EGR DPFE Sensor - Exhaust Noise Heard In Interior
Article No.94-19-22
09/21/94
^ EXHAUST SYSTEM - EXHAUST - TYPE NOISE HEARD IN PASSENGER COMPARTMENT - VEHICLES WITH 2.3L OHC ENGINE AND MANUAL TRANSMISSION
^ NOISE - EXHAUST SYSTEM - EXHAUST - TYPE NOISE HEARD IN PASSENGER COMPARTMENT - VEHICLES WITH 2.3L OHC ENGINE AND MANUAL TRANSMISSION
LIGHT TRUCK:
1994 RANGER
ISSUE:
Customers may complain of an exhaust-type noise heard in the passenger compartment. This may be caused by the design and location of the Differential Pressure Feedback EGR sensor (DPFE) system. With this style of sensor and single ply hoses, exhaust noise is conducted through the mounting studs of DPFE sensor and the walls of the hoses during normal operation.
ACTION:
Replace the DPFE sensor hoses and/or the sensor mounting bracket with revised service parts (the production part number of the DPFE sensor determines installing hoses and mounting bracket or installing hoses only) See Diagnosis and Repair Procedure for details.
DESCRIPTION OF REVISED PART
^ If the vehicle was built with an F1AE-9J460-AA DPFE sensor, replace the DPFE sensor hoses and sensor mounting bracket with revised service parts. The new DPFE hoses are of dual ply design, and the service sensor mounting bracket has thicker isolator mounts to prevent exhaust system noise from conducting into the passenger compartment. Refer to the DIAGNOSIS AND REPAIR PROCEDURES for service details.
^ If the vehicle was built with a F37E-9J460-AA DPFE sensor, replace only the sensor hoses with the new dual ply design hoses. The production sensor mounting bracket has isolator mounts to prevent exhaust system noise from conducting into the passenger compartment. Refer to the DIAGNOSIS AND REPAIR PROCEDURES for service details.
DIAGNOSIS AND REPAIR PROCEDURES
Two different DPFE systems were produced:
^ The early production DPFE sensor (F1AE-9J460-AA stamped on the sensor) and single ply hoses: Exhaust noise is conducted through the mounting studs of the DPFE sensor and the walls of the hoses during normal operation.
^ The latter production DPFE sensor (F37E-9J460-AA stamped on the sensor) with production installed isolators and single ply hoses: Exhaust noise is conducted through the walls of the hoses during normal operation.
1. Verify that the exhaust system is properly installed, and that no Diagnostic Trouble Codes (DTC's) are stored in memory.
NOTE:
THIS TSB WILL ONLY ADDRESS AN EXHAUST SYSTEM NOISE WITH NORMAL DPFE SENSOR OPERATION. IF ANY DTC's ARE STORED IN MEMORY, THEY WILL NEED TO BE CORRECTED BEFORE PROCEEDING.
2. If exhaust system is properly installed, bypass the DPFE sensor operation by performing the following checks:
a. Disconnect both DPFE single ply hoses from the DPFE sensor.
b. Remove the larger hose from the EGR tube, and save.
c. Route and connect the sensor end of the smaller hose to the exposed fitting on the EGR tube so that a vacuum loop is created on the EGR tube.
d. With engine at normal operating temperature, test drive the vehicle under steady and moderate acceleration conditions.
3. Is the exhaust system noise greatly reduced?
a. NO - Clear any DTC's falsely set during the test drive. Reconnect DPFE system and perform additional exhaust system diagnosis.
b. YES - Clear any DTC's falsely set during the test drive, and continue with this procedure.
4. If the vehicle is equipped with the F37E-9J460-AA sensor, go to Step 10. If the vehicle is equipped with the F1AE-9J460-AA sensor, disconnect the DPFE sensor electrical connection at the sensor.
5. Remove and discard the nuts attaching the DPFE sensor (F1AE-9J460-AA) to the mounting bracket.
6. Remove and retain the screws attaching the mounting bracket. Remove the mounting bracket from the dash panel and discard.
7. Attach the new DPFE sensor mounting bracket (F4PZ-9E494-A) on the dash panel location. Tighten mounting bracket screws to 2.5-3.5 N-m (22-31 lb.in.).
NOTE:
THE RUBBER ISOLATOR MAY START TO "WIND-UP" AS THE NUTS ARE BEING TIGHTENED. TO PREVENT THIS FROM OCCURRING, LIGHTLY HOLD (WITHOUT DAMAGING) THE ISOLATORS WITH A PAIR OF PLIERS WHILE TIGHTENING THE NUTS.
8. Install the DPFE sensor (F1AE-9J460-AA) on the new mounting bracket isolator studs and tighten the two new sensor mounting bracket nuts to 2.5-3.5 N-m (22-31 lb.in.).
9. Connect the DPFE sensor electrical connection.
10. Install both dual ply hoses (F4PZ-9P761-A and F4PZ-9P761-B) and connections to the proper fittings of the DPFE sensor.
11. Remove and discard the single ply hose from the fittings of the EGR tube.
12. Connect both dual ply hose connections to the proper fittings of the EGR tube.
13. With engine at normal operating temperature, test drive the vehicle under steady and moderate acceleration conditions.
14. Is the exhaust system noise greatly reduced?
a. NO - Clear any DTC's falsely set during the test drive. Reconnect DPFE system and perform additional exhaust system diagnosis.
b. YES - Clear any DTC's falsely set during the test drive, and return the vehicle to the customer.
Parts Block
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
941922A Perform Diagnostics As 1.1 Hrs.
Outlined, Replace DPFE Hoses
941922B Additional To Install 0.1 Hr.
Mounting Bracket
DEALER CODING
BASIC PART NO. CONDITION CODE
9E494 56
OASIS CODES: 403000, 490000, 497000, 702300