Introduction

Note: Enter this pinpoint test only when directed here from the symptom flowcharts.

Remember
This pinpoint test is intended to diagnose only the following:
- harness circuits
- relay
- heater
- Powertrain Control Module (PCM)






Description
To reduce white smoke during long idle periods at low ambient temperatures, the PCM will activate the intake air heater. Specific conditions must be present before the heater is activated:
- ambient temperature must be below 0°C (32°F)
- Engine Oil Temperature (EOT) must be below 55°C (131°F)
- Vehicle Power (IVPWR) must be between 11.8 and 15.0 volts

DTC Description
P0541 - Monitor circuit open fault
P0542 - Monitor power short fault
P0640 - Relay coil circuit fault