GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2003 🢒 CTS - RHD 🢒 Engine 🢒 Engine Electrical 🢒 Hard Start

Inspections

Action

DEFINITION: Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.

Preliminary
    • Refer to Important Preliminary Inspections Before Starting in Symptoms - Engine Controls .
    • Inspect the engine control module (ECM) grounds for being clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics .
    • Search for service bulletins that may address this condition.

Sensor/System
    • Confirm the correct operation of the theft deterrent system. Refer to Diagnostic System Check - Theft Deterrent in Theft Deterrent.

       Important: Allow the engine to cool before performing this test.

    • Inspect the engine coolant temperature (ECT) sensor for being skewed in value. Connect a scan tool. Compare the ECT against the intake air temperature (IAT) on a cold engine. The ECT and IAT sensor values should be within ± 3°C (5°F) of each other. If the ECT sensor is out of range with the IAT sensor, test the resistance of the ECT sensor. Refer to Temperature Versus Resistance - Engine Coolant Temperature Sensor for resistance specifications. Replace the ECT sensor if the resistance is not within the specification. Refer to Engine Coolant Temperature Sensor Replacement . If the sensor is within the specification, repair the high resistance in the ECT signal circuit.
    • Inspect the MAF sensor installation. A MAF sensor that is incorrectly installed may cause a hard start. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement .
    • Verify proper operation of the throttle actuator control (TAC) system by performing the following procedure:
       - Observe the TP sensor angle with a scan tool
       - Turn the key ON, with the engine OFF.
       - Slowly depress the accelerator pedal to wide open throttle (WOT), then slowly return the pedal to the rest position. Repeat several times.
       - TP sensor angle should increase to near 100 percent as the pedal is depressed, and decrease as the pedal is released. A verification of the entire TAC system will be performed.

Fuel System
    • Test the fuel pump relay operation. Refer to Fuel Pump Electrical Circuit Diagnosis .
    • Test for any of the following fuel pressure related conditions. Refer to Fuel System Diagnosis .
       - An inoperative check valve in the fuel pump allowing the fuel in the lines to drain back to the tank after the engine stops
       - Incorrect fuel pressure
       - Restricted fuel filter
    • Test for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Test for plugged or restricted injectors. Refer to Fuel Injector Balance Test with Special Tool .

Ignition System
    • Test for proper ignition system operation. Refer to Electronic Ignition (EI) System Diagnosis .
    • Remove the spark plugs and inspect for the following conditions. Refer to Spark Plug Replacement .
       - Correct heat range
       - Wet plugs
       - Cracks
       - Wear
       - Improper gap
       - Burned electrodes
       - Heavy deposits
    • Determine the cause of the fouling before replacing the spark plugs if the spark plugs are gas, coolant or oil fouled. Refer to Spark Plug Inspection . Once you determine the cause of the fouling, refer to one of the following procedures:
       - For diagnosis of a rich condition, refer to DTC P0172 or P0175 .
       - For diagnosis of coolant contaminated spark plugs, refer to Loss of Coolant in Engine Cooling.
       - For diagnosis of oil fouled spark plugs, refer to Oil Consumption Diagnosis in Engine Mechanical.

Engine Mechanical
    • Low cylinder compression--Refer to Engine Compression Test in Engine Mechanical.
    • Combustion chambers for excessive carbon buildup--Clean the chambers using top engine cleaner. Follow the instructions on the can.
    • Inspect for incorrect camshaft timing--Refer to Timing Belt Timing Adjustment in Engine Mechanical.
    • Excessive oil in combustion chamber due to leaking valve seals--Refer to Oil Consumption Diagnosis in Engine Mechanical.
    • Inspect the following components for incorrect basic engine parts:
       - The cylinder heads--Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical.
       - The camshafts--Refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical.
       - The pistons, connecting rod, and/or bearings--Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection in Engine Mechanical.