GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Eldorado 🢒 Body and Accessories 🢒 Data Link Communications 🢒 Engine Cranks But Does Not Run

Circuit Description

To start the engine, the correct air/fuel mixture must be compressed within the cylinder, and sparked at the proper time. This assumes that the vehicle battery condition and cranking speed is within specifications, and that an adequate amount of quality fuel is in the tank. The PCM controls fuel delivery, fuel metering, and spark timing. When the key is first turned ON, the PCM energizes the fuel pump to prime the fuel rail assembly. The PCM uses input from various information sensor s to determine the correct amount of fuel to mix with the intake air, and the spark timing of the mixture over a wide range of starting conditions.

Diagnostic Aids

To prevent mis-diagnosis, perform the Powertrain On Board Diagnostic (OBD) System Check before performing this table.

Unless the engine enters Clear Flood at the first indication of a flooding condition, a no start may result. Be sure to check the spark plugs for signs of fouling.

Check for leaks in the air duct between the mass air flow (MAF) sensor and the throttle body.

If the steps above check OK, refer to Hard Start in Symptoms.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step determines if the ignition feed circuit to the CKP and the CMP is shorted to a ground. If all three DTCs are set, this indicates the circuit is shorted to a ground or a sensor is internally shorted.

    2.

  2. If the fuel pump is not audible at the fuel tank area, listen underhood at the fuel rail. Fuel flowing through the pressure regulator produces an audible hiss.

    3.

  3. This step determines if the ignition control modules are powered up. If the test lamp does not illuminate. this indicates the voltage supply circuit is open before it splits to both banks of the engine or the circuit is grounded and the ignition control module fuse is open.

Step

Action

Value(s)

Yes

No

1

Did you perform A On Board Diagnostic System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Turn ON the ignition, with the engine OFF.
  2. With a scan tool, observe the DTC information.

Does the scan tool display DTC P0335, P0340, and P0385?

--

Go to DTC P0335 CKP Sensor A Circuit Performance

Go to Step 3

3

Does the scan tool display DTC P0230, P0601, P0602, P0603, P0604, P0606, P1621, P1630 or P1631 set?

--

Go to Diagnostic Trouble Code (DTC) List/Type

Go to Step 4

4

With a scan tool, command the fuel pump ON.

Does the fuel pump turn ON?

--

Go to Step 5

Go to Fuel Pump Circuit Diagnosis

5
  1. Turn OFF the ignition.
  2. Install the J 34730-1A . Refer to Fuel System Pressure Test .
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the fuel pump ON.

Is the fuel pressure within the specified range while the fuel pump is operating?

284-325 kPa

(41-47 psi)

Go to Step 6

Go to Fuel System Pressure Test

6

  1. Turn OFF the ignition.
  2. Disconnect an ignition control module harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the supply voltage circuit of the ignition control module with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 7

Go to Secondary Ignition Diagnosis

7

Connect a test lamp between the supply voltage circuit of the ignition control module and the ground circuit of the ignition control module.

Does the test lamp illuminate?

--

Go to Step 8

Go to Secondary Ignition Diagnosis

8

Inspect for the following conditions:

    • Collapsed air intake duct
    • Restricted air filter element. Refer to Air Cleaner Element .
    • Spark plugs for being gas, coolant, or oil fouled. Refer to Spark Plug Visual Diagnosis in Engine Electrical. If the spark plugs are fouled, determine what caused the condition.
    • Engine mechanical condition (worn timing chain and gears, low compression, etc.). Refer to Engine Compression Test in Engine Mechanical.
    • Restricted exhaust system. Refer to Restricted Exhaust System Check .
    • The engine coolant temperature (ECT) sensor is NOT close to the actual engine temperature. Refer to DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage or DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage .
    • Compare MAP/BARO parameters to another vehicle. The parameters should be close in value. Refer to DTC P0106 Manifold Absolute Pressure (MAP) System Performance .
    • TP sensor for being stuck in range. Refer to DTC P0121 TP Sensor Circuit Insufficient Activity .

Did you find and correct the condition?

--

Go to Step 9

Go to Diagnostic Aids

9
  1. With a scan tool, clear the DTCs.
  2. Attempt to start the engine.

Does the engine start and continue to operate?

--

Go to Step 10

Go to Step 2

10
  1. Idle the engine.
  2. Allow the engine to reach operating temperature.
  3. With a scan tool, observe the DTC information.

Are any DTCs displayed?

--

Go to Diagnostic Trouble Code (DTC) List/Type

Go to Step 11

11

With a scan tool review the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List/Type

System OK