ASD and oxygen sensors - JeepForum.com
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post #1 of 18 Old 06-22-2016, 10:34 PM Thread Starter
SpecialK2000
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ASD and oxygen sensors

Is it possible for a faulty ASD to prevent power from getting to the O2 sensor heaters and not cause any other issues? I'm getting the P0135 code and I've tried just about everything except replacing the computer and taking the jeep in to my mechanic. I've replaced both upstream sensors with NTK sensors. Rebuilt alternator, purchased brand new battery, checked wiring, tested using a multimeter and determined that the O2 heaters are not getting power. I have not replaced the downstream sensors. I replaced the O2 sensor relays, and checked all of the fuses. Any suggestions would be much appreciated.

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post #2 of 18 Old 06-23-2016, 10:20 AM
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This should have all the wiring diagrams you need to track down the problem: http://api.viglink.com/api/click?for...ice-Manual.zip

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post #3 of 18 Old 06-23-2016, 06:22 PM Thread Starter
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Unfortunately I could not open the link. I do however have the jeep service manual. The big one. I have all the wiring diagrams and I've tried to trace them around but those diagrams are not very easy for the lay person to follow. I am a chemist so I'm capable but those diagrams are tough on the eyes. More difficult than chemistry if you ask me. I'm going to try a new ASD, they're cheap and simple to change. I've tried everything else except changing the downstream sensors and tracing each wire inch by inch. Oh and changing the computer. Thanks for the reply.
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post #4 of 18 Old 06-24-2016, 03:40 AM
Jonny Jeep
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The power from the ASD relay goes to two fuses in the Power Distribution Center. Fuse 21 is for the O2 heaters, everything else runs through fuse 18.
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post #5 of 18 Old 12-01-2019, 03:33 PM Thread Starter
SpecialK2000
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Still getting code P00135. I've tried everything and then some. Checked fuses, traced wires from the O2 sensors to the battery to the computer and back to O2 sensor, replaced O2 sensors with multiple brands, bought new battery, had alternator rebuilt, cleaned all grounds under hood, replaced computer. The wires are in great shape, I tested each O2 sensor and I'm getting power to the O2 sensors and they are grounded. What else could it be? The last thing I can think of is that my starter is covered in oil and dirt. I know, sounds obvious but jeez am I going to rebuild this entire jeep from scratch? Don't get me wrong, I love it, the thing runs beautifully, just can't pass inspection. Thanks for any advice.
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post #6 of 18 Old 12-01-2019, 05:21 PM
CJ7-Tim
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Your gas MPG's should tell you if the O2 are functioning correctly. I would guess that you still have wire harness or wire plug issues.
 
 
P0135 JEEP Possible Causes
  • Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit fuse
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit open shorted to ground
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit poor electrical connection
  • Faulty Engine Control Module (ECM)
    •  
First diagnose P0135 JEEP code
Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded wire plug terminals.
 
P0135 JEEP Tech Notes
The code means that there is a problem with the heater element circuit of the heated oxygen sensor. The control module monitors how long it take the sensor to warm up and start sending an adequate signal. The code is triggered when the sensor is taking too long to warm up. Water getting inside the heated oxygen sensor connector can caused the heated oxygen sensor fuse to blow. Before replacing the sensor, check for the condition of the heated oxygen sensor fuse and connectors. If the sensor and connector are OK, replacing the O2 Sensor 1 usually takes care of the problem
 
Cost of diagnosing the P0135 JEEP code
Labor: 1.0
The cost of diagnosing the P0135 JEEP code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
 
When is the P0135 JEEP code detected?
Current amperage in the front heated oxygen sensor heater circuit is out of the normal range. (An improper voltage drop signal is sent to ECM through the front heated oxygen sensor.
 
P0135 JEEP Possible Symptoms
Engine Light ON (or Service Engine Soon Warning Light)
Possible higher than usual fuel Consumption
 
P0135 Jeep Description
Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. The faster the heated oxygen sensor reaches that temperature the faster the sensor will start sending an accurate signal to the Engine Control Module (ECM).
In order to achieve the require temperature, a heater element is included inside the heated oxygen sensor. The ECM controls the heated oxygen sensor heater element based on signals from the engine coolant temperature and engine load. The ECM controls the heater element circuit by allowing current flow to ground.The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications.
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post #7 of 18 Old 12-03-2019, 08:02 AM
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Still working this, yes it is rocket science as you difficulty following the logic shows- OK my sales pitch.

I am guessing so I want to clear unmentioned things up, this is Calif emissions you have the 2 mini cats, and 4 o2 sensors there. The only code is p0135 and you have a scanner?

You said (confirm) that the sensor heaters do NOT have power (voltage) post #1?

If above statement is correct then trouble shoot at relay, is PCM commanding relay, voltage at C13 and PCM is (grounding) relay C15 to begin checking.

