B2500 SX Regular Cab 2WD L4-2.5L VIN C (1999)
PROM - Programmable Read Only Memory: All Technical Service Bulletins
Engine Controls - Delayed Return to Idle/DTC P0320 Set
01-002/99
1998-99 B-SERIES DELAYED RETURN TO IDLE AND/OR MIL "ON" DTC P0320
APPLICABLE MODELS:
All 1998-99 B-2500 with manual transmission (3.73 axle ratio only).
DESCRIPTION
Some vehicles may exhibit a delay at 1300-2000 engine rpms before returning to normal idle. The condition occurs on closed throttle deceleration in
neutral or with the clutch depressed. There may also be illumination of the Malfunction Indicator Lamp (MIL) and Diagnostic Trouble Code (DTC)
P0320 may be stored in memory. These conditions may be caused by the Powertrain Control Module (PCM).
Customers having this concern should have their vehicle repaired using the following procedure.
NOTE:
This modification will only correct this specific condition.
WARNING:
This modification is authorized only for the listed engine(s). Performing this modification on other engine calibrations is unauthorized and could
create liability under applicable federal or local laws.
REPAIR PROCEDURE
NOTE::
This modification should only be performed if all other components related to idle control have been verified to be working properly. (See
diagnostic index in section 01 of Workshop Manual).
1.
Verify customer complaint.
2.
Select the appropriate card (SST part number 49G0-88-016) and reprogram the PCM using one of the following calibrations. Refer to the "IN-Car
Flash Procedure".
^
9B1M-AB (Federal)
^
9B1M-BA (California)
PCM replacement is not authorized by this Service Bulletin. Refer to section (01) of the Workshop Manual for diagnostic procedures if PCM
hardware concerns exist.
3.
Verify repair.