PO 137 code

The engine light came on in my truck . Go figure I'm waiting on my new one to come in at the dealer. Any way what does this code mean and what do i need to order to fix this . I've googled it and i'm thinking oxygen sensor but don't know which one. Anyone want to help me please.

 

P0137 - Oxygen Sensor Circuit Low Voltage (Bank 1 Sensor 2).

Bank #1 is the passenger side, Sensor # 2 is the sensor on the downstream side of the cat converter.
NOTE: It may not be the sensor itself. It could be an exhaust leak.

DESCRIPTION
In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a TWC (Three-Way Catalytic Converter) is used. For the most efficient use of the TWC, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric air-fuel level. For the purpose of helping the ECM to deliver accurate air-fuel ratio control, a Heated Oxygen (HO2) sensor is used.The HO2 sensor is located behind the TWC, and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low).When the air-fuel ratio becomes lean, the oxygen concentration in the exhaust gas is rich. The HO2 sensor informs the ECM that the post-TWC air-fuel ratio is lean (low voltage, i.e. less than 0.45 V).Conversely, when the air-fuel ratio is richer than the stoichiometric air-fuel level, the oxygen concentration in the exhaust gas becomes lean. The HO2 sensor informs the ECM that the post-TWC air-fuel ratio is rich (high voltage, i.e. more than 0.45 V). The HO2 sensor has the property of changing its output voltage drastically when the air-fuel ratio is close to the stoichiometric level.The ECM uses the supplementary information from the HO2 sensor to determine whether the air-fuel ratio after the TWC is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the HO2 sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air-fuel ratio control.

DTC Detection Conditions:

•Low voltage (open):
During active air-fuel ratio control, following conditions (a) and (b) met for certain period of time (2 trip detection logic)
(a) HO2 sensor voltage output less than 0.21 V
(b) Target air-fuel ratio rich

•High impedance:
Sensor impedance 15 kΩ or more for more than 90 seconds when ECM presumes sensor to being warmed up and operating normally (2 trip detection logic)

Trouble Areas:

•Open in HO2 sensor (bank 1, 2 sensor 2) circuit
•HO2 sensor (bank 1, 2 sensor 2)
•HO2 sensor heater (bank 1, 2 sensor 2)
•EFI relay
•Gas leakage from exhaust system

 

I had look under the truck and all the wiring looks good from the sensors , but I see a small exhaust leak . I made an appointment at the garage . Drove to work today and the engine light went out . Why would this be happening ? I use to work in a garage many years ago and lights never went out on their own . Has anyone had this happen before ? I'm still going to get my exhaust fixed .

 

I had a P0333, the dreaded knock sensor code that came and went. I hesitantly took it in for an inspection. It passed and the light came on as he was backing it out of the bay. Lol that turned out to be a loose connector.

Find and repair any exhaust leaks before you throw money into parts. I've also had a P0420 relating to the cat efficiency. That was caused by an exhaust leak, not the catalytic converter.

Good luck.

 

Thank goodness it was just a loose connection.
Mice and squirrel seem to love those things.
And it’s not an easy job to repair.

 

Tell me about it... My daughter did the actual replacing of the knock sensor. I am rather upset with myself for having gone through that for it only to be a loose connector.

 

Know this is a bit of an old thread but wanted to get some input. I have same code on 2TR-FE engine. I have replaced O2 sensor with a new Denso one, have no exhaust leaks, all connections and wires seem to be good and I am getting voltage numbers on the live data readings on the scan tool (voltage does go up and down with throttle input). Where should I check next?

 

p0137 can be a tricky one, the upstream A/F sensor can actually cause the downstream to read incorrectly.

If you have the freeze frame data from the P0137 share the voltage of the B1 S1 V when it fails.

 

Dug around a bit more by the O2 sensor connection and found this, under some electrical tape. This is the lead from the car to the sensor, the grey/white stripe lead is much larger diameter.

Just read on another post that the unshielded wire is a noise shield, seems like from that post it either is grounded, or should be. Does it come that way from the factory? Or should it be connected to something?

 

You need not do anything with that bit of shielding wire. That end is not connected and should not be connected. The other end is or should be connected to chassis ground. If you want to verify that it is connected to ground check it to ground with a DMM meter.

 

So to update…I ran around with the P0137 code for a bit, then used the scan tool to do a reset. Then it was code P0136. Still couldn’t figure it out so was going to make an appt at a local shop to see if they could help me troubleshoot it. Until then, I ran it that way for a few months. Just got in the car, now no codes (and the check engine light is not burnt out, lol). So she healed herself? Any ideas?

 

0136 is a malfunction on Bank 1 Sensor 2.
Maybe you had and Open or Short, and now the wiring has gotten shaken and making the correct contact?

 

Possibly. But I’ve had the codes for almost a year now, so if it were a loose connection I’m thinking it’d be a bit more intermittent. I’ll give it a look over this weekend to see if anything obvious has happened.