I have something in my thoughts IDK a TSB or details about this code - I will check notes.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #8 of 18 Old 12-03-2019, 08:08 AM
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this might help
Attached Files
File Type: pdf 00XJ PDC.pdf (42.5 KB, 7 views)

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #9 of 18 Old 12-23-2019, 07:59 AM Thread Starter
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I am getting P0135 and P0155 at the same time. I should have mentioned that earlier in this thread, problem is I mentioned it in another thread. I have no trouble following the logic. One problem is the troubleshooting website that I was using had me testing the power to the O2 sensors with the Key On Engine Off. No power was getting to the sensors. I guess in hindsight I should have known that was wrong but its a pretty good website and I think the link was sent to me through this forum. And I thought with the key on power would be going to the O2 sensors. Anyway I've followed the power wire from the battery through the PDC to the fuse, the relay, the ASD, the wire connector to the splice and to each of the upper oxygen sensors. (I've taken it to my best mechanic and he couldn't fix it.). The wires are in perfect condition. I checked the volts going to each of the above points. With the engine running I get 14 volts all the way to the wire coming out of the wire harness connector. I actually peeled back some of the wire just so I could confirm that there was power running through the wire. There is power in the DG 20 gage wire that leads to the two upstream O2 sensors. But the power is not getting to either of the upstream O2 sensor connectors. But I check the continuity of the wires and the resistance is 0.00. This makes absolutely no sense to me. I checked the splice where the power splits to both upstream sensors and it looks great. I even bought a new computer from carcomputerexchange.com. I spoke with a technician there about the TSB and the new software and he said your new computer has the correct software for your vehicle. Now, based on the wire test that I ran the computer wouldn't be involved at the point so I am just stumped. My next plan is to bring the jeep to this local guy who is a whiz. I haven't brought it to him yet because I didn't want to give up on this one.
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post #10 of 18 Old 12-23-2019, 11:29 AM
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Yes you are correct about the check with key ON, the ASD relay sometimes will shut down in @3seconds if engine not running. FYI it is sometimes 'tied' wired with the fuel pump relay.

Will need to double check 2000xj manual for details - wiring diagrams etc.

Will add info when I get time to check manual and TSB's.

P0135 is B1S1, p0155 is B2S1 both are suspected heater circuit issues.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #11 of 18 Old 12-23-2019, 12:47 PM
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Quote:
Originally Posted by SpecialK2000 View Post
Is it possible for a faulty ASD to prevent power from getting to the O2 sensor heaters and not cause any other issues? I'm getting the P0135 code and I've tried just about everything except replacing the computer and taking the jeep in to my mechanic. I've replaced both upstream sensors with NTK sensors. Rebuilt alternator, purchased brand new battery, checked wiring, tested using a multimeter and determined that the O2 heaters are not getting power. I have not replaced the downstream sensors. I replaced the O2 sensor relays, and checked all of the fuses. Any suggestions would be much appreciated.
It looks like you start replacing parts one by one w/o diagnosing first.

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post #12 of 18 Old 12-23-2019, 01:45 PM
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Ok the ASD relay does not provide power to the B1S1 and B2S1 o2 heater circuits.
The o2 sensor heaters utilize a separate upstream relay, controlled by the PCM, SO I would suspect engine not running (not seeing RPM) the PCM would NOT power heaters.

The sensors share a ground G101.
fuses involved are in cab #10 and PDC #17.
At ambient temperatures around 70°F, the resistance of the heating element is
approximately 6 ohms.
Attached Thumbnails
g101.JPG  
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When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #13 of 18 Old 12-24-2019, 10:16 AM Thread Starter
SpecialK2000
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I did not start replacing parts without diagnosing first. When I first got the P0135 and P0155 I checked to see if they were getting power and to see if the heating elements were working. I was incorrectly checking with the Engine Off though. I was following another post to run the check. I had some other electrical issues going on and all of the parts that I've changed were not overly expensive. I needed the parts anyway like a new battery, rebuilt alternator, ASD relay etc. New computer. At least I know all of that is good now.

I've checked every inch of the wires going from the battery to the O2 sensor. Battery to F17 in the PDC to the relay to the ASD to the 18 gage dark green going from the ASD to connector C107 pin 7 to the 20 gage dark green from pin 7 to terminal 1 on the O2 sensor connector. The power stops traveling somewhere between the C107 and the terminal 1. I checked the continuity of the wire and it passes. I know there is a splice in there that splits the power to both Bank 1 Sensor 1 and Bank 2 Sensor 1 but if something is wrong with the splice then ite wouldn't pass continuity. Plus I visually checked the splice and it looks as good as can be. I also removed the grounds at G101 and scuffed them clean and reattached. Also cleaned the other grounds in the engine compartment.

My MPG seem fine. The jeep runs perfectly. Smooth.

I'm stumped. Appreciate the help though.
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post #14 of 18 Old 12-25-2019, 05:46 AM
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"The power stops traveling somewhere between the C107 and the terminal 1. I checked the continuity of the wire and it passes. I know there is a splice in there that splits the power to both Bank 1 Sensor 1 and Bank 2 Sensor 1 but if something is wrong with the splice then ite wouldn't pass continuity." You would have continuity if moving the wire to measure it corrected the fault. If the fault is definitely between point A and B then replace the wire and redo the splices. Islip?? Lived in W.I. for a number of years. Cold up there. Merry Christmas
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post #15 of 18 Old 12-25-2019, 09:53 AM
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Trying to follow someone;s logic gets confusing - sounds like you have a grasp and have the diagrams - some thoughts -

following circuit A42 (DG wire) , at C107 is there good contact on both sides of connector?

When checking continuity on A42 from c107 #7 to terminal 1 of o2 sensors, the sensors are unplugged?


Have you opened or checked s121?

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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