Having issue with 99 XLT V6 4.0 Ranger.

Real-time reading taken via FuzzyCar Iphone app and PLX Kiwi WiFi

Codes:
P1131
P0174
P0000
P0000

Oxygen voltage: bank 1, sensor 1 = 0.000volts
Oxygen voltage: bank 1, sensor 2 = 0.000volts

Oxygen voltage: bank 2, sensor 1 = 0.800volts


With ignition in the on position but engine not running I verified that 12volt was supplied to both Bank 1 sensors: Reading 12.3volts

I then ran the engine till warm and shut down and check for O2 sensor voltage at the O2 sensor connector (sensor unplugged) sensor side:
Oxygen voltage: bank 1, sensor 1 = 0.700volts
Oxygen voltage: bank 1, sensor 2 = 0.760volts

Once the truck warms up the drivability goes down, Once I clear the codes will run OK till check engine light comes on.

The MAF has been replaced and Oxygen sensor: bank 1, sensor 1 was too but I swapped back the old one and reading are the same. Then verified continuity from the O2 sensor to the ECU, all lines read under 4.5 ohms on DMM.

Could a bad ECU be the cause of this? (Dead bank 1 circuit) If so what are the steps or options to verify a bad ECU. Can the ECU be removed and tested localy?

 

My brother was over with his 99 3.0 Ranger so I plugged the PLX Kiwi WiFi into his truck and sure enough the real-time readings were:
Oxygen voltage: bank 1, sensor 1 = 0.700volts
Oxygen voltage: bank 1, sensor 2 = 0.760volts

Oxygen voltage: bank 2, sensor 1 = 0.780volts
-----------------------------------------------------------

Hooked my battery back up on My 99 4.0 now showing voltage for bank 1 sensor 1 but nothing on bank1 sensor 2:
Oxygen voltage: bank 1, sensor 1 = 0.700volts
Oxygen voltage: bank 1, sensor 2 = 0.000volts

Oxygen voltage: bank 2, sensor 1 = 0.800volts

Nothing was done other that disconnecting the negative battery terminal to reset the computer then hooking it back up after fifteen minuets.

No vacuum leaks found (sprayed carb cleaner) around all vacuum lines and upper and lower intake manifold gaskets.

Still no idea as to how to test the Engine control computer, other than buying new one. Or taking ethe truck to dealer.

 

These look like "snapshot" voltages taken at one moment in time. If the 11 and 21 sensors are monitored continuously, their output voltages will generally be in a constant state of change with readings falling between 0 and 1 volt (except in open loop conditions such as heavy acceleration or immediately after a cold start). The voltage from the 12 sensor after the cat will also vary although its frequency of change is much lower than that of the 2 front sensors.

The chances of the PCM causing any problems with the sensor voltage are near zero.

 

I believe these are real-time, yes a snap shot but setting is 1sec intervals. I only listed the highest voltage seen, there is never any change in the 0.000 voltage on bank 1, sensor 2. I checked the voltage at the sensor and with the DMM (pin tip lead poking through wire insulation.I see voltages between 0.090 and 0.750volts

The only time the truck runs well is after disconnecting the negative battery terminal to reset the computer then hooking it back up after fifteen minuets.

 

After looking things over this afternoon, checking connections and tracing wiring. Still found nothing. But hooked the battery back up and was seeing:
Oxygen voltage: bank 1, sensor 1 = 0.750volts
Oxygen voltage: bank 1, sensor 2 = 0.700volts

Oxygen voltage: bank 2, sensor 1 = 0.750volts

Let the truck idle for 20 min with no issues so took it down the road. Driving ok but no power when really stepping down on the gas peddle, slow smooth acceleration was fine but nothing happening for a few seconds when gas pressed to the floor truck just bugged down and slowly picks put speed. On the highway tried hard acceleration and both bank 1 O2 sensors dropped to zero volts after letting up on the gas bank 1 sensor 1 came back to 0.0700 range but sensor 2 now read zero stayed that way for three miles and then check engine light came on! Think I will go rent a fuel pressure tester in the morning other that that running out of Ideas!

 

Fuel pressure was low reading jumping around between 28 and 35psi. Much lower that the 52 to 72 psi that the manual states. Was able to take electric fuel pump off of the boat and run it inline and got the pressure up to a steady reading of 42psi.

