Actron CP9087 Service Manual page 56

Section 2
Where is
It?
When to
Test
What to
Inspect
2-48
Testing Sensors
— Crankshaft Position, Crank Angle, Flywheel, Distributor
Pick-Up, Camshaft Position, Cylinder, TDC and RPM. The
sensor is usually located inside the distributor (if the
engine has one). Vehicles without a distributor have the
sensor located in various places around the engine where
it can be mechanically linked to the crankshaft or camshaft.
— Driveshaft: Sensor located in transmission housing or
near driveshaft.
— Wheel Speed, Vehicle Speed: Sensors on individual
wheels, drive shaft, or transmission shaft.
• Related trouble codes sent by computer.
• Problems with...
– Ignition: No start, stalling, rough running.
– Electronic Transmission: No torque converter lock-up,
faulty shifting or slipping.
– ABS system: Faulty or not working.
All Sensor Types: Sensor operation (see tests on page 2-
49 through 2-52). Poor connections at sensor or computer.
Faulty sensor wiring (open or short circuits).
– Magnetic Reluctance: Too much gap between sensor
coil and reluctor ring. Cracked, broken, or missing teeth on
reluctor ring. Note: Some rings may normally have a gap
or irregular tooth space. This gives the computer cylinder
identification information.
– Hall Effect: Foreign objects in gap between Hall sensor
and shutter assembly. Cracked, broken, or missing blades
on shutter. Note: Some shutter assemblies may normally
have irregular blade spacing. This gives the computer
cylinder identification information.
– Optical: Dirt in the rotor blade slots or light source/
detector assembly. Broken or worn teeth on the distributor
shaft (if used) or sensor shaft.