No voltage output from all oxygen sensors

TRINITY58

MEMBER
1998 FORD EXPLORER
4.0L
6 CYL
2WD
MANUAL
224,868 MILES

Hello,

I have a problem with no voltage output from all (3) oxygen sensors when doing a live scan. The code was P0133, O2 Sensor Circuit Slow Response Bank 1 Sensor 1. I have replaced all 3 oxygen sensors, and still do not show voltage output. The engine is running in closed loop almost immediately after start up.

However, since changing out the O2 sensors, the P0133 code has gone away and now P0305, misfire on #5, is showing. The engine seems to be running rich, idling a little rough and slightly stumbling under 2000 rpm. On the highway it runs great. I have a DVM and a test light, but need some expert troubleshooting guidance. I recently replaced all gaskets from the lower intake up, due to a coolant leak and would sure like to get her purring again.

Here is the freeze frame data:

VIN: 1FMYU22X0WUB25798
Trouble Code Triggering Freeze Frame:
P0305: Cylinder 5 Misfire Detected
Freeze Frame Data:
• PID : Description : Value
• 03 : Fuel System Status : Closed loop - using all oxygen sensor(s) as feedback
for fuel control
• 04 : Calculated Engine Load Value : 46.3 %
• 05 : Engine Coolant Temperature : 84 °C, 183 °F
• 06 : Short Term Fuel Trim Bank 1 : 0.0 %
• 07 : Long Term Fuel Trim Bank 1 : 10.2 %
• 08 : Short Term Fuel Trim Bank 2 : -7.0 %
• 09 : Long Term Fuel Trim Bank 2 : 3.1 %
• 0C : Engine RPM : 1887 rpm
• 0D : Vehicle Speed : 53 km/h, 33 MPH

Thank you for your time!

3 Replies

BMDOUBLE

MECHANIC
1,139 POSTS

From the freeze frame data it seems as though it is running a little lean on bank 1. Has the fuel pressure been verified to be 35-45 psi? If not I would start here. Also, while monitoring the o2 sensor voltage, spray the inside of the intake tube with carburetor cleaner or brake clean. The voltage should spike up instantly, if it does, the o2 sensors are operating normally and you are sure to be chasing a lean condition. Have the plug wires been replaced? If so make sure the wires at the coil are situated in the right way because they are position 1-2-3 on one side and 4-6-5 on the other, which is ridiculous for Ford to have done but it is what it is! Let us know what you find!