Took the truck for a drive runs a little better and now seeing a voltage reading on all the O2 sensors:
Oxygen voltage: bank 1, sensor 1 = 0.750volts
Oxygen voltage: bank 1, sensor 2 = 0.600volts

Oxygen voltage: bank 2, sensor 1 = 0.750volts.

The voltage for bank1 sensor2 drops and stays at zero when the gas pedal is touched. I had changed the fuel filter a little over over a month ago so look like I need to change the fuel sending unit.

Question why would bank1 sensor 1 (Driver side cylinders) not be doing the same as bank1 sensor 2 (passenger side cylinders)?

 

Bank 1, Sensor 1 is passenger side, upsteam of cats, used for feedback fuel control
Bank 2, Sensor 1 is driver side, upsteam of cats, used for feedback fuel control

Bank 1, Sensor 2 is after the Y-pipe and some of the cats and is used primarily to judge the efficiency of the cats for OBDII. Despite its name, it monitors both PS and DS, not just PS (Bank 1).

 

excellent analysis!

 

Bad pressure reg on the fuel pump sending unit was cause. Replaced the fuel pump sending unit this morning and fuel pressure now steady reading of 65psi.

All voltage reading on O2 sensors are good:
Oxygen voltage: bank 1, sensor 1 = 0.750volts
Oxygen voltage: bank 1, sensor 2 = 0.680volts

Oxygen voltage: bank 2, sensor 1 = 0.750volts.

No codes after hour driving, much better throttle response.

 

I had a slight hesitation in the engine. I was looking for a vacuum leak. I scanned for codes P0171 Bank 1 system too lean. I sprayed carb cleaner in the vacuum hose to see if o2 sensor would change voltage it did. Than the rpm started racing 1800-2300 rpm. wont come down to normal. Now I check live data o2s b1s1 0.000 (v) o2s b1s2 0.005 (v). Would a bad o2 sensor make the rpm stay high or is there something else I should check.

 

I was having a similar problem. I have a 1995 ford ranger xlt 4.0. I had a lean code bank 1 P0171. I checked for vacuum leaks found one connected to the purge sensor. I fixed it. than the o2sensor upstream on bank 1 was reading 0 volts. I sprayed carb cleaner in the vacuum hose i just fixed a nice quick squert. The rpms went crazy stayed at 2000 rpm. I took it for a ride thinking the rpms would settle down, nope. So I thought the Throttle Position Sensor was bad TPS. I was determined to find out what was wrong.. 1st I unpluged the tps the rpms did come down but ran horrible. Checked live data bank 1 o2 sensor still said 0 volts. Than I found another vacuum leak next to the throttle body underneath a cover. I connected a new vacuum hose to it, runs much better, and i saw .005 vols on the o2 sensor. I am going to take it for a ride later. Hope that was the problem.Hope it helps others with this problem!!!

 

I went about 16 miles. No check engine light came on. It felt like it was hesitating slightly out of the exhaust. Next morning started it up check engine light was on. Took it for a ride aroud the block and when i stopped at a light the truck was shacking real bad. Like it wanted to take off. What can this be HELP!!!.

 

Do you have any tips on how to take out the Bank 1 sensor 1 on a 1995 ford ranger xlt 4.0 v6?

 

This is my first post. I think this thread may have something to do with a problem I am having with my Ranger. I was able to find a service bulletin regarding the o2 sensor. My OBD-ii scanner has no data from the O2 sensor. I am looking for someone outside the dealership that can put the 0.2 hours (according to the service bulletin) to recalibrate my PCM.

063000 ENGINE AND ENGINE COOLING: EXHAUST SYSTEM

RECORD_ID: 32133

Bulletin Number: 98315

Replacement Service Bulletin Number: N/A

NHTSA Item Number: 600598

Date Posted: 05-27-1998

Component Name: 063000 ENGINE AND ENGINE COOLING: EXHAUST SYSTEM

Make: FORD

Model: RANGER

Year: 1998

Date Added: 05-27-1998

Summary: ON SOME VEHICLES, THE SERVICE BAY DIAGNOSTIC SYSTEM (SBDS) AND/OR NEW GENERATION STAR (NGS) TESTER MAY NOT BE ABLE TO READ THE SIGNAL FROM THE HEATED OXYGEN SENSOR (HO2S). *YC