2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1342

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.