SUBJECT: Check Engine Light On "Evap Purge Flow Monitor Failure" ­ Flash Code 31

NO: 18­26­94 Rev. A

GROUP: Veh. Performance

DATE: Dec 23 1994 THIS BULLETIN SUPERSEDES SERVICE BULLETIN 18­26­94 DATED DEC. 9, 1994 WHICH S D BE REMOVED FROM YOUR FILES. THE MODEL APPLICATION NOTE HAS BEEN REVISED. CHANGES ARE HIGHLIGHTED WITH **ASTERISKS**.

MODELS: 1995 (PL) Neon NOTE: THIS BULLETIN APPLIES TO VEHICLES BUILT ON OR AFTER AUG. 6, 1994 (MDH 08­06­XX) THROUGH NOV. 23, 1994 (MDH 11­23­XX), **AND ALSO APPLIES TO ANY VEHICLES WHERE THE PCM WAS REPL ACED USING SERVICE BULLETINS 18­18­94 OR 18­25­94.**

SYMPTOM/CONDITION: Check Engine Light on, Diagnostic Trouble Code "Evap Purge Flow Monitor Failure" and/or Flash Code 31 is set.

DIAGNOSIS: Using the Mopar Diagnostic System (MDS) or the Scan Tool (DRBIII) and appropriate Diagnostic Procedure Manual, verify that all engine systems are functioning correctly. If Diagnostic Trouble Codes (DTC's) other than 31 are present, record them on the repair order for future reference and repair as necessary. Verify that the Purge System is functioning properly. Disconnect the purge solenoid hose at the canister. The line should be free of carbon pellets (a light amount of dust is normal). Start the engine. After about 90 seconds, the Duty Cycle Purge Valve should start to cycle. At the open end of the hose one should feel a steady stream of brief vacuum pulses in response to the pulsing of the valve. This is normal and the purge system is functioning properly. If no other codes other than 31 are present, proceed with the following repair.

PARTS REQUIRED: 1 CH6000 Scan Tool (DRBIII ) 1 CH7035 General Purpose Interface Bus Cable (GPIB) 1 CH7000 J1962 Cable 1 4669020 Label ­ Authorized Software Update 1 4275086 Label ­ Authorized Modification

REPAIR PROCEDURE: This bulletin involves reprogramming the powertrain control module with new software. NOTE: THE MOPAR DIAGNOSTIC SYSTEM IS REQUIRED TO PERFORM THE FOLLWOING REPAIR. THE SYSTEM MUST BE OPERATING WITH RELEASE 15 OR HIGHER INSTALLED. This repair involves selectively erasing and reprogramming the Powertrain Control Module with new software (calibration change). 1. Connect the MDS (Mopar Diagnostic System) and DRBIII (Scan Tool) to the vehicle and power them up. 2. Use the arrow keys and select #2 MDS DIAGNOSTICS on the DRBIII MAIN MENU Screen. 3. Use the arrow keys and select DIAGNOSTIC MENU on the MDS, then press NEXT MENU. 4. Use the arrow keys and select CONTROLLER PROGRAMMING on the MDS, then press NEXT MENU. 5. Use the arrow keys and select PROGRAM CONTROLLER PART on the MDS, then press NEXT MENU. 6. Follow the steps presented on the MDS and DRBIII which will allow the DRBIII to obtain the current part number of the controller. 7. The MDS will display the part number of the controller on the vehicle and the appropriate replacement part number, then press NEXT MENU to begin programming. If the controller on the vehicle has already been updated or programmed, a NO UPDATES AVAILABLE message will be displayed. Check the part number of the controller on the vehicle and compare it to the part number displayed. If the controller has already been updated, proceed to step 9. 8. The MDS and DRBIII will prompt for any operator action needed during the remainder of the programming process. NOTE: THE FOLLOWING STEPS ARE REQUIRED BY LAW. 9. Type the necessary information on the "Authorized Software Update Label" and attach it to the PCM and cover the label with a clear plastic sticker. 10. Type the necessary information on the Authorized Modification Label and attach the label near the VECI Label.

POLICY: Reimbursable within the provisions of the warranty.