Suzuki XL7 2007 Service Manual page 273

DTC P2270 or P2272
Diagnostic Instructions
• Perform the "Diagnostic System Check - Vehicle
Diagnostic Information: " prior to using this diagnostic
procedure.
• Review "Strategy Based Diagnosis: " for an overview
of the diagnostic approach.
• "Diagnostic Procedure Instructions - Vehicle
Diagnostic Information: " provides an overview of
each diagnostic category.
DTC Descriptors
DTC P2270: HO2S Signal Stuck Lean Bank 1 Sensor 2
DTC P2272: HO2S Signal Stuck Lean Bank 2 Sensor 2
Circuit Description
The engine control module (ECM) supplies a voltage
near 450 mV between the heated oxygen sensor
(HO2S) high signal circuit and the low reference circuit.
The HO2S varies the voltage over a range from about
1,000 mV when the exhaust is rich, down through about
10 mV when the exhaust is lean. The ECM monitors and
stores the HO2S voltage information. The ECM
evaluates the HO2S voltage samples in order to
determine the amount of time that the HO2S voltage was
out of range. The ECM compares the stored HO2S
voltage samples taken within each sample period and
determines if the majority of the samples are out of the
operating range. The ECM test for the following
conditions:
• The ECM monitors the HO2S voltage to determine if
the signal voltage goes above a predetermined
threshold within a certain amount of time. If the ECM
determines that the signal voltage remains below a
threshold, the ECM will command the fuel system rich
to determine if the HO2S signal voltage can be forced
above the threshold within a certain amount of time.
• The ECM monitors the HO2S voltage during power
enrichment to ensure that the signal voltage goes
above a predetermined threshold during power
enrichment.
Engine General Information and Diagnosis:
Conditions for Running the DTC
• Before the ECM can report DTC P2270 or P2272
failed, DTCs P0036, P0037, P0038, P0056, P0057,
P0058, P0137, P0138, P0140, P0141, P0157, P0158,
P0160, P0161, P0341, P0342, P0343, P0346, P0347,
P0348, P0366, P0367, P0368, P0391, P0392, P0393,
P0443, P0458, and P0459 must run and pass.
• DTCs P0461, P0462, P0463, P2066, P2067, and
P2068 are not set.
• The engine is operating.
• The ignition voltage is greater than 10 volts.
• The rear HO2S are at operating temperature for more
than 10 seconds.
• The long term fuel control is enabled.
• The mass air flow (MAF) sensor is more than 10 g/s.
• The MAF sensor is between 6-33 g/s for more than 3
seconds during the intrusive test.
• DTC P2270 and P2272 run continuously once the
above conditions are met for approximately 10
minutes when the fuel level is more than 12 percent.
• DTC P2270 and P2272 run continuously once the
above conditions are met for approximately 20
minutes when the fuel level is less 12 percent.
Conditions for Setting the DTC
The ECM detects that the rear HO2S voltage is less than
650 mV for more than 100 seconds, then an intrusive
test is performed. The ECM will enrich the fuel mixture
up to 30 percent and then wait for 10 seconds at 30
percent. The ECM detects that the HO2S voltage is less
than 650 mV during the intrusive test for greater than 4
seconds or for a cumulative of 50 seconds, the DTC
sets.
Action Taken when the DTC Sets
DTCs P2270 and P2272 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P2270 and P2272 are Type B DTCs.
Reference Information
Schematic Reference
"Engine Controls Schematics"
Connector End View Reference
• "Engine Control Module Connector End Views"
• "Engine Controls Connector End Views"
Electrical Information Reference
• "Circuit Testing: "
• "Connector Repairs: "
• "Testing for Intermittent Conditions and Poor
Connections: "
• "Wiring Repairs: "
1A-168