a few. So it looks to me you have that problem fixed. The O2 heater circuit is still an issue but we knew that already.
It has been brought up to me before that the remaining problem could have to do with the distributer and that I should do a test involving a timing light. I think I might pick this one up: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=3343 and try it.
EDIT: OK, so it turns out I don’t actually have a distributor. I have a “distributorless ignition system”, more specifically a " Electronic Ignition (EI? High Data Rate) Ignition System". So I’m researching what that is all about. Here is what Chilton says about it:
The Electronic Ignition (EI High Data Rate) system is used on the 3.0L DOHC engines. The system consists of the following components:
- Crankshaft Position (CKP) sensor
- Ignition coil
- Desired spark angle from the Powertrain Control Module (PCM)
- Related wiring
The Crankshaft Position (CKP) sensor is a variable reluctance sensor triggered by a 36 minus 1 tooth trigger wheel located inside the engine front cover. The sine wave signal generated from the CKP sensor is known as the CKP sensor signal. This signal provides two types of information to the Powertrain Control Module (PCM): the position of the crankshaft in 10 degree increments and crankshaft speed (rpm). The PCM will use this information along with the spark advance information to determine when to turn the ignition coil on or off.
The ignition coil contains separate coils. Each coil is controlled by the PCM through two coil leads. Each coil activates two spark plugs simultaneously.
One spark plug is activated on the compression stroke. This spark plug uses the majority of the ignition coil’s stored energy. The other plug is activated simultaneously on the exhaust stroke. This plug will use very little of the coil’s stored energy. These two spark plugs are connected in series so that the firing voltage of one spark plug will be negative with respect to ground and the other spark plug will be positive with respect to ground.
And, it turns out that my county library system does NOT have (free) access to www.ALLDATA.com, but it DOES give me access to Chilton’s repair guide, online, from my own home, in a searchable format (it isn’t just one big PDF)… which is pretty slick.
For what it’s worth, here is what Chilton says about P0155:
Trouble Code: P0155 (3.0L V6 VIN S Auto)
HO2S-21 (Bank 2 Sensor 1) Heater Circuit Malfunction
Number of Trips to Set Code: 2
OBD II Monitor Type: CCM Details
Indicators: MIL Details
Trouble Code Conditions:
Engine running for 5 minutes, and the PCM detected an open or shorted condition, or excessive current draw in the heater circuit.
Possible Causes:
* HO2S heater power circuit is open
* HO2S heater ground circuit is open
* HO2S signal tracking (due to oil or moisture in the connector)
* HO2S is damaged or has failed
* PCM has failedI don’t see how the P0155 code could be related to the ignition area. That information is incorrect as far as I can see.
The possible causes you stated in your last posting are correct. You can make some voltage and resistance checks to see what is going on with the heater circuit. I think the PCM is supposed to ground the heater lead to make it turn on. By checking the voltage on the PCM pin you will be able to see if the heater is getting voltage or not. You should be able to compare bank 1 and 2 readings if you have any questions.
I ran out of day light today, but I will anxiously wait until after work tomorrow to test the wires. Using Chilton I now have a diagram with labels for all of the pins, so I know which is which, but I don’t have the Hxx charts… Though I like your idea that I should be able to simply compare the readings for 1 and 2, that makes sense to me.
I think you have a good handle on how to check out the heater circuit. You will find out what is going on with it. If you need a small diameter probe to check things out with on a connector you can use a pin or small paper clip to touch your meter probe to.
Warning in How To Tune and Modify Ford Fuel Injection book, scroll to page 19: http://books.google.com/books?id=V6KVydlB0J0C&pg=PA16&lpg=PA16&dq=oxygen+sensor,+ford,+5+volt&source=web&ots=STk9N8Hbma&sig=4duhgyAtXeIjTfUAgG5S6CGKCyk&hl=en&sa=X&oi=book_result&resnum=7&ct=result#PPA19,M1
Special Warning: Connecting an ohmeter to an EGO sensor will destroy the EGO sensor.
Yikes. I guess I’ll avoid those then… Thanks for the heads up hellokit!
