Powertrain Controls - ECM/PCM

No RPM Signal:

Ignition Circuit:

Circuit Description:
The engine control module (ECM) monitors the crank angle and the camshaft position. The ECM applies 0.70 volts to 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.




Test Description:
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. Also check that signal rotor air gap is adjusted properly.

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.