Upgraded Emissions

CODE 41 IGNITION CONTROL CIRCUIT

Diagnostic Chart: Part 1 Of 2:

Diagnostic Chart: Part 2 Of 2:

Ignition Wiring Schematic:

CIRCUIT DESCRIPTION
The Engine Control Module (ECM) receives an ignition fail safe signal when the ignition switch is turned to the "Start" position. When the ECM receives this signal, it will toggle the igniter On and Off. As the igniter is toggled On and Off, so is the primary windings of the ignition coil, thus inducing a voltage into the secondary windings of the ignition coil. This induced voltage is then used to fire the spark plugs.

Diagnostic Trouble Code (DTC) 41 will set if the following condition is met: Toggled ignition fail safe signal not present at the ECM within 3 seconds of cranking.

TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.
(Part 1 Of 2)
1. This checks for power to the ignition coil.
2. This checks for a open or short to ground in BRN/WHT wire or for a faulty ignition coil.
3. This checks for a faulty ignition coil.
4. This checks for a faulty noise suppressor filter.
5. This checks for an open or short to ground in BRN/WHT or BRN wire.
(Part 2 Of 2)
6. This checks for an open in BLK wire.
7. This checks for a faulty BRN/YEL wire, igniter or ECM.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection rubbed through wire insulation or a wire broken inside the insulation. Inspect ECM harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.