P0506 Idle Air Control System Low Rpm - Isuzu 2000 Trooper Workshop Manual

Diagnostic Trouble Code (DTC) P0506 Idle Air Control System Low RPM
Circuit Description
The powertrain control module (PCM) controls engine
speed by adjusting the position of the throttle control
valve (DC motor). The throttle motor is a DC motor driven
by one coil. The PCM applies current to the DC motor coil
in position (%) to adjustment the throttle valve into a
passage in the throttle body to air flow. This method
allows highly accurate control of engine speed and quick
response to changes in engine load.
If the PCM detects a condition where too low of an idle
speed is present and the PCM is unable to adjust idle
speed by increasing the throttle position, DTC P0506 will
set, indicating a problem with the idle control system.
Conditions for Setting the DTC
D No TPS, VSS, ECT, EGR, MAF, low voltage, fuel
system, canister purge, injector control, or ignition
control DTCs are set.
D MAP is less than 60 kPa.
D Canister purge duty cycle is above 10%.
D Engine running time is more than 125 seconds.
D Vehicle speed is less than 1 mph.
D Engine coolant temperature (ECT) is above 50°C.
D Ignition voltage is between 9.5 volts and 16.7 volts.
D The throttle is closed.
D EVAP purge duty cycle more than 10%.
D All conditions are met for 10 seconds.
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
D Engine speed is more than 100-200 RPM lower than
desired idle based upon coolant temperature.
Action Taken When the DTC Sets
D The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.
D The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
D DTC P0506 can be cleared by using the Tech 2 "Clear
Info" function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
D Poor connection at PCM or throttle DC motor – Inspect
harness connectors
improper mating, broken locks, improperly formed or
damaged terminals,
connection.
D Damaged harness – Inspect the wiring harness for
damage.
D Restricted air intake system – Check for a possible
collapsed air intake duct, restricted air filter element, or
foreign objects blocking the air intake system.
D Throttle body – Check for objects blocking the ETC
passage or throttle bore, excessive deposits in the
6E–355
D06RY00158
for backed-out terminals,
and poor terminal-to-wire