Thanks for the info there Hellokit. That is interesting. The heater circuit is seperate from the sensor circuit as we know, and it is no trouble to measure that portion of the sensor with an ohmmeter at least.
It’s seperate? I’m confused now about how I can test the O2 sensors. On my PCM wiring diagram it calls all of the O2 sensors “Heated Oxygen Sensor #X”…
Really though, if I look back through the detailed sensor data that the scan tool recorded while I was driving, “O2B1S1(V)” consistently reads “0.000”. So isn’t that a pretty clear indication that it’s either the sensor or the wire? All of the sensors are brand new. I do have 2 that I have yet to return in case it really is bad, but until I understand more fully what I can actually test, I’m going to try following the wire for signs of damage…
BIG EDIT: When I tested just the ECT sensor, it read about 12kohms (the car has not been run for 2 hours). When I tested the wire 38 and 91 they came up as about 12kohms as well. A successful test!
Hey, how about this: To test the wiring of the faulty O2 sensor, what if I disconnect the bundle of wires from the PCM, then disconnect the wiring from the sensor and bridge the two wires together with another piece of wire, under the car. Then check the ohms of that wire by testing it against the “signal return” wire again. I would EXPECT 0 ohms to register if the wire is indeed damaged.
Though, I don’t want to think about what my next test will be if that turns out to be fine…
Yes, you’ve got the idea! You’ll find it an aid to following wiring diagrams, if you printout the diagram and use color pencils to trace each wire of interest.
You can do resistance (ohms) checks on the wiring by disconnecting the component on each end. Check ohms from 91 (gray/red wire) at the PCM connector to the gray/red wire at the disconnected plug from bank 1, front, oxygen sensor. Then, PCM 60, gray/light blue wire to the plug.
Check bank 1, front, O2 heater wire PCM 93 red/white wire to the O2 plug. Then, PCM 71 red wire (the VPWR …12 volt Vehicle Pwr) to the O2 plug. All should be under 1 ohm.
You can do VOLTAGE measurements anywhere. Just don’t pierce the wires…use backprobes.
If the installed O2 sensor has 4 loose wires, out of the box, like this picture: http://www.autozone.com/R,732531/vehicleId,2398304/initialAction,partProductDetail/store,1140/partType,00117/shopping/partProductDetail.htm Someone may have misconnected the wires from a new O2 sensor. Look at the instructions which came with the O2 sensor. Look at the installed O2 sensor wiring. Are they connected to the right wires?
Matthew,
I think you are taking readings on the wrong sensor. According to the latest scanner data the P0155 error code was for bank 2 sensor 1 or 21. A couple of posts ago you state it is bank 1 sensor 1 or 11. You need to be on bank 2.
Hellokit,
I think you are on to something when you mentioned about the possible miswiring of the bank 2 sensor. I’ll bet that is what happened. If the sensor portion got tied to the heater circuit the sensor may now be damaged.
First, this may or may not be important. All I really did last night was check the ECT sensor and it’s wiring. Aside from that I physically searched for the O2 sensors near the catalytic converter and tugged on the wires of one gently to make sure that its plug was connected to the cars wiring. Of course, the wiring was unplugged from the PCM, so all of the stored codes were cleared. With those things in mind, I drove to work today and the engine light did NOT come on. That’s was a little surprising considering that it took less than a mile last time codes were cleared. When I got to work (25 min of driving with some highway speeds) (oh, and it was in the low 70s this morning with light rain), I plugged in the scan tool. NO stored codes. This time there were two pending codes. The P0155 that we all know and love, which was pending yesterday, AND P1131, which has not been pending before, just stored. So could this mean anything special? Maybe I was pulling on the correct sensor wires (I don’t know which sensor is actually bank 1 sensor 2, I haven’t figured that out yet) and in doing so, the damaged wire that was maybe previously resting against some piece of metal is now not touching anything? I didn’t do any testing with the scanner this morning because I didn’t expect anything new, but I will after work to see what the sensor readings are.
