Powertrain Controls - ECM/PCM

Diagnostic Chart:

Electrical Schematic:

CIRCUIT DESCRIPTION
The ECM monitors the crank angle and the camshaft position. The ECM applies 0.70 volts to both the crank angle and the Camshaft Position (CMP) sensors. This voltage is toggled high and low by the rotation of the signal rotor. It is by the toggled voltage input that the ECM can determine the crank angle and camshaft positions.

DTC 13 will set if the following condition is met:
^ No crank angle input detected at the ECM for 0.30 seconds or more with engine speed above 1,500 rpm.

DTC CHART TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.
1. This checks the crank angle input low circuitry and ECM for faults.
2. This checks the crank angle input high circuitry and ECM for faults and also for a misadjusted signal rotor air gap.

DIAGNOSTIC AIDS
^ Check distributor cap and rotor for cracks.
^ Check that signal rotor air gap is adjusted properly.
^ Check power supply to ECM for correct voltage.

INTERMITTENT MALFUNCTIONS
An intermittent may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation. Inspect hamess connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connections before component replacement.