BMW X5: Ignition Coil

NOTES ON CHECKING IGNITION SYSTEM

Troubleshooting -> Fault in fuel injection system

-> Spark plug faults

-> Ignition coil faults

-> Further fault patterns with evaluation

-> Additional fault notes for troubleshooting.

Oscillograms -> Normal oscillogram

-> Oscillograms of ignition coils from different manufacturers

Check -> Secondary signal for stationary ignition distribution

CHECKING ROD-TYPE IGNITION COILS (M54, M56, N40, N42, N43, N45, N46, N52, N62, N62TU, N73)

Special tools required:

• 12 1 301
• 12 7 050

Necessary preliminary tasks:

• Read out fault memory in DME (Digital Engine Electronics)
• N40: Remove sound absorption hood
• N42: Remove sound absorption hood
• N43: Remove sound absorption hood
• N45: Remove sound absorption hood
• N46: Remove sound absorption hood
• N52: Remove sound absorption hood
• N62/N62TU: Remove sound absorption hood
• N62/N62TU: Remove ignition coil cover

Open control unit box

• Remove M54/56 ignition coil cover

Unlock plug fastener (1) of ignition coil.

Fig. 2: Unlocking Plug Fastener Of Ignition Coil

Detach plug (1) in direction of arrow.

Pull out ignition coil (2) towards top.

NOTE: Procedure applies to all rod-type ignition coils.

Fig. 3: Pulling Out Ignition Coil

Install special tool 12 7 050.

Installation:

Special tool 12 7 050 is attached between spark plug and rod - type ignition coil.

Fig. 4: Identifying Special Tool

Secondary measurement:

Connect KV clip-on probe (1) of DIS Tester to special tool 12 7 050. See 12 7 050 ADAPTER LEAD Procedure on DIS Tester:

• Select < Measurement >.
• Select < Preset measurement >.
• Select < Secondary ignition signal >.
• Connect < TD cable to diagnostic head >.
• Select < static ignition distribution >.
• Select < Number of cylinders >.

Fig. 5: Identifying KV Clip-On Probe Of DIS Tester

For subsequent procedure, follow DIS instructions.

NOTE: Illustration shows: KV clip-on probe (1) US version

Primary measurement:

Connect 26-pin pin box with special tool 12 1 301 to connector (1) DME module 5.

Procedure on DIS Tester:

• Select < Measurement >.
• Select < Preset measurement >.
• Select < Ignition signal term.1 >.

For subsequent procedure, follow DIS instructions.

Fig. 6: Identifying Connector DME Module 5

NOTE: Pin assignment acc. to connection scheme.

Illustration N42.

IMPORTANT: Ignition signal is a multiple spark ignition.

Illustration of multiple spark ignition

1. Start of ignition peak.
2. Level of ignition voltage.
3. Level of sparking voltage.
4. Spark duration.
5. Sparking voltage curve.
6. Start of decay process.
7. Decay process.

Fig. 7: Identifying Multiple Spark Ignition Signal

M54 / M56 / N40 / N42 / N45 / N46 / N62 / N73:

The following ignition oscillogram applies to engines with multiple spark ignition from a production date of April 2001:

Depending on engine temperature (approx. -20 º to 100º) and engine speed (< 2000 RPM, some ignition voltage peaks (approx. 1-5 ignition peaks) can occur before the typical ignition voltage characteristic.

The additional ignition peaks play no role in diagnosis.

The last ignition peak (1) on the oscillogram is decisive.

Fig. 8: Ignition Peak Oscillogram Graph

NOTE: The display of the ignition voltage peak is approx. 20-25 % lower than the real value.

Differences of 3000 to 4000 volts are permitted.

REPLACING IGNITION COIL (N52, N52K, N51)

Necessary preliminary tasks:

• Read out fault memory of DME control unit.
• Check stored fault messages.
• Switch off ignition.
• Remove ignition coil cover.

Unlock plug retainer of ignition coil (1) and disconnect plug.

Pull ignition coil (1) up and out.

This procedure is applicable to all ignition coils.

Installation:

Check that rubber seal of ignition coil (1) is correctly seated.

Fig. 9: Locating Ignition Coil Covers Screws And Holder

Installation:

Push plug (1) with plug retainer (2) open onto ignition coil.

Carefully close plug retainer (2) in direction of arrow.

Fig. 10: Unlocking Plug Fastener Of Ignition Coil

Installation:

The plug retainer must snap into place without great effort.

Fig. 11: Pulling Out Ignition Coil

Fig. 12: Identifying Rubber Seal On Ignition Coils Between Guides

Assemble engine.

NOTE: Now clear the fault memory.

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