Table C-1A Electrical Load Idle-Up Signal Check

Diagnostic Chart:

Wiring Diagram:

Circuit Description

The Powertrain Control Module (PCM) receives an idle-up signal at from the diode module. This signal is present whenever one or more of the following systems is turned ON or operated.

^ Headlights

^ Rear Window Defogger

^ Heater Blower Motor

The Idle Speed Control (ISC) Motor will increase the throttle valve opening to compensate for the additional electrical load(s).

Diagnostic Aids

Check for any of the following items:

^ Inspect the wiring harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connections before component replacement.

^ A short to ground on the BRN/YEL wire may cause an open TAIL fuse.

^ An intermittent malfunction, may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation.

If any wiring repairs need to be made, Refer to Repair Procedures in Electrical Diagrams.

Test Description

The numbers below refer to the step numbers in the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. Check for electrical load Idle up signal to the PCM.

7. This step checks the separate systems.