Electronic Ignition (EI) System Diagnosis. Buick GL7 (Export) 2000

For 1990-2009 cars

Refer to Engine Controls Schematics .

### Circuit Description

The vehicle theft deterrent (VTD) module produces the theft deterrent fuel enable signal when ignition is ON and the proper key resistor pellet is detected. The powertrain control module (PCM) monitors the fuel enable signal during crank. If the proper signal is present on the Class II Serial Data Circuit, the PCM enables the fuel delivery in order to allow the engine to start. If the PCM determines that the fuel enable signal is not present or incorrect while the engine is running, DTC P1626 is set. The engine continues to start and run as long as DTC P1626 is stored. If the problem affects inputs to the VTD signal, the starter motor may be disabled. Refer to and .

### Test Description

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

1. It is necessary to disconnect the 24X crankshaft sensor to ensure that the 7X signal is being read in the 3X reference parameter on the scan tool.

1. The J 26792 spark tester presents a more difficult load on the secondary ignition than a normal spark plug. If a miss, stumble, or hesitation is being caused by a spark plug not firing, the spark tester should also not fire.

2. Use a 5 percent saltwater solution in a spray bottle to induce voltage arcing to ground through faulty insulation of the spark plug wires.

3. If the no-spark condition follows the suspected coil, the coil is faulty. Otherwise, the ignition module is the cause of the no-spark. This test could also be performed by substituting a known good coil for the coil causing the no-spark condition.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | Go to step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check

2

1. Disconnect the 24X Crank Sensor.
2. With a scan tool, observe the 3X reference parameter while cranking the engine.

Does the scan tool indicate 3X reference signal present?

--

Go to step 3

Go to step 10

3

1. Reconnect the 24X Crank Sensor.
2. With a J 26792 Spark Tester, test for spark at each cylinder.

Did you observe any non-sparking cylinders?

--

Go to step 4

Go to step 7

4

Inspect and test the affected cylinder spark plug wire(s), Ignition coil(s), and Spark plugs for a short to ground or arching to ground. If Carbon tracking or corrosion is present, replace both components affected. Refer to Spark Plug Wire Harness Replacement in Engine Electrical, and Ignition Coil Replacement .

Did you find and correct the condition?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

Go to step 5

5 | Test affected spark plug wire(s) for proper resistance. Replace spark plug wire(s) not near specification. Refer to Spark Plug Wire Harness Replacement in Engine Electrical. Did you find and correct the condition? | 600ohms per ft (1,968ohms per M) | Go to Powertrain On Board Diagnostic (OBD) System Check | Go to step 6
6 | Switch the affected cylinder coil with a known good one. If the fault follows the affected coil replace it. Refer to Ignition Coil(s) Replacement, in Engine Controls. Did you find and correct the condition? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check | Go to step 14
7 | Inspect the spark plug wires for proper routing and for the correct firing order. If any spark plug wires are found to be misrouted, reroute as necessary. Refer to Spark Plug Wire Harness Replacement in Engine Electrical. Did you find and correct the condition? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check | Go to step 8
8 | With a DMM, test spark plugs for internal short to ground. Replace any grounded Spark plugs found. Refer to Spark Plug Replacement in Engine Electrical. Did you find and correct the condition? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check | Go to step 9

9

1. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Electrical.
2. Inspect spark plugs for damage. Refer to Spark Plug Visual Diagnosis in Engine Electrical.

If any spark plugs are found to be bad, replace the affected spark plugs. Refer to Spark Plug Replacement in Engine Electrical.

Did you complete the replacement?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

--

10

1. Reconnect the 24X Crank Sensor.
2. Disconnect the IC Module connector C2.
3. Turn ON the ignition.
4. With a test lamp connected to a good ground, probe the IC Module ignition feed circuit.

Does the test lamp illuminate?

--

Go to step 11

Go to step 16

11 | Connect a test lamp between the IC Module ignition feed circuit and IC Module ground circuit. Does the test lamp illuminate? | -- | Go to step 12 | Go to step 19

12

1. Disconnect the 7X Connector C2 from the IC Module.
2. With a test lamp connected to battery positive voltage probe both the 7X Reference High and 7X Reference Low circuits.

Does the test lamp illuminate when probing either circuits?

--

Go to step 17

Go to step 13

13

1. Connect a test lamp to ground.
2. Probe both the 7X Reference High and 7X Reference Low circuits.

Does the test lamp illuminate when probing either circuits?

--

Go to step 18

Go to step 14

14

1. Ensure the Battery voltage is within specifications.
2. Turn OFF the ignition.
3. Connect a DMM between the 7X reference high circuit and the 7X reference low circuit at the IC Module harness connector.
4. Crank the engine while observing AC Duty Cycle (%) .

Does the DMM indicate AC Duty Cycle present?

--

Go to step 20

Go to step 15

15

Test the 7X Crank Sensor circuits for the following conditions:

• | Opens

• | 7X Reference high and 7X reference low circuits shorted together.

Repair any damaged wiring. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

Go to step 21

16

1. Repair the open or short to ground in the IC Module Ignition feed circuit. Refer to Wiring Repairs in Wiring Systems.
2. Replace the fuse if necessary.

Did you complete the repair?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

--

17 | Repair the short to ground in the 7X Reference circuit which illuminated the test lamp. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check | --
18 | Repair the short to voltage in the 7X Reference circuit which illuminated the test lamp. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check | --
19 | Repair the open in the IC Module ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check | --
20 | Replace the IC Module. Refer to Ignition Coil Replacement . Did you complete the replacement? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check | --
21 | Replace the 7X Crank Sensor. Refer to Crankshaft Position Sensor Replacement . Did you complete the replacement? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check | --