2010 Cadillac CTS Sedan AWD V6-3.6L Page 1939

2010 Cadillac CTS Sedan AWD V6-3.6L Page 1939

* 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 P2227

- Barometric Pressure (BARO) Sensor Performance

DTC P2228

- Barometric Pressure (BARO) Sensor Circuit Low Voltage

DTC P2229

- Barometric Pressure (BARO) Sensor Circuit High Voltage

Circuit/System Description

The barometric pressure (BARO) sensor responds to changes in altitude and atmospheric conditions. This gives the engine control module (ECM)

an indication of barometric pressure. The ECM uses this information to calculate fuel delivery. The BARO sensor is located within the controller

and is not serviced as a separate unit. The BARO sensor provides a voltage signal to the ECM relative to the atmospheric pressure changes. The

ECM monitors the BARO sensor signal for a voltage outside of the normal range.

Conditions for Running the DTC

P2227

* Before the ECM can report DTC P2227 failed, DTCs P0100, P0101, P0102, P0103, P0121, P0122, P0123, P0221, P0222, P0223, P2228,

and P2229 must run and pass.

* The engine is operating for greater than 1 s.

* The mass air flow sensor signal is valid.

* The evaporative emission (EVAP) leak test is not enabled.

* DTC P2227 runs continuously once the above conditions are met for 2 s.

P2228 or P2229

* The engine is operating.

* The DTCs run continuously once the above conditions are met for 2 s.

Conditions for Setting the DTC

P2227

* The ECM detects that the BARO pressure is less than 50 kPa or greater than 115 kPa and DTC P2228 or P2229 is not set.

* The ECM detects that the BARO pressure changed greater than 10 kPa within 20 s.

* The ECM detects that the BARO pressure changed greater than 30 kPa since the last ignition cycle, and the difference between the BARO

signal and the calculated BARO is greater than 2 kPa. The condition exists within 1 s of engine start up.

* DTC P2227 sets if any of the conditions above exist for greater than 1 s.

P2228

The ECM detects that the BARO sensor voltage is less than 0.20 V for 1 s.

P2229

The ECM detects that the BARO sensor voltage is greater than 4.87 V for 1 s.

Action Taken When the DTC Sets

DTCs P2227, P2228, and P2229 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P2227, P2228, and P2229 are Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics (LLT) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics

(LF1) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)