2010 Cadillac CTS Sedan AWD V6-3.6L Page 1285
Component Testing
1. Remove the intake manifold and disconnect the appropriate fuel injector.
2. Verify the resistance of each fuel injector with one of the following methods:
* If the engine coolant temperature (ECT) sensor is between 10-32掳C (50-90掳F), the resistance of each fuel injector should be 1.25-1.75
ohm.
瀚慖f not within the specified range, replace the fuel injector.
* If the ECT sensor is not between 10-32掳C (50-90掳F), measure and record the resistance of each fuel injector with a DMM. Subtract the
lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal
to or less than 0.45 ohm.
瀚慖f the difference is more than 0.45 ohm, add all of the fuel injector resistance values to obtain a total resistance value. Divide the total
resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest individual fuel injector
resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance
value and the average resistance value. Replace the fuel injector that displays the greatest difference above or below the average.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Fuel Injector Replacement (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Injector/Service and Repair/Fuel Injector
Replacement)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
P0300
DTC P0300-P0306 (w/LLT)
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 P0300
- Engine Misfire Detected
DTC P0301
- Cylinder 1 Misfire Detected
DTC P0302
- Cylinder 2 Misfire Detected
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
