2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1243

2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1243

DTC P0303

- Cylinder 3 Misfire Detected

DTC P0304

- Cylinder 4 Misfire Detected

DTC P0305

- Cylinder 5 Misfire Detected

DTC P0306

- Cylinder 6 Misfire Detected

Circuit/System Description

The engine control module (ECM) uses information from the crankshaft position sensor and the camshaft position sensors in order to determine

when an engine misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the ECM is able to detect

individual misfire events. A misfire rate that is high enough can cause 3-way catalytic converter damage. The malfunction indicator lamp (MIL)

will flash ON and OFF when the conditions for catalytic converter damage are present. DTCs P0301 through P0306 correspond to cylinders 1

through 6. If the ECM is able to determine that a specific cylinder is misfiring, the DTC for that cylinder will set.

Conditions for Running the DTC

* DTC P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, or P0338 is not set.

* The engine speed is between 450-6,500 RPM.

* The evaporative emissions (EVAP) leak detection is not active.

* The delivered torque signal is greater than 6 % at idle.

* The delivered torque signal is between 6-21 % with the transmission in drive.

* DTCs P0300 through P0306 run continuously when the above conditions exist for at least 1,000 engine revolutions.

Conditions for Setting the DTC

P0300

The ECM detects a crankshaft rotation speed variation indicating a misfire rate sufficient to cause emissions levels to exceed a predetermined value.

P0301, P0302, P0303, P0304, P0305, P0306

The ECM detects a crankshaft rotation speed variation indicating a single cylinder misfire rate sufficient to cause emissions levels to exceed

mandated standards.

Action Taken When the DTC Sets

* DTCs P0300-P0306 are Type B DTCs.

* When the MIL is flashing, the injector may be disabled for the misfiring cylinder to protect the catalytic converter.

* Depending on the conditions that set the code, the engine may go into Open Loop.

Conditions for Clearing the DTC

* DTCs P0300-P0306 are Type B DTCs.

* The DTC must pass under the same conditions that were present when the DTC failed.

Diagnostic Aids

* A misfire DTC could be caused by an excessive vibration from sources other than the engine. Inspect for the following possible sources:

- A tire or wheel that is out of round or out of balance

- Variable thickness brake rotors

- An unbalanced drive shaft

- Certain rough road conditions

- Transmission operation

- A damaged accessory drive component or belt; remove the belt and safely operate the engine to evaluate

* High resistance in the circuits of the injectors could set a misfire DTC without setting an injector DTC. Test the injector circuits of the

affected cylinder(s) for a high resistance if you suspect a condition.

Reference Information

Schematic Reference

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