Suzuki XL7 2007 Service Manual page 214

1A-109 Engine General Information and Diagnosis:
Repair Instructions
Perform the Perform the "Diagnostic Repair Verification -
Vehicle Diagnostic Information: " after completing the
diagnostic procedure.
• "Camshaft Position Sensor Replacement - Bank 2
(Left Side) Exhaust: "
• "Camshaft Position Sensor Replacement - Bank 2
(Left Side) Intake: "
• "Camshaft Position Sensor Replacement - Bank 1
(Right Side) Exhaust: "
• "Camshaft Position Sensor Replacement - Bank 1
(Right Side) Intake: "
• "Control Module References: " for engine control
module replacement, setup, and programming
DTC P0420 or P0430
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 P0420: Catalyst System Low Efficiency Bank 1
DTC P0430: Catalyst System Low Efficiency Bank 2
Circuit/System Description
In order to maintain a reasonably low emission level of
hydrocarbons (HC), carbon monoxide (CO), and oxides
of nitrogen (NOx) a 3-way catalytic converter (TWC) is
used. The catalyst within the converter promotes a
chemical reaction that oxidizes the HC and CO present
in the exhaust gas. This reaction converts the gases into
harmless water vapor and carbon dioxide. The catalyst
also reduces the NOx, converting the NOx into nitrogen.
The engine control module (ECM) monitors this process
using the post catalyst heated oxygen sensor (HO2S)
signal. The post-catalyst HO2S located in the exhaust
stream after the TWC, produces an output signal that
indicates the oxygen storage capacity of the catalyst.
The oxygen storage capacity (OSC) determines the
ability of the catalyst to convert the exhaust emissions
effectively. If the catalyst is functioning correctly, the
post-catalyst HO2S signal will be far less active than the
signal produced by the pre-catalyst HO2S.
To determine OSC, the ECM commands a rich air/fuel
mixture until all oxygen is removed from the catalyst.
The ECM then commands a lean air/fuel mixture and
monitors the rear heated oxygen sensors to calculate the
oxygen storage capacity. The catalyst is operated in this
mode until one of the following conditions occur:
• The oxygen stored in the catalyst exceeds a
calibrated threshold, which is determined from the
rear HO2S signal.
• The rear HO2S indicates the catalyst to be completely
saturated with oxygen, which is determined from the
rear HO2S signal.
Conditions for Running the DTC
• Before the ECM can report DTC P0420 or P0430
failed, DTCs P0030, P0031, P0032, P0036, P0037,
P0038, P0050, P0051, P0052, P0056, P0057, P0058,
P0100, P0101, P0102, P0103, P0121, P0122, P0123,
P0131, P0132, P0133, P0135, P0137, P0138, P0140,
P0141, P0151, P0152, P0153, P0155, P0157, P0158,
P0160, P0161, P0221, P0222, P0223, P0335, P0336,
P0338, P2096, P2097, P2098, P2099, P2195, P2196,
P2197, P2198, P2232, P2235, P2237, P2240, P2243,
P2247, P2251, P2254, P2270, P2271, P2272, P2273,
P2297, P2298, P2626, and P2629 must run and pass.
• DTCs P0010, P0011, P0013, P0014, P0020, P0021,
P0023, P0024, P0030, P0031, P0032, P0050, P0051,
P0052, P0100, P0101, P0102, P0103, P0116, P0117,
P0118, P0119, P0121, P0122, P0123, P0125, P0131,
P0132, P0133, P0135, P0137, P0138, P0140, P0141,
P0151, P0152, P0153, P0155, P0157, P0158, P0160,
P0161, P0221, P0222, P0223, P0300, P0301-P0306,
P0443, P0455, P0458, P0459, P0496, P2088, P2089,
P2090, P2091, P2092, P2093, P2094, P2095, P2096,
P2097, P2098, P2099, P2100, P2101, P2107, P2119,
P2122, P2123, P2127, P2128, P2138, P2176, P2177,
P2178, P2179, P2180, P2187, P2188, P2189, P2190,
P2232, P2235, P2270, P2271, P2272, and P2273 are
not set.
• The engine speed is 1040-2760 RPM.
• The engine load is 15-50%.
• The air flow into the engine is between 5-60 g/s and
steady.
• The engine intake air temperature (IAT) at engine
start-up is more than −10°C (14°F).
• The engine is operating for more than 7 minutes.
• The engine is operating in Closed Loop.
• The calculated TWC temperature is between 400-
850°C (752-1,562°F) and steady.
• The above conditions exist for approximately 17
minutes.
• DTCs P0420 and P0430 run once a drive cycle. The
ECM will attempt to run this diagnostic up to 3 times a
drive cycle.