Hi All,

Does anyone know where the Censor for code #P0139 is located? I already replaced the 2 up stream and the 2 down stream, how many more are there? I just did a full tune up and then the engine light came on after replacing the battery a few days later? The Code comes up P0139

HELP?

Thanks,
Ray

 

Welcome to DF KIDMAN! That codes a O2 Sensor Slow Response Code... Ill move this thread over to the 3rd Gen Ram Section for better input. Those guys and gals maybe able to give ya a better idea of whats going on with it. Good luck and I hope you get this resolved!

 

Thanks its a pain in the A**!

 

I got that code on my 03. I was able to hook up a Super Chips 3815 programmer and watch my 02 sensors in action. In my case I noticed that the down stream 02 sensor was basically burned out. After replacing it I no longer got that code. I see that you replaced yours and your code came back. I really dont have an answer for you unless you can get some data from your sensors be it a programmer or from another source.

You can see here I reved the engine and the B1 S2 sensor which is the down stream sensor never changed. It was basically just burned out. After I replaced I retested the sensor and it moved up and down in voltage and trim percent and I never got the code again...

 

Thanks for the response I should have also mentioned I have a 4.7 motor.

I don't know where I can locate a programmer like you mentioned. The only device I know about are the diagnostic box parts America lets you "borrow" to go run the codes? P0139 doesn't come up for the 2 upstream or 2 down stream? I just want to know where the Censor is for P0139 is located on my truck?

Anyone?

 

PO139 is a slow response from your downstream o2 sensor.

https://dodgeforum.com/forum/3rd-gen...ave-proof.html

https://dodgeforum.com/forum/3rd-gen...-for-this.html

 

Thanks, So P0139 = 1/2 O2S Slow Response

So this is bank1 sensor2 = Driver side After the cat?

Thanks if so I replaced it about 5 months ago?

 

I see that. Check your wires. look for shorts,opens or high resistance. If that dont work find a garage that has a good Snap-On OBD2 Scanner. They can look at the voltages of your O2 sensor in action. If not you may have to bite the bullet and take it to a dealer if its bugging you that much...

 

You may not be an electronics buff like me, but if you are this may help...

How can I test my O2 sensor?

They can be tested both in the car and out. If you have a high impedence volt meter, the procedure is fairly simple. It will help you to have some background on the way the sensor does it's job. Read how does an O2 sensor work first. Testing O2 sensors that are installed

The engine must first be fully warm. If you have a defective thermostat, this test may not be possible due to a minimum temperature required for closed loop operation. Attach the positive lead of a high impedence DC voltmeter to the Oxygen sensor output wire. This wire should remain attached to the computer. You will have to back probe the connection or use a jumper wire to get access. The negative lead should be attached to a good clean ground on the engine block or accessory bracket. Cheap voltmeters will not give accurate results because they load down the circuit and absorb the voltage that they are attempting to measure. A acceptable value is 1,000,000 ohms/volt or more on the DC voltage. Most (if not all) digital voltmeters meet this need. Few (if any) non-powered analog (needle style) voltmeters do. Check the specs for your meter to find out. Set your meter to look for 1 volt DC. Many late model cars use a heated O2 sensor. These have either two or three wires instead of one. Heated sensors will have 12 volts on one lead, ground on the other, and the sensor signal on the third. If you have two or three wires, use a 15 or higher volt scale on the meter until you know which is the sensor output wire. When you turn the key on, do not start the engine. You should see a change in voltage on the meter in most late model cars. If not, check your connections. Next, check your leads to make sure you won't wrap up any wires in the belts, etc. then start the engine. You should run the engine above 2000 rpm for two minutes to warm the O2 sensor and try to get into closed loop. Closed loop operation is indicated by the sensor showing several cross counts per second. It may help to rev the engine between idle and about 3000 rpm several times. The computer recognizes the sensor as hot and active once there are several cross counts. You are looking for voltage to go above and below 0.45 volts. If you see less than 0.2 and more than 0.7 volts and the value changes rapidly, you are through, your sensor is good. If not, is it steady high (> 0.45) near 0.45 or steady low (< 0.45). If the voltage is near the middle, you may not be hot yet. Run the engine above 2000 rpm again. If the reading is steady low, add richness by partially closing the choke or adding some propane through the air intake. Be very careful if you work with any extra gasoline, you can easily be burned or have an explosion. If the voltage now rises above 0.7 to 0.9, and you can change it at will by changing the extra fuel, the O2 sensor is usually good. If the voltage is steady high, create a vacuum leak. Try pulling the PCV valve out of it's hose and letting air enter. You can also use the power brake vacuum supply hose. If this drives the voltage to 0.2 to 0.3 or less and you can control it at will by opening and closing the vacuum leak, the sensor is usually good. If you are not able to make a change either way, stop the engine, unhook the sensor wire from the computer harness, and reattach your voltmeter to the sensor output wire. Repeat the rich and lean steps. If you can't get the sensor voltage to change, and you have a good sensor and ground connection, try heating it once more. Repeat the rich and lean steps. If still no voltage or fixed voltage, you have a bad sensor. If you are not getting a voltage and the car has been running rich lately, the sensor may be carbon fouled. It is sometimes possible to clean a sensor in the car. Do this by unplugging the sensor harness, warming up the engine, and creating a lean condition at about 2000 rpm for 1 or 2 minutes. Create a big enough vacuum leak so that the engine begins to slow down. The extra heat will clean it off if possible. If not, it was dead anyway, no loss. In either case, fix the cause of the rich mixture and retest. If you don't, the new sensor will fail. Testing O2 sensors on the workbench.

Use a high impedence DC voltmeter as above. Clamp the sensor in a vice, or use a plier or vice-grip to hold it. Clamp your negative voltmeter lead to the case, and the positive to the output wire. Use a propane torch set to high and the inner blue flame tip to heat the fluted or perforated area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems. ANY O2 sensor that will generate 0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. This will calibrate your evaluation skills and save you money in the future. There is almost always *no* benefit in replacing an oxygen sensor that will pass the test in the first line of this paragraph.

 

WOW thats HEAVY DUTY!! Um uhhhh...