Now, I need to concentrate and research to respond fully to you guys last two posts, but for now: Yes, my O2 sensors have 4 loose wires that are not wrapped or anything (should I go ahead and wrap them with electrical tape?), coming from the sensor itself to the plug. Hopefully the sensors have a brand name and model on them somewhere because the mechanic installed them so I don’t have the instructions. Keeping track of these damn O2 sensors is becoming a challenge to me… You are correct Cougar, it is bank 2 sensor 1 that is throwing the P0155. What I did was look at the live data, and searched for the O2 sensor that was reading 0.000, if you do that (see below), you see that O2B1S1 is showing 0.000. So why isn’t that the sensor that is throwing a code?l
If you scroll all the way to the bottom (56 pages…) and look at the last bit of data, which represents about 20 minutes of driving, where I went from city driving to highway driving, you get this:
? DTC_CNT 2
? FUELSYS1 CL_Fault
? FUELSYS2 N/A
? LOAD_PCT(%) 42.0
? ETC(?C) 91
? SHRTFT1(%) -3.9
? LONGFT1(%) -5.5
? SHRTFT2(%) -2.3
? LONGFT2(%) -5.5
? RPM(/min) 2578
? VSS(km/h) 107
? SPARKADV(?) 37
? IAT(?C) 36
? MAF(g/s) 21.67
? TP(%) 20.8
? O2S B1S12–B2S12–
? O2B1S1(V) 0.000
? SHRTFTB1S1(%) 0.0
? O2B1S2(V) 0.600
? O2B2S1(V) 0.205
? SHRTFTB2S1(%) -3.1
? O2B2S2(V) 0.675
? OBD OBD2
? ------------------
? DTC_CNT 2
? FUELSYS1 CL_Fault
? FUELSYS2 N/A
? LOAD_PCT(%) 41.2
? ETC(?C) 91
? SHRTFT1(%) 0.8
? LONGFT1(%) -5.5
? SHRTFT2(%) -3.9
? LONGFT2(%) -5.5
? RPM(/min) 2586
? VSS(km/h) 107
? SPARKADV(?) 37
? IAT(?C) 35
? MAF(g/s) 22.04
? TP(%) 21.2
? O2S B1S12–B2S12–
? O2B1S1(V) 0.000
? SHRTFTB1S1(%) -3.9
? O2B1S2(V) 0.585
? O2B2S1(V) 0.300
? SHRTFTB2S1(%) 0.0
? O2B2S2(V) 0.630
? OBD OBD2
By the way, in case anyone was wondering (I just thought of this) as to why I’m having all of these problems all the sudden, I can tell you exactly why. I recently moved to a state that does emission testing after living in Florida, which does not require any kind of testing, for some five years. The engine light was not on back then, but things probably were starting to deteriate, like the hoses most certainly.
Wire colors on Bosch replacement oxygen sensors, Step 7, on page 29: http://www.bosch.com.au/content/language1/downloads/Section_A.pdf
The way I understood it was the P0155 code was stored and the P1131 was pending. Just the opposite of what you stated. Looking back in the posts seems to confirm this.
To figure out which sensor is which is easy. Bank 1 refers to the exhaust system tied to #1 cylinder. So Bank 1 sensor 1 refers to the sensor before the CAT and Bank 1 sensor 2 is on the same bank after the CAT. The same scheme goes for Bank 2 on cylinder #2.
Edit:
I’m not sure why you aren’t getting a code now. It looks to me your playing with the sensor wires changed things somehow. It looks like the sensor for Bank2 Sensor1 is now working ok and I assume this would be due to a bad connection that is now working ok. Now you need to make sure the sensor wires from Bank 1 Sensor 1 are connected ok since there is now no sensor reading coming from it.
You’re right of course Cougar, about the codes. Note that I have yet to disconnect any wire from any O2 sensor. On my drive home I will hook up the scanner and force it to record live sensor data. Then at home I will put the car up on ramps, check to make sure that the O2 sensors are wired properly according to hellokit’s link (thanks for the link!), check the voltage of B2 S1 (haven’t used that setting on a multimeter before), and check connections and possibly physical damage.