ECM - Engine 'Flare' or Surge With Throttle Closed

No: 19/04/97/NAS

Ref: WSM section 19
TIB 19/08/96/US

Issue: 2

Date: 06/20/97

PRIDE IV 6-11

Engine Speed Fluctuation at Moderate Speed Closed Throttle

AFFECTED VEHICLE RANGE:
DISCOVERY (LJ) 1997 MY Advanced EVAPS Equipped
VIN: up to VA727076 Automatic
up to VA726789 Manual
up to VA558898 Manual and Automatic

SITUATION:

IDLE FLUCTUATES DURING MODERATE SPEED CLOSED THROTTLE OPERATION There have been reports of engine flare or surge when the vehicle is decelerating. The engine speed may fluctuate between 1200 and 1600 rpm (up to 400 rpm total fluctuation) when the throttle is closed and the vehicle speed is between 35 and 50 mph (56-80 kph.). This may occur in GEMS equipped, Advanced EVAPS vehicles in the above VIN ranges.

RESOLUTION:

REPLACE PROM

Upon customer complaint only, install a new PROM set which has been developed to eliminate the problem. Replace the PROM set using established Operation Pride procedures. (TIB 19/08/96/US)

PARTS INFORMATION:

PRM9640 PROM (Automatic)
PRM9641 PROM (Manual)
LRNASTATK Anti-Static Mat

WARRANTY CLAIMS:

18.30.89/26 ............... Time 0.50 hrs.
Fill out DPR and FAX to LRNA, Replace GEMS PROM

COMP CODE: .............. 7G1A

Normal warranty policy and procedures apply

REPAIR PROCEDURE:

REPLACE PROM

NOTE:
Make sure to complete the DPR and FAX to LRNA.

1. Call the GEMS HelpLine.

2. The HelpLine will issue a new specification PROM set that will eliminate the concern.

3. Use procedures outlined in earlier phases of Operation Pride to replace PROM set.
(TIB 19/08/96/US)

4. Following installation of the PROM set, start and warm up the vehicle from full cold to hot at idle, in Drive with the Park Brake applied. This will adapt the engine management IACV system and minimize any noticeable changes to the customer upon return of the vehicle.