Starting System - No Crank/No Start/Security Lamp ON/OFF

SOURCE: Isuzu Service News

TITLE: No Crank, No Start, Security Light On or Off

APPLIES TO: 03-05 Ascender

SERVICE TIP:

Condition:

No Crank, No Start, No DTCs. When the vehicle is placed into the "Park" position, circuit 1433 (4.2L) or circuit 1786 (5.3L on 2005) has 12 volts applied to the PCM through the Park Neutral Position Switch (PNP). This is done so the PCM acknowledges the vehicle is in "Park" prior to enabling the starter relay command. These two circuits may also be referred to as the "Clutch Start Switch Signal". Even though the vehicle has an automatic transmission, these two circuits need to be validated using a DMM (Digital Multimeter).

Correction:

To confirm the vehicle is placed in the "Park" position, inspect circuit 1433 (4.2L) or circuit 1786 (5.3L) for 12 volts (using a DMM) when the Park Neutral Position Switch (PNP) is placed into the "Park" position. This should be inspected even if the Tech 2 data is reading correctly.