Powertrain Controls - ECM/PCM

DTC 41:

Ignition Coil Circuit:

CIRCUIT DESCRIPTION:
The Electronic Control Module (ECM) receives an ignition signal when the ignition switch is turned to the "ON" position. When the ignition switch is turned to the start position, this signal is toggled "ON" and "OFF" through the ECM. As this signal is toggled "ON" and "OFF," so is the coil, thus inducing a voltage in the secondary coil of the ignition coil. This induced voltage is than used to fire the spark plugs. DTC 41 will set if the following condition is met: Toggled ignition signal not present at the ECM within 3 seconds of cranking.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. This checks for power to the ignition coil.

2. This checks for a poor connection or for a faulty ignition coil

3. This checks for a poor connection or for a faulty ECM.

4. This checks for a faulty noise suppressor filter.

5. This checks for an open or short to ground in wires between ignition coil, noise suppressor filter and 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.