Sunday, July 11, 2021

2010 Cadillac Truck SRX AWD V6-3.0L Page 2021

2010 Cadillac Truck SRX AWD V6-3.0L Page 2021



3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.



瀚慖f less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal,



replace the K20 ECM.



瀚慖f greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.



4. Verify the scan tool BARO parameter is less than 1 kPa (0.2 psi).



瀚慖f greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the K20 ECM.



5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 1. Verify the scan tool BARO



parameter is greater than 127 kPa (18.4 psi).



瀚慖f less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace



the K20 ECM.



6. If the circuits test normal, replace the B17 BARO sensor.



Repair Instructions



Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.



* Throttle Inlet Absolute Pressure Sensor Replacement (LF1) (See: Powertrain Management/Computers and Control Systems/Absolute



Pressure Sensor/Service and Repair) for BARO sensor replacement



* Control Module References (See: Testing and Inspection/Programming and Relearning) for engine control module replacement, setup, and



programming



P2257



DTC P0418, P2257, or P2258



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 Descriptors



DTC P0418



- Secondary Air Injection Pump Control Circuit



DTC P2257



- Secondary Air Injection Pump Relay Control Circuit Low Voltage



DTC P2258



- Secondary Air Injection Pump Relay Control Circuit High Voltage



Diagnostic Fault Information



Circuit/System Description



The secondary air injection system aids in the reduction of hydrocarbon emissions during a cold start. The electric air pump forces fresh air into the



exhaust stream in order to accelerate the catalyst operation. Ignition voltage is supplied directly to the secondary air injection pump relay. The



engine control module (ECM) controls the relay by grounding the control circuit with a solid state device called a driver. The driver is equipped



with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a



voltage by monitoring the feedback voltage.

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