2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1342
Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))
* Secondary Air Injection Pump Replacement (See: Powertrain Management/Emission Control Systems/Air Injection/Air Injection
Pump/Service and Repair)
P0418
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.
Conditions for Running the DTC
* The engine speed is greater than 80 RPM.
* The ignition voltage is between 10-18 V.
* The ECM has commanded the air pump relay ON and OFF at least once during the ignition cycle.
* The DTCs run continuously when the above conditions are met.
Conditions for Setting the DTC
P0418
The ECM detects the secondary air injection pump relay control circuit is open.
P2257
The ECM detects the secondary air injection pump relay control circuit is shorted to ground.
P2258
The ECM detects the secondary air injection pump relay control circuit is shorted to voltage.
Action Taken When the DTC Sets
DTC P0418, P2257, and P2258 are Type B DTCs.
