2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1347
- 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).
* The engine is operating in Closed Loop.
* The transmission is not in P/N (automatic transmission only).
This diagnostic attempts one test during each valid idle period once the above conditions have been met. This diagnostic attempts up to 8 tests
during each drive cycle.
LAU
* DTCs P0010, P0011, P0013, P0014, P0030, P0031, P0032, P0036, P0053, P0097, P0098, P0100, P0101, P0102, P0103, P0106, P0107,
P0108, P0117, P0118, P0121, P0122, P0123, P0128, P0130, P0131, P0132, P0133, P0135, P0137, P0138, P013A, P0140, P0141, P0221,
P0222, P0223, P0300, P0335, P0336, P0341, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P0458, P0459, P0461, P0496, P0502,
P0506, P0507, P167A, P2088, P2089, P2090, P2091, P2096, P2097, P2176, P2195, P2196, P2232, P2237, P2243, P2251, P2270, P2271,
P2297, P2626 are not set.
* The engine speed is between 1,040-2,760 RPM.
* The engine load is between 15-50 percent.
* The engine is operating in Closed Loop.
* The calculated exhaust mass gas flow is between 5-56 g/sec, and stable.
* The calculated catalyst temperature is between 400-850掳C (852-1,562掳F).
* The intake air temperature (IAT) is greater than -15 (5掳F).
This diagnostic attempts one test during each period when the above conditions have been met. This diagnostic attempts up to 4 tests during each
drive cycle.
Conditions for Setting the DTC
The ECM determines that the efficiency of the catalyst has degraded below a calibrated threshold.
Action Taken When the DTC Sets
DTC P0420 and P0430 are Type A DTCs.
