Circuit/System Verification
WARNING: This page is about a different car, the 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
This diagnostic assumes the following:
- The battery is completely charged. Refer to Battery Inspection/Test .
- The engine cranking speed is acceptable. Refer to Engine Cranks Slowly .
- There is adequate fuel in the fuel tank.
- Crank the engine for 15 seconds. Observe the DTC information with a scan tool. The following DTCs should not be set:
DTC P0201-P0204, P0335, P0336, P0601, P0602, P0603, P0604, P0605, P0606, P060E, P0627, P0685, P0686, P0687, P0689, P0690
- If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Ignition ON, observe the Theft Deterrent parameter with a scan tool. The parameter should display Disabled.
- If Enabled is displayed, refer to Symptoms - Theft Deterrent .
- Ignition ON, command the fuel pump ON with a scan tool. You should hear the fuel pump turn ON.
- If the fuel pump does not turn ON, refer to Fuel Pump Electrical Circuit Diagnosis .
- Ignition OFF, disconnect the fuel pump relay.
- Disconnect an ignition coil from a cylinder.
- Connect a J 26792 to the boot of an ignition coil of a cylinder and ground. See Special Tools .
- While cranking the engine, verify that the spark tester sparks.
- If there is no spark, refer to Electronic Ignition (EI) System Diagnosis .
- Ignition OFF, install the fuel pump relay.
- Install the CH-48027 . See Special Tools . Refer to Fuel Pressure Gage Installation and Removal .
- The fuel pump may need to be commanded ON a few times, in order to obtain the highest possible fuel pressure.
- Do NOT start the engine for this test.
- Ignition ON, command the fuel pump ON with a scan tool. The fuel pressure should be between 345-414 kPa (50-60 psi).
- If the fuel pressure is not within the specified range, refer to Fuel System Diagnosis .
- Verify that the following conditions do not exist:
- Collapsed air intake duct to the throttle body
- Restricted air filter element
- Spark plugs for being gas or coolant fouled-Refer to Spark Plug Inspection
- A skewed manifold absolute pressure (MAP) sensor-Compare the MAP Sensor parameter to the Altitude Versus Barometric Pressure table. Refer to Altitude Versus Barometric Pressure .
- A skewed engine coolant temperature (ECT) sensor-Compare the ECT Sensor parameter to the Temperature Versus Resistance table. Refer to Temperature Versus Resistance (ECT) or Temperature Versus Resistance (IAT 1) or Temperature Versus Resistance (IAT 2) .
- Exhaust system restricted-Refer to Restricted Exhaust .
- Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- Engine mechanical condition, for example, worn timing belt or low compression-Refer to Symptoms - Engine Mechanical .
- If you find any of the above conditions, repair as necessary.
IMPORTANT:
An erratic or weak spark is considered a no spark condition.
IMPORTANT: