Electronic Ignition (EI) System Diagnosis. Oldsmobile Aurora 2001

For 1990-2009 cars only

Makes 🢒 Oldsmobile 🢒 2001 🢒 Aurora 🢒 Engine 🢒 Engine Controls - 3.5L 🢒 Electronic Ignition (EI) System Diagnosis

Circuit Description

There are two separate ignition module assemblies, one for each bank of cylinders. Each assembly contains an ignition control (IC) module and three ignition coils. Each IC module consists of the following circuits:

•	Ignition 1 voltage

•

Ground

•	IC timing low reference

•	IC control circuits for cylinders 1-6

Each ignition coil connects directly to its spark plug via a short boot. The IC circuits transmit timing pulses from the powertrain control module (PCM) to the IC modules, which triggers the coils to fire the plugs in the correct sequence. The PCM monitors each IC circuit for improper voltage levels.

Diagnostic Aids

When servicing the ignition system components, use the following recommended procedures:

•	If a boot remains attached to a coil or a spark plug, twist the boot prior to removal. Use the J 43094 Spark Plug Boot Removal Tool.

•	Check the boot for a missing or damaged internal spring.

•	Do not re-install any component that has visible signs of damage.

•	Install the boots onto the coils until bottomed out. Then install the assembly onto the spark plugs. If this is not possible due to space limitations, just-start the boots onto the spark plugs and then install the coil assembly as straight down onto the plugs as possible.

•	Ensure the boots are installed right side up.

•	Lift the module beauty cover at the end opposite the module to remove the cover.

•	Repair a torn perimeter seal with an RTV sealant.

•	Adhere to the torque specifications when installing the cassette to the cam cover and the module to the cassette. Refer to Fastener Tightening Specifications and Ignition Coil Replacement .

Test Description

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

If any IC circuit diagnostic trouble codes (DTCs) are set, perform the DTC table first. If no IC circuit DTCs are set, check the IC Circuit Status for all cylinders. If an IC Circuit Status indicates anything other than OK, even momentarily, perform the corresponding IC circuit DTC table as if the DTC were set.

A misfiring or dead cylinder can sometimes affect the misfire counters for other cylinders. When performing this table, concentrating on the cylinder with the highest level of misfire and correcting the problem may also correct the other cylinders that indicate misfire. If multiple cylinders are suspected, perform each test on all affected cylinders. An ignition coil, the boots, or the spark plugs may fail only when moisture is present. Although difficult to test on this engine, selectively wetting down parts of the system and rechecking for a misfire or any arcing may uncover a problem with one or more components. If moisture is present in the spark plug and ignition coil cavity of the cam cover, check the perimeter seal for damage. Repair tears in the perimeter seal with an RTV sealant. Ensure that the 7 cassette mounting bolts are tightened to the specified torque.

The J 26792 spark tester (ST 125) presents a more difficult load on the secondary ignition than a normal spark plug. If a miss, a stumble, or a hesitation is being caused by a spark plug not firing, the spark tester should also not fire.

A suspected ignition system miss may actually be a fuel system problem. Perform the Cuts Out, Misses , if the diagnosis has not yet been performed. An internal engine problem can also cause a driveability concern.

If the misfire disappears when running the engine using the J 36012 spark plug jumper wires, and misfire is present when the boots are installed, replace the affected boot.

An ignition coil, the boots, or the spark plugs may fail only when moisture is present. Although difficult to test on this engine, selectively wetting down parts of the system and rechecking for a misfire or any arcing may uncover an intermittent problem. If moisture is present in the spark plug and/or ignition coil cavity of the cam cover, check the perimeter seal for damage. Repair tears in the perimeter seal with an RTV sealant. Ensure that the 7 cassette mounting bolts are tightened to the specified torque.

Ensure good DMM contact when measuring the spark plug resistance. When manufactured, the normal resistance for the spark plug is 3000-8000 ohms. A suspected ignition system miss may actually be a fuel system problem. Perform the Cuts Out, Misses. An internal engine problem can also cause a driveability concern.

If the spark plug exhibits unusual signs of damage or deposits, diagnose and correct the root cause of the problem, such as excessive detonation, the wrong spark plug or an incorrect heat range for the application, a base engine problem, etc.

Be sure to use the correct adaptor harness when connecting the ignition module tester to the LX5 engine. Using an adaptor harness for a different engine application will result in incorrect tool operation.

The green power light emitting diode (LED) should come on any time the ignition module tester is connected and the ignition switch is in the run position. This LED simply indicates that the J 43298 ignition module tester is receiving adequate power and ground to perform the test. The Test button is used as an LED check for the 4 red LEDs. To use this function, connect the tool, turn the ignition switch to run, then momentarily press the Test button. All 4 red LEDs should come on brightly. The crank the vehicle. If the 3 red LEDs flash, this confirms correct operation of the primary ignition system. The ignition module tester may get hot during actual testing as the tester is attempting to simulate the load of the ignition coils' primary windings.

Only 3 of the red LEDs are used when testing the LX5 engine. Four LEDs are provided on the tester for 8-cylinder applications.

If 3 LEDs flash, the module output drivers are operating. If one or more LEDs are inoperative, excluding the one unused LED, and no IC circuit DTCs are set, replace the module.

Electronic Ignition Diagnosis

Step

Action

Value(s)

Yes

Schematic Reference:

Igntion Control Modules

Master Electrical Component List
Electronic Ignition (EI) System Description
Camshaft and Crankshaft Position Sensors, TCC/Cruise Release Switch
Ignition Switch and Controls
OBD II Symbol Description Notice
Battery Feed to the Fuse Block-Underhood

Did you perform the Diagniostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

Start the engine.
Select the Misfire Current counters on the scan tool.

Do any cylinders indicate an excessive amount of misfire?

Go to Step 3

Go to Step 11

Is an entire bank of cylinders inoperative?

Go to Step 16

Go to Step 4

Use the scan tool in order to check for DTC P1351-P1366.
If no IC circuit DTCs are set, check the IC Circuit Statuses.

Are any IC circuit DTCs set, or does the IC Circuit Status for any cylinder indicate anything other than OK?

Go to Diagnostic Trouble Code (DTC) List DTC List

Go to Step 5

The remaining steps are to be performed on the cylinder indicating the highest level of misfire.

Disconnect the coil assembly from the spark plugs.
Inspect the coil assembly, the boots, and the spark plug insulators for the following conditions:

•	Any visible cracks, deterioration, or other damage

•	Any carbon tracking, or other signs of arcing

Did you find a problem?

Go to Step 20

Go to Step 6

Using the J 26792 spark plug jumper wires, connect the coils to the spark plugs.
Disconnect the spark plug on the affected cylinder and install the J 26792 spark tester .
Crank the engine and note the spark tester. If the engine starts, turn the engine OFF after checking the spark tester.

Does a spark jump the tester gap?

Go to Step 7

Go to Step 10

Remove the spark plug on the affected cylinder.

Does the spark plug show signs of oil or coolant entering the combustion chamber?

Go to Symptoms - Engine Mechanical in Engine Mechanical

Go to Step 8

Inspect the spark plug for the following conditions:

•	Any cracks

•	Any excessive wear

•	An improper gap

•	Any burned electrodes

•	Any heavy deposits

•	Any fuel fouling

Refer to Spark Plug Inspection .

Did you find a problem?

Go to Step 24

Go to Step 9

Install this spark plug in a different cylinder--switch the two spark plugs.
Reconnect the coils to the plugs using the spark plug jumper wires.
Select the Misfire Current counters on the scan tool.
Start the engine.

Did the misfire follow the spark plug?

Go to Step 24

Go to Diagnostic Starting Point - Engine Mechanical in Engine Mechanical

Important: Remove the fuel pump fuse before proceeding. Running or cranking the engine with an ignition control module disconnected will cause excessive engine fueling if the fuel pump is not disabled.

Turn OFF ignition.
Remove the fuel pump fuse.
Disconnect the harness connector from the ignition control (IC) module .
Connect a DMM between the ignition control circuit for the affected cylinder and ground.
Set the DMM to AC Hertz.
Measure the frequency on the ignition control circuit for the affected cylinder while cranking the engine.

Does the frequency measure within the specified range?

2-20 Hz

Go to Step 25

Go to Step 30

Select the Misfire History counters using the scan tool.

Do any cylinders indicate a history of misfiring?

Go to Step 12

Go to Step 33

The remaining steps are to be performed on the cylinder indicating the highest level of misfire.

Disconnect the coil assembly from the spark plugs.
Inspect the coil assembly, the boots, and the spark plug insulators for the following conditions:

•	Any visible cracks, deterioration, or other damage

•	Any carbon tracking or other signs of arcing

Did you find a problem?

Go to Step 20

Go to Step 13

Does the spark plug show signs of oil or coolant entering the combustion chamber?

Go to Diagnostic Starting Point - Engine Mechanical in Engine Mechanical

Go to Step 14

Remove the spark plug on the affected cylinder.
Check the spark plug for the following conditions:

•	Any cracks

•	Any excessive wear

•	An improper gap

•	Any burned electrodes

•	Any heavy deposits

•	Any fuel fouling

Did you find a problem?

Go to Step 24

Go to Step 15

Measure the resistance of the affected spark plugs.

Does the resistance measure less than the specified value?

15K ohms

Go to Diagnostic Starting Point - Engine Mechanical in Engine Mechanical

Go to Step 24

Turn OFF the ignition.
Disconnect the ignition control module for the affected cylinders.
Turn ON the ignition.
Using a test lamp connected to ground, probe the ignition feed circuit in the ignition control module harness.

Does the test lamp illuminate?

Go to Step 17

Go to Step 21

Connect a test lamp between the ignition feed circuit and the ground circuit in the ignition control module harness.

Does the test lamp illuminate?

Go to Step 18

Go to Step 22

Using the DMM, measure the resistance between the ground circuit and the reference low circuit in the harness connector of the ignition control module .

Does the resistance meaure less than or equal to the specified value?

5 ohms

Go to Step 19

Go to Step 23

Turn OFF the ignition.

Remove the fuel pump fuse.
Disconnect the harness connector for the ignition control module.
Connect the DMM between the IC circuit of one of the affected cylinders and ground.
Set the DMM to AC Hertz.
Measure the frequency while cranking the engine.
Repeat the test on each IC circuit.

Does the frequency measure within the specified range for all circuits tested?

2-20 Hz

Go to Step 25

Go to Step 30

Perform any repairs as necessary.

Did you complete the repairs?

Go to Step 31

Go to Step 33

Repair the open or high resistance in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

Go to Step 33

Repair the open or high resistance in the ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

Go to Step 33

Repair the open or high resistance in the low reference circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

Go to Step 33

Replace the spark plugs as necessary. Refer to Spark Plug Replacement .

Did you complete the replacement?

Go to Step 31

Go to Step 33

Turn OFF the ignition.

Remove the ignition control module from the ignition coil assembly. If the mating connector between the module and the coils came off with the module, remove the mating connector and install the connector into the coil assembly.
Reconnect the ignition control module to the engine harness.
Connect the J 43298 ignition module tester to the ignition control module.
Crank the engine while observing the tester.

Do 3 LEDs flash ON and OFF as the engine is cranked?

Go to Step 26

Go to Step 28

Check for poor connections or terminal tension between the IC module and the coil assembly. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems .

Did you find and correct the condition?

Go to Step 31

Go to Step 27

Replace the affected coil assembly. Refer to Ignition Coil Replacement .

Did you complete the replacement?

Go to Step 31

Go to Step 33

Check for poor connections or terminal tension at the IC module. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems .

Was a problem found and corrected?

Go to Step 31

Go to Step 29

Replace the ignition control module. Refer to Ignition Control Module Replacement .

Did you complete the replacement?

Go to Step 31

Go to Step 33

Important: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 31

Go to Step 33