B3000 SE Regular Cab 4WD V6-3.0L OHV (1998)
Example: A vehicle with a MIL concern indicating KOER DTCs (P01351 P0155) both front HO2S heater circuit failure codes and no other DTCs
set. The most likely cause of this concern would be something common to both heater circuits such as the heater power supply. Always review the
wiring diagrams to find circuits common to both sensors. In the the figure shown, splice A would be a good place to start your inspection.
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NGS & WDS HO2S PIDS With 0 Values: NGS and WDS may display PIDS for more HO2S than a vehicle is equipped with. If the scan-tool shows
a value of 0 for an HO2S PID, it may not have that HO2S. The NGS figure shows a 4-cylinder engine with PIDS for two upstream and two
down-stream HO2S and the unused HO2S show 0.0 volts.
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HO2S Measure Oxygen Content Not Unburned Fuel: Misfires result in lean HO2S readings. When a cylinder misfires, raw fuel and oxygen are
passed into the exhaust. This additional air makes the exhaust lean. For an HO2S to indicate a rich condition, the fuel would have to burn in the
combustion chamber along with the oxygen.
