96 850 Turbo Wagon Pulling P0131 and P0137 Codes - Really Need Some Help On This

[clarkr]

Hi all,
Need some help determining how to diagnose some codes I am pulling. It has been going on for a couple of years now. Intermittant Check Engine codes P0137 and P0131.

1996 Volvo 850 Turbo wagon
VIN: YV1LW5720T2247599
Engine Type: 57 - 2.3L 5 cylinder
Front wheel drive
Mileage: 205 K

Pulled this info from a code reader:

Code P0137 - O2 Sensor - Circuit Low Voltage
Bank 1 Sensor 2

Code P0131 - O2 Sensor - Circuit Low Voltage
Bank 1 Sensor 1

Freeze frame from code reader I pulled the next day. Not sure what all this means if anything:
DTCFRZF P0131
Fuel System 1 OL
Fuel System 2 N/A
Load_Percentage 2.0
ECT °C 82
SHRTFT  1 (%)
Long FT 1 (%) 0.0
RPM (1 min) 800
VSS (Km/h  18

Long term symptoms:
I seem to be getting the CEL after driving around 100-120 miles mostly on trips but eventually when I reach this milestone to set the codes .  Most of the milage is highway driving 55-65 mph. Sometimes comes on when reducing speed going through small towns or slowing for stop signs or variations of speed on highway. Also will hit the CEL after driving about that mileage over time with variation of mostly highway and in town driving.

I need some info on how to attack this. Is it O2 sensors; relays; electronics going to injectors; fuel pump; fuel pump rag filter; computer or some other malfunction? Can't keep throwing money at it to find a solution without an educated guess on where the problem/s are.

Here is what I have done so far:
1. New plug wires and plugs
2. New distributor cap and rotor
3. New Bosch upstream O2 sensor
4. Cleaned all injectors - Pulled out of fuel rail. Made tool to spray carb cleaner through injectors when injector is opened with elecrical charge. All injectors worked good when sprayed carb cleaner through them as supposed to do.
5. New injector o-rings top and bottom. Did not replace fuel rail o-rings for injectors or seals on intake manifold. All seemed fine.
6. Brand new inline Gas Filter
7. Brand new Air Filter
8. Not sure of the cat but no exhaust leaks or problems that I can determine.

I am at a loss as to where to go with this. Why would it take so long to trip the codes?

Engine runs great and turbo working as it should. Getting 24-25 mpg on mostly highway driving.

Anyone? Let me know if you need more info on something.

Thanks for your help in advance,
Clark

[wmartinlsmith]

The code P0137: O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2) points out a fault in the oxygen sensor located after the catalytic converter, and most likely is caused by issues in the sensor itself, wiring problems, or exhaust leaks.

 

P0137 quick overview

Meaning	P0137: O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)
Is it serious?	Yes, it can lead to poor fuel efficiency, increased emissions, and potential damage to the catalytic converter if not addressed.
Possible causes	– Faulty oxygen sensor – Wiring or connector issues related to the oxygen sensor – Exhaust leaks, especially between the O2 sensors and the catalytic converter – Faulty Mass Air Flow (MAF) sensor – Use of non-OEM or incompatible oxygen sensors
How to diagnose?	1. Read the fault codes using an OBD-II scanner to confirm P0137 and any other related codes.  2. Visually inspect the wiring and connectors associated with the oxygen sensor for any signs of damage, corrosion, or disconnection.  3. Check for any exhaust leaks, especially in the area between the oxygen sensors and the catalytic converter.  4. If the vehicle has multiple banks, consider swapping the O2 sensors between them to see if the fault follows the sensor or stays with the bank.  5. Use a diagnostic tool to monitor the O2 sensor’s voltage. If it’s consistently low, the sensor might be faulty.  6. Force the system to run rich using propane or another method and monitor the O2 sensor’s response.  7. If suspecting a Mass Air Flow (MAF) sensor issue, test with a known good MAF sensor. 8. Always check for any recalls or Technical Service Bulletins (TSBs) related to the O2 sensors or associated systems for the specific vehicle model.

make sure you installed, may have to be OEM O2 sensors. check the MAF sensor, the OEM BOSCH piece is not being manufactured anymore as far as I know. if the wiring is coroded any where causing resistence, even the smallest bit, it can cause a volt drop leading to inconsitant voltage. and look for pin hole leaks before the cat. 

 

 

according to. 

https://www.iamcarhacker.com/fix-p0137/

[clarkr]

16 hours ago, wmartinlsmith said:

The code P0137: O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2) points out a fault in the oxygen sensor located after the catalytic converter, and most likely is caused by issues in the sensor itself, wiring problems, or exhaust leaks.

 

P0137 quick overview

Meaning	P0137: O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)
Is it serious?	Yes, it can lead to poor fuel efficiency, increased emissions, and potential damage to the catalytic converter if not addressed.
Possible causes	– Faulty oxygen sensor – Wiring or connector issues related to the oxygen sensor – Exhaust leaks, especially between the O2 sensors and the catalytic converter – Faulty Mass Air Flow (MAF) sensor – Use of non-OEM or incompatible oxygen sensors
How to diagnose?	1. Read the fault codes using an OBD-II scanner to confirm P0137 and any other related codes.  2. Visually inspect the wiring and connectors associated with the oxygen sensor for any signs of damage, corrosion, or disconnection.  3. Check for any exhaust leaks, especially in the area between the oxygen sensors and the catalytic converter.  4. If the vehicle has multiple banks, consider swapping the O2 sensors between them to see if the fault follows the sensor or stays with the bank.  5. Use a diagnostic tool to monitor the O2 sensor’s voltage. If it’s consistently low, the sensor might be faulty.  6. Force the system to run rich using propane or another method and monitor the O2 sensor’s response.  7. If suspecting a Mass Air Flow (MAF) sensor issue, test with a known good MAF sensor. 8. Always check for any recalls or Technical Service Bulletins (TSBs) related to the O2 sensors or associated systems for the specific vehicle model.

make sure you installed, may have to be OEM O2 sensors. check the MAF sensor, the OEM BOSCH piece is not being manufactured anymore as far as I know. if the wiring is coroded any where causing resistence, even the smallest bit, it can cause a volt drop leading to inconsitant voltage. and look for pin hole leaks before the cat. 

 

Thank you. This is a real help. It gives me something to start with. You say that Bosch is not making the MAF sensors anymore? If not what is a premium brand to go with. Will have to do some tracing to check for corrosion.

The weather has dropped off the table here so next reasonably warm day will do some investigating on this. GREAT job.

Thanks, Clark

Edited December 5, 2024 by clarkr