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Engine - Lack of Power After Extended Idle/DTC 121 Set

Article No.
94-16-17

08/10/94

^ LACK OF POWER - AFTER AN EXTENDED IDLE AT HIGH AMBIENT TEMPERATURES (GREATER THAN 95 DEGREES F/35 DEGREES C) - VEHICLES WITH 2.3L OHC AND A4LD AUTOMATIC TRANSMISSION

^ MALFUNCTION INDICATOR LAMP (MIL) - INTERMITTENT/CONTINUOUS MIL AND DIAGNOSTIC TROUBLE CODE (DTC) 121 IN COLD AMBIENTS - 2.3L OHC ENGINES PREVIOUSLY SERVICED BY TSB 93-26-13

LIGHT TRUCK:
1993-94 RANGER

CALIBRATION:
3-50S-R10, 3-50S-R00, 4-50S-R00, 4-50S-R11

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.

This TSB article is being republished in its entirety to provide the latest "C" level PCM to eliminate possibility of DTC 121.

ISSUE:
A lack of power or poor acceleration may occur after an extended idle at high ambient temperatures of 95~F (35~C). This may be caused by the operating strategy of the powertrain control module.

ACTION:
Refer to the following procedure for diagnostic and service details.

DIAGNOSTIC TROUBLE CODE CHECK

Perform normal diagnosis to be sure that no fault is present.

^ Refer to the Powertrain Control Emissions Diagnosis Car/Truck Service Manual for Malfunction Indicator Lamp (MIL) concerns.

^ Check for Diagnostic Trouble Codes (DTC's) as directed. If any DTC's are found, they must be repaired before proceeding.

^ If no DTC's are found and the condition still exists, continue with the "Diagnostic Routines" in Section 2A of the Powertrain Control Emissions Diagnosis Car/Truck Service Manual before continuing with the following diagnosis.

POWERTRAIN CONTROL MODULE (PCM) CALIBRATIONS - 1993 MODEL YEAR

1. Check to see if the 1993 vehicle has service replacement PCM (F3PZ-12A650-EA) installed.

2. If the 1993 vehicle has the service replacement PCM installed, return the vehicle to the customer.

POWERTRAIN CONTROL MODULE (PCM) CALIBRATIONS - 1994 MODEL YEAR

1. Check to see if the 1994 vehicle has service replacement PCM (F47Z-12A650-AFC) installed.

2. If the 1994 vehicle has the service replacement PCM installed, return the vehicle to the customer.





3. If the vehicle does not have the service replacement PCM installed, install the correct replacement PCM. Refer to the PCM Replacement Chart for correct parts usage.





Obtain an Authorized Modifications Decal and list the date, dealer number, and summary of alterations 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.

PART NUMBER PART NAME CLASS

F3PZ-12A650-EA Powertrain Control Module A
(PCM)
F47Z-12A650-AFC Powertrain Control Module
(PCM) A

OTHER APPLICABLE ARTICLES: NONE
SUPERSEDES: 93-26-13
WARRANTY STATUS:
Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage

OPERATION DESCRIPTION TIME
941617A Perform EEC-IV Quick Test, 0.8 Hr.
Remove PCM To Check
Part Number and Replace If
Necessary, Perform Final
Quick Test

DEALER CODING
BASIC PART NO. CONDITION CODE
RECAL 08

OASIS CODES: 614000, 614500, 614600, 690000