2010 Cadillac CTS Sedan AWD V6-3.0L Page 1898

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1898

* 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 Descriptors

DTC P2177

- Fuel Trim System Lean at Cruise or Acceleration Bank 1

DTC P2179

- Fuel Trim System Lean at Cruise or Acceleration Bank 2

DTC P2187

- Fuel Trim System Lean at Idle Bank 1

DTC P2189

- Fuel Trim System Lean at Idle Bank 2

Circuit Description

The fuel trim control system monitors the range of the air/fuel ratio in order to maintain the desired ratio for optimum emissions performance. The

system performs tests during certain operating conditions to detect unmetered air or unmetered fuel. The fuel trim control system operation can be

observed by monitoring the scan tool Short Term and Long Term Fuel Trim parameters.

Conditions for Running the DTC

P2177 or P2179

* Before the ECM can report DTC P2177 or P2179, failed, DTCs P000A, P000B, P000C, P000D, P0008, P0009, P0010, P0011, P0013,

P0014, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0101, P0121, P0122, P0123, P0133, P0153, P0201, P0202, P0203,

P0204, P0205, P0206, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0300, P0301, P0302,

P0303, P0304, P0305, P0306, P0335, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2068 P2088, P2089, P2090, P2091,

P2092, P2093, P2094, P2095 P2146, P2149, P2152, P2155, P216A, and P216D must run and pass.

* The engine speed is between 1,200-3,400 RPM.

* The engine load is between 13-40 %.

* The throttle angle is less than 100 %.

* The cold start fuel control is not active.

* The Closed Loop fuel control is enabled.

* The engine is not in decel fuel cut-off.

* The intake air temperature (IAT) is colder than 60掳C (140掳F).

* The calculated amount of fuel metered into the engine is greater than 700 g.

* DTC P2177 and P2179 run continuously once the above conditions are met for approximately 300 s, after Closed Loop fuel control is

enabled.

P2187 or P2189

* Before the ECM can report DTC P2187 or P2189, failed, DTCs P000A, P000B, P000C, P000D, P0008, P0009, P0010, P0011, P0013,

P0014, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0101, P0121, P0122, P0123, P0133, P0153, P0201, P0202, P0203,

P0204, P0205, P0206, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0300, P0301, P0302,

P0303, P0304, P0305, P0306, P0335, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2068 P2088, P2089, P2090, P2091,

P2092, P2093, P2094, P2095 P2146, P2149, P2152, P2155, P216A, and P216D must run and pass.

* The engine speed is between 519-1,001 RPM.

* The engine load is between 0-24 %.

* The throttle angle is less than 100 %.

* The cold start fuel control is not active.

* The Closed Loop fuel control is enabled.

* The engine is not in decel fuel cut-off.

* The engine coolant temperature (ECT) is warmer than 60掳C (140掳F).

* The intake air temperature (IAT) is colder than 61掳C (142掳F).

* The calculated amount of fuel metered into the engine is greater than 700 g.

* DTC P2187 and P2189 run continuously once the above conditions are met for approximately 300 s, after Closed Loop fuel control is

enabled.

Conditions for Setting the DTC

P2177 or P2179

The Long Term Fuel Trim Cruise/Accel is greater than 32 % for 4 s or for a cumulative time of 30 s.