Vehicle applicability: This diagnostic supplement covers multiple Ford vehicles and engines. Follow the application named in the source below. Some references apply to vehicles other than Mustang.
Clear the PCM DTCs. REPEAT the self-test.
JC10 CHECK FOR SPARK AT ALL CYLINDERS
• Ignition OFF.
• Disconnect the spark plug wires from the spark plugs.
• Connect the Adjustable Ignition Spark Tester THX458 or equivalent to a spark plug wire.
• Check for spark while cranking the engine.
Is the bluish-white spark present?
Yes | No |
|---|---|
GO to JC12 . | INSPECT the spark plug wires for missing cylinders. MEASURE the resistance of the spark plug wires. INSTALL a new spark plug wires, if the resistance is greater than 7,000 ohms per 30.5 cm (1 foot). REFER to the Workshop Manual Section 303-07, Engine Ignition. If the spark plug wires are OK, GO to JC11 . |
JC11 CHECK THE SECONDARY COIL RESISTANCE FOR THE MISSING CYLINDERS
Note: Two adjacent coil towers share a common coil and are called a matched pair. The matched pairs are 1 and 4, and 2 and 3.
• Ignition OFF.
• Ignition coil pack disconnected.
• Disconnect spark plug wires from the coil pack.
• Measure the resistance of each matched pair.
Is the resistance between 8,000 and 9,600 ohms?
Yes | No |
|---|---|
GO to Pinpoint Test Z . | INSTALL a new ignition coil pack. REFER to the Workshop Manual Section 303-07, Engine Ignition. Clear the PCM DTCs. REPEAT the self-test. |
JC12 CHECK THE SPARK PLUGS
• Ignition OFF.
• Check for damaged spark plugs or narrow spark plug gaps.
Are the plugs OK?
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.