Specifications

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Data Parameters Engine Parameters
O2S (LAMBDA) CTRL CTP (IDLE) MEAN
Range: _________________________________________________________ 0 to 100%
Used on HFM systems. This is the average short-term fuel metering correction required at idle to
maintain a stoichiometric (14.7:1), or 1.0 Lambda, air-fuel ratio. The display shows the correction
factor as a percentage of total injector on time.
O2S (LAMBDA) CTRL PART. LOAD MEAN
Range: _________________________________________________________ 0 to 100%
Used on HFM systems. This parameter represents the average Lambda short-term fuel
correction required at partial load to maintain a stoichiometric (14.7:1), or 1.0 Lambda, air-fuel
ratio. The display shows the correction factor as a percentage of total injector on time.
O2S 1 HEATER
O2S 1 (BEFORE TWC) HEATER
O2S 2 HEATER
Range: __________________________________________________________ ON/OFF
Used on HFM, ME10 and ME20 systems. These parameters display the state of the upstream
oxygen sensor (O2S) heater circuits. A reading of ON indicates the heater circuit is energized
and OFF indicates power is not being applied to the heater.
O2S 1 VOLTAGE
O2S 2 VOLTAGE
Range: ___________________________________________________ –200 to 1000 mV
Used on DM2 and HFM systems. These parameters are the feedback voltage signal delivered to
the ECU by the oxygen sensors (O2S) on cylinder banks number one and two. During closed
loop the value should switch rapidly from below 450 mV to above 450 mV.
O2S CONT.SHIFT MILEAGE COUNTER
Range: __________________________________________________________ variable
Used on HFM systems. This is a count of the mileage driven since the oxygen sensor (O2S) was
replaced in mph or kph. When the elapsed mileage reaches the O2S replacement interval, the
ECU turns on a warning lamp on the dash. The counter must be reset when the O2S is replaced.
O2S DOWNSTREAM CAT, CYL 1 to 12
O2S UPSTREAM CAT, CYL 1 to 12
O2S DOWNSTREAM CAT, LEFT
O2S DOWNSTREAM CAT, RIGHT
O2S UPSTREAM CAT, LEFT
O2S UPSTREAM CAT, RIGHT
Range: ________________________________________________ READY/NOT READY
Used on ME27 and ME28 systems. These parameters indicate whether the oxygen sensor
(O2S) is at operating temperature, and ready or not ready to send reliable data. The “1 to 12" in
the some of the names indicate up to twelve separate parameters, one for each cylinder.
O2S HEATER AFTER TWC
O2S HEATER BEFORE TWC
Range: __________________________________________________________ ON/OFF
Used on ME10 and ME20 systems. These parameters show the state of the upstream and
downstream oxygen sensor (O2S) heater circuits. A reading of ON indicates the heater circuit is
energized and a reading of OFF indicates power is not applied.