Diagnostic Procedure

Check connectors for signs of corrosion, poor connection and damage. See CHECKING WIRING & CONNECTIONS . Repair as necessary and go to next step.
If wiring is OK and fault remains, connect breakout box. See CONNECTING & DISCONNECTING BREAKOUT BOX .
NOTE: An electrician's screwdriver with at least a 3-Watt (minimum) bulb will help diagnosis short to voltage.

Check for an open circuit, short to supply voltage and a short to ground between ignition coil terminal No. 1 and corresponding PCM terminal. See Figure. See IDENTIFYING PCM TERMINALS FOR IGNITION COIL TERMINAL NO. 1 table. Repair as necessary and go to next step.

NOTE: Normal voltage signal for ignition coils with engine idling is approximately 2.5 volts.

IDENTIFYING PCM TERMINALS FOR IGNITION COIL TERMINAL NO. 1

DTC	PCM Terminal
ECM 3300	A31
ECM 3310	A30
ECM 3320	A50
ECM 3330	A52
ECM 3400	A51

Check for short circuit to power supply between system relay terminal No. 3 and ignition coil terminal No. 4. See Figure. Repair as necessary and go to next step. If no faulty wiring is found and voltage at ignition coil is not within specification, replace ignition coil. See REMOVAL, OVERHAUL & INSTALLATION - EXCEPT S40 & V40 article.
NOTE: For system relay location, see COMPONENT LOCATIONS .
After completing repair, check that fault has been repaired. Ignition OFF. Ensure connectors and components are installed correctly. Start engine. Engine should fire on all cylinders. If engine fires on all cylinders, turn ignition OFF and connect scan tool. Start engine again and read out fault status. If fault is no longer present, repair is complete.