Engine - Fluctuating Idle After Cold Start
Article No.95-23-10
11/20/95
IDLE - FLUCTUATING IDLE RPMS AFTER COLD
START - 4X2 SUPERCAB VEHICLES WITH P225
TIRES, 3.08 OR 3.55 AXLES AND 4.0L ENGINE
LIGHT TRUCK:
1994 RANGER
CALIBRATION:
4-58E-R10
WARNING:
THIS MODIFICATION IS AUTHORIZED ONLY FOR THE LISTED ENGINE. PERFORMING THIS MODIFICATION ON OTHER ENGINE CALIBRATIONS IS UNAUTHORIZED AND COULD CREATE LIABILITY UNDER APPLICABLE FEDERAL OR LOCAL LAWS.
ISSUE:
After a cold start in ambient temperatures between 10°-32°C (50°-90°F) followed by an extended idle, a vehicle may experience a fluctuating idle speed condition. This may be caused by early closed loop operation.
ACTION:
Replace the Powertrain Control Module (PCM) with a new PCM which will increase the time of closed loop operation from 30 seconds to 50 seconds. Refer to the following Service Procedure and Application Chart for service details.
SERVICE PROCEDURE
This procedure is for 4X2 SuperCab vehicles with P225 tires and either 3.08 or 3.55 axles only.
1. If, after a cold engine start-up in ambient temperatures between 10°-32°C (50°-90°F) followed by an extended idle, a fluctuating idle condition is encountered, replace the PCM Refer to the Application Chart for correct usage.
PART NUMBER PART NAME
F47Z-12A650-CRA Powertrain Control Module (PCM)
2. Test start the vehicle and perform the EEC-IV self test. Confirm the fluctuating idle condition has been eliminated and that no Diagnostic Trouble Codes (DTCs) are present. If any DTC appears, refer to the 1994 Engine/Emissions Diagnostic Manual for further diagnostic details.
Obtain an Authorized Modification Decal and list the date, dealer number, and summary of modifications performed. Select a prominent place adjacent to the Vehicle Emission Control Information Decal suitable for installing the Authorized Modifications Decal. Clean the area, install the decal, and cover it with a clear plastic decal shield.
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
952310A Replace Powertrain Control 0.3 Hr.
Module (PCM)
DEALER CODING
CONDITION
BASIC PART NO. CODE
RECAL 08
OASIS CODES: 618400