MIL ON - DTC P0505 (IACV-AAC Valve) Idle Control System

Classification:
EC97-031

Reference:
NTB97-094

Date:
January 15, 1998

1996-97 TRUCK WITH MIL "ON" AND P0505 STORED IN ECM

APPLIED VEHICLE:
All 1996-97 Truck (D21)

SERVICE INFORMATION

If a 1996-97 Truck has a MIL "ON" and DTC P0505 stored in the ECM, the cause may be the IACV-AAC valve. Use the information in this bulletin to repair the vehicle.

SERVICE PROCEDURE

1. Check the IACV-AAC valve and ECM wire harness for an open or shorted circuit (refer to the service manual diagnosis procedures on pages EC-210 to EC-213 of the 1996 Truck Service Manual or pages EC-221 to EC-225 of the 1997 Truck Service Manual).

A. If the wire harness has an open or shorted circuit, repair the harness as required and repeat step 1 to verify the harness repair and IACV-AAC valve operation.





B. If the wire harness is OK, replace the IACV-AAC valve with the countermeasure valve (see Figure 1) and proceed to step 2.

2. Check and adjust engine base idle speed using the following procedure.

IMPORTANT:
The air cleaner assembly must be installed when adjusting the engine base idle speed.

With CONSULT:

A. Connect CONSULT.

B. Start engine and warm it up to operating temperature.

C. Select "Work Support" mode.

D. Select "Ignition Timing Adjust" mode.

E. Touch "Start"





F. Use idle speed adjusting screw to adjust base idle to 750 +/- 50 RPM (see Figure 2).

Without CONSULT:

A. Start engine and warm it up to operating temperature.

B. Stop engine and disconnect throttle position sensor.

C. Start engine and check base idle speed.

D. Use idle speed adjusting screw to adjust base idle to 750 +/- 50 RPM (see Figure 2).

E. Stop engine and reconnect throttle position sensor.





PARTS INFORMATION

CLAIMS INFORMATION

When applicable, standard claims coding applies.