SUBJECT: Leak Detection Pump (LDP) Dealer Test Mode

NO: 18-17-97

GROUP: Vehicle Performance

DATE: May 2,1997

MODELS: 1997 (FJ) Avenger/Sebring/Talon 1997 (JA) Cirrus/Stratus/Breeze 1997 (JX) Sebring Convertible 1997 (NS) Town & Country/Caravan/Voyager 1997 (PL) Neon 1997 (ZJ) Grand Cherokee NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A LEAK DETECTION PUMP (LDP).

DISCUSSION: A new test has been added to the DRB II to verify repairs made to the evaporative emission system on LDP equipped vehicles. This test, when used after the standard pressurization test to locate an evaporative leak, is very effective in verifying the repair. The following information will list the test procedures along with the differences between passenger cars/minivan and Jeep vehicles.

EQUIPMENT REQUIRED: 1 CH6000 Scan Tool (DRB II ) 1 CH7035 General Purpose Interface BusCable (GPIB) 1 CH7000/7001 J1962 Cable NOTE: THE DRB III IS REQUIRED TO PERFORM THIS TEST. THE MDS SYSTEM MUST BE OPERATING WITH RELEASE 21 OR HIGHER AND TIL CD RELEASE1130 OR HIGHER MUST BE INSTALLED TO UPDATE THE DRB III TO RELEASE 22.1.

TEST PROCEDURE: This test temporarily makes changes to the PCM operating mode to allow the LDP monitor to run. It is critical that the test not be interrupted. If an interruption occurs, the MIL will stay illuminated for 8 to 10 miles of driving with no DTC's. To eliminate this condition, rerun the test, without interruption, to allow the PCM to return to its normal operating mode. This test should only be used to verify that an evaporative system leak, as indicated by the OBD II system, is repaired. NOTE: THE PCM KNOWS IF THE VEHICLE IS LDP EQUIPPED OR NOT. THIS CAN BE SEEN ON THE DRB 111 IN THE VEHICLE LEARNED CONFIG SCREEN. 1. Connect the DRB 111 (Scan Tool) to the vehicle and power it up. 2. From the MAIN MENU, select DRB 111 Standalone 3. From the STAND ALONE MAIN MENU, select 1994 - 1998 Diagnostics. 4. From the SELECT SYSTEM screen, select Engine. 5. Press enter twice to go to the SELECT FUNCTION screen. 6. From the SELECT FUNCTION screen, select System Test. 7. From the ENGINE SYSTEMS TEST screen, select LDP Dealer Test Mode. 8. Once in the LDP Dealer Test Mode program, the DRB 111 will prompt the operatorand explain what will take place during the test. 9. During this test mode, the MIL will flash on and off. NOTE: DO NOT INTERRUPT THIS TEST WHILE IT IS IN PROGRESS. DO NOT REV THE ENGINE OR DRIVE THE VEHICLE. 10. When the test finishes the DRB 111 will indicate if the test passed or failed. When complete, press the page back key and follow the remaining screen prompts. NOTE: IF THE TEST FAILS, IT WILL LOG A SMALL LEAK DTC FOR PASSENGER CAR/MINIVAN (EVEN IF A LARGE LEAK EXISTS). FOR ZJ, THE SYSTEM WILL LOG EITHER A SMALL LEAK OR LARGE LEAK - 1 TRIP FAILURE -DEPENDING ON WHAT THE TEST FOUND. If a leak is found, further diagnosis will be required to determine where the leak is located. Use the standard pressurization test with Miller Tool 6872A and the Paradise 300 Ultra-Sonic leak detector to find leaks in the evaporative system. NOTE: IF THE DEALER TEST MODE IS RUN MULTIPLE TIMES TO VERIFY REPAIRS, THE VEHICLE MAY MOMENTARILY RUN ROUGH UNTIL THE VAPOR PRESSURE IN THE TANK IS PURGED. BEFORE EXITING THE COMPLETED TEST, ALLOW THE ENGINE TO IDLE FOR A MINIMUM OF 30 SECONDS.

POLICY: Information Only