2010 Cadillac Truck SRX AWD V6-3.0L Page 1490

2010 Cadillac Truck SRX AWD V6-3.0L Page 1490

* Restricted Exhaust (See: Engine, Cooling and Exhaust/Exhaust System/Testing and Inspection/Restricted Exhaust)

* Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LF1) (See: Powertrain Management/Computers and Control Systems/Oxygen

Sensor/Service and Repair/Heated Oxygen Sensor Replacement - Bank 1 Sensor 2)

* Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1) (See: Powertrain Management/Computers and Control Systems/Oxygen

Sensor/Service and Repair/Heated Oxygen Sensor Replacement - Bank 2 Sensor 2)

* Catalytic Converter Replacement - Left Side (LF1) (See: Engine, Cooling and Exhaust/Exhaust System/Catalytic Converter/Service and

Repair/Catalytic Converter Replacement - Left Side)

* Catalytic Converter Replacement - Right Side (LF1) (See: Engine, Cooling and Exhaust/Exhaust System/Catalytic Converter/Service and

Repair/Catalytic Converter Replacement - Right Side)

P0430

DTC P0420 or P0430

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions)provides an overview of each diagnostic category.

DTC Descriptor

DTC P0420

- Catalyst System Low Efficiency Bank 1

DTC P0430

- Catalyst System Low Efficiency Bank 2

Circuit/System Description

A 3-way catalytic converter (TWC) controls emissions of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). The catalyst

within the converter promotes a chemical reaction, which oxidizes the HC and the CO that are present in the exhaust gas. This process converts the

HC and the CO into water vapor and carbon dioxide (CO2), and reduces the NOx, converting the NOx into nitrogen. The catalytic converter also

stores oxygen. The engine control module (ECM) monitors this process by using a heated oxygen sensor (HO2S) that is in the exhaust stream after

the TWC. The HO2S 2 produces an output signal that the ECM uses to calculate the oxygen storage capacity of the catalyst. This indicates the

ability of the catalyst to convert the exhaust emissions efficiently. The ECM monitors the efficiency of the catalyst by allowing the catalyst to heat,

then wait for a stabilization period while the engine is idling. The ECM then adds and removes fuel while monitoring the HO2S 2. When the

catalyst is functioning properly, the HO2S 2 response to the extra fuel is slow compared to the response of the HO2S 1, which is located before the

TWC. When the HO2S 2 response is near that of the HO2S 1, the oxygen storage capability and efficiency of the catalyst may be degraded below

an acceptable threshold.

Conditions for Running the DTC

LF1

* DTCs P000A, P000B, P000C, P000D, 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, P0128, P0130, P0131, P0132, P0133, P0135,

P0137, P0138, P013A, P013C, P013E, P0140, P0141, P014A, P0150, 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, or P2273 is not set.

* Before the ECM performs the idle test, the vehicle must be driven under the following conditions:

- The engine speed is greater than 915 RPM

- The engine run time is greater than a calibrated value

- Both conditions exist for greater than 15 seconds

* The throttle is in the rest position.

* The intake air temperature (IAT) is between -20 to +250掳C (-4 to +482掳F).

* The ignition voltage is greater than 11 volts.

* The engine coolant temperature (ECT) is between 40-127掳C (104-261掳F).

* The barometric pressure (BARO) is greater than 70 kPa.

* The engine has been idling less than 50 seconds.

* The vehicle speed is less than 2 km/h (1 mph).

* The short term fuel trim is learned.

* The air flow into the engine is between 3-13 g/s.

* The EVAP purge concentration is learned.

* The catalytic converter (TWC) calculated temperature is between 450-250掳C (842-1,742掳F).