2010 Cadillac CTS Sedan AWD V6-3.0L Page 1906
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
P2178 or P2180
* Before the ECM can report DTC P2178 or P2180, 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.
* DTCs P2178 and P2180 run continuously when the above conditions are met for approximately 300 s, after Closed Loop fuel control is
enabled.
P2188 or P2190
* Before the ECM can report DTC P2188 or P2190, 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.
* DTCs P2188 and P2190 run continuously when the above conditions are met for approximately 300 s, after Closed Loop fuel control is
enabled.
Conditions for Setting the DTC
P2178 or P2180
The Long Term Fuel Trim Cruise/Accel is less than -22 % for 4 s or for a cumulative of 30 s.
P2188 or P2190
The Long Term Fuel Trim Idle/Decel is less than -6 % for 4 s or for a cumulative of 30 s.
Action Taken When the DTC Sets
DTCs P2178, P2180, P2188, and P2190 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P2178, P2180, P2188, and P2190 are Type B DTCs.
Diagnostic Aids
* An HO2S will not cause this DTC to set without the occurrence of circuit related HO2S DTCs. Do not replace an HO2S to address this DTC.
* Observing the LT FT Bn 1 and Bn 2 parameters, while driving the vehicle can determine whether the rich condition is effecting only one
bank , or is common to both banks of the engine.
* A fuel system delivery condition causes this DTC to set. Thoroughly inspect all items that cause a rich condition. Refer to Fuel System
Diagnosis (See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests and General
Diagnostics/Fuel System Diagnosis).
* Review the Freeze Frame/Failure Records with a scan tool.
