Alec

Hey everyone.

I recently started getting code P0155: O2 sensor 2/1 heater circuit high. I inspected the sensor and wires and found some damage from my RIPP headers. I replaced the sensor and repaired the wires and am still getting the code. I've read that this code often leads to replacement of the PCM to fix it. I have the RIPP s/c and am highly modified, so getting it warrantied would be difficult. I don't want to replace the PCM just for this code.

DISCLAIMER: Helping me with this issue will incur no liability, I take any and all responsibility for tampering with emissions devices.

With that out of the way....I live in Texas and I know my exhaust heats up quickly. So I am not concerned with the emissions implications of altering the heater circuit. I am, however, concerned with the state inspection and OBD check. I am going to check as much wiring as I can and also all the fuses. Are there any specific fuses that may be an issue?

Also, what values is the computer expecting to see? Can I spoof the signal somehow? Remember, this is only the heater circuit, not the sensor circuit. Oh, and when wiring the new sensor, the instructions said it didn't matter which way the 2 white wires were connected. Is this true? Is one "white" wire the power and the other the ground? If so, in the stock harness, which is which, the green and black wires?

I also emailed RIPP to see if there is anything they can do for me on the computer end.

Thanks for all your help.

Alec

Bump for the weekday crowd. Any help would be appreciated.

ronjenx

One question to get out of the way is: Which O2 sensor do you believe is 2/1

Alec

Driver front? Bank 2, sensor 1

ronjenx

Yes. Left upper sensor. I asked because on many occasions people have gone for the wrong sensor.

Are you handy with a digital multimeter?

Alec

I have a decent meter. I just didn't know what the values are supposed to be.

33 williys 77

P0155 Oxygen Sensor Heater Performance (Bank 2, Sensor 1)

“Slow response” indicates a “lazy” sensor which should be replaced. “Heater performance” errors involve the built in electric sensor heater which gets it into operating mode more quickly.

Bank #2 on a 3.8 is on the drivers side (Bank #2).
Sensor 1 is upstream (before the cat) and sensor 2 is downstream (after the cat).
While the sensor itself may be the same, connector key-ways and wire lengths are different between upstream and downstream O2 sensor

Disconnect the 2/1 O2 Sensor harness connector.
Measure the resistance of the O2 Heater Element across the O2 Sensor connector between the O2 Heater Control terminal and the O2 Heater ground terminal. NOTE: O2 Heater Element resistance values should be measured at 70°F (21.1°C). The resistance value will vary with different temperature values.

The resistance of the O2 Sensor Heater Element is between 2.0 and 30.0 ohms if not replace the O2 Sensor.
If you have 2.0 and 30.0 ohms then check for high resistance or open in the sensor Control circuit.


33

Rex08

I have a 2010 and just had to take mine in for a recall on the oxygen sensor.... Might help

Alec

I looked at the recall and I don't think it applies to me. I checked the sensor heater resistance and it is 2.3 ohms. So I guess next step would be check the two pins in question at the computer for circuit resistance and if it's vastly different look in the harness? I've never looked at the connections for the jeep's computer, but have done other vehicles. So I guess I'd need to know which connector to look at and which pins. If the harness is ok then I guess it's the computer.

So, which connector do I have to unplug and probe? Pins? THANKS!!!!

33 williys 77

Have you ever used a cable tracer HF has one for phone line the RF output is very small and should not hurt the computer
I have used it on other vehicles with no problems, if worried remove batt cables and the connector to the computer.
HF has one for around 20 bucks, every tool box should have one of these! HF web site and plug in Cable Tracker in the search box

Designed for use with telephone lines, alarm cables, computer cables, intercom lines, speaker wires, and thermostat wiring
Includes transmitter, receiver, #RJ11 telephone jack plug, two 9 volt batteries, users manual and carrying case