Service bulletin about the check engine light being activated by a faulty oil pressure switch/sensor.
No: H483 Ref: TIB 12/03/97/NAS TIB 12/04/97/NAS Issue: 2 Date: 01/30/98 Service Action Oil Pressure Switch Replacement AFFECTED VEHICLE RANGE: Defender (LD) RA927939 to VA128421 Discovery (LJ) RA049523 to TA200000 SA500000 to VA557347 TA700000 to WA747771 Range Rover Classic (LH) RA635508 to SA664120 Range Rover (LP) SA300190 to WA379749 Updated information is shown by asterisks. SITUATION: OIL PRESSURE SWITCH LEAKAGE Oil pressure switches on Land Rover vehicles may leak because diaphragm material within the switch does not meet specifications. This can cause oil seepage from the switch cap to the body seal, or from the vent hole around the electrical blade insert. RESOLUTION: REPLACE ORIGINAL SPECIFICATION OIL PRESSURE SWITCHES ON AFFECTED VEHICLES *All vehicles within the above VIN ranges are to be inspected during the next service visit.* If the oil pressure switch has not been replaced with either a new style pressure switch (light gray insert) or with the PRIDE specified switch (black and red insert), replace the switch with STC4104K. PARTS INFORMATION: NOTE: Pressure switch STC4104K is packaged with both a rubber 0-ring (for serpentine belt vehicles) and a copper washer (for V-belt vehicles). STC4104K Oil pressure switch (Replaces AMR2092 and LRNA4641) WARRANTY CLAIMS: * NOTE: Correct Option 2 time will be automatically selected by LRNA warranty computer program based on vehicle upon which procedure has been performed. CAMPAIGN H483 Option 1 Time 0.10 hrs Inspect vehicle and determine correct oil pressure switch is installed. Affix campaign sticker. Option 2 Time 0.55 hrs. Replace Range Rover oil pressure switch Option 2 Time 0.45 hrs. Replace Discovery and Range Rover Classic oil pressure switch Option 2 Time 0.30 hrs. Replace Defender oil pressure switch All vehicles included in above VIN ranges are to be inspected and oil pressure switch replaced if indicated by inspection results.* REPAIR PROCEDURE: INSPECTION OF VEHICLE OIL PRESSURE SWITCH 1. Inspect oil pressure switch to determine if original switch has been replaced with correct PRIDE switch (LRNA4641) or H483 Campaign switch (STC4104K). 2. Identify switch LRNA4641 by the following characteristics: ^ Switch has dark plastic housing with red silicon ring-seal next to the hex of the switch body. ^ Switch body hex is 11/16 inches. ^ Male spade electrical connection is riveted to housing and the spade is off-set from center. 3. Identify switch STC4104K which may have been installed from parts stock, by the following characteristics: ^ Switch has white/light gray plastic housing. ^ Hex is 15/16 inches. ^ Male electrical connector comes through the center of the plastic housing. *4. If switch is identified as LRNA4641 or STC41O4K, complete campaign sticker and affix to front cross member. No further action is required.* RANGE ROVER OIL PRESSURE SWITCH REPLACEMENT 1. Ensure that radio code is available and disconnect negative terminal from battery. 2. Remove upper fan shroud, fan and serpentine belt. 3. Remove serpentine belt tensioner assembly (one bolt). 4. Disconnect ground strap from alternator bracket to damper shock support (one bolt). 5. Disconnect alternator wiring harness. 6. Remove two bolts securing wiring harness shield to alternator bracket. 7. Remove four bolts securing alternator bracket to cylinder head. 8. Remove alternator assembly. 9. Relieve cooling system pressure and loosen hose clamp at water pump for access to oil pressure switch. 10. Disconnect electrical connector from switch terminal and remove oil pressure switch and 0-ring. 11. Obtain new oil pressure switch and ensure that 0-ring is installed. CAUTION: Do not use any thread sealant on threads of oil pressure switch. 12. Inspect the threads in the front cover, and clean if necessary. 13. Lubricate new 0-ring with engine oil and install oil pressure switch and tighten until 0-ring is compressed. 14. The installed torque of the pressure switch should be 14 to 16 Nm. (10 to 12 lbf. ft.). 15. Apply electrical connector grease ( LRNASGP2) into the female electrical connector and install on switch. 16. Position and tighten hose clamp on water pump. 17. Install alternator assembly and bracket to head with four bolts. Torque to 25 Nm. (18 lbf. ft.). 18. Install and tighten two bolts securing wiring harness shield to alternator bracket. 19. Connect and tighten alternator leads. 20. Connect ground strap from alternator bracket to damper shock mount. 21. Install serpentine belt tensioner assembly. Torque to 39 Nm. (29 lbf. ft.). 22. Install serpentine belt, fan and fan shroud. 23. Connect battery negative terminal. 24. Reset windows/sunroof and code radio. 25. Check engine oil level and replenish as necessary. DISCOVERY, DEFENDER AND CLASSIC OIL PRESSURE SWITCH REPLACEMENT SERPENTINE BELT ENGINE 1. Place vehicle on lift and raise vehicle. 2. Remove electrical connector from oil pressure switch. 3. Remove old oil pressure switch and 0-ring. CAUTION: Do not use thread sealant on threads of oil pressure switch. 4. Inspect the threads in the front cover, and clean if necessary. 5. Lubricate new 0-ring with engine oil. 6. Install new oil pressure switch and tighten until 0-ring is compressed. 7. Tighten the oil pressure switch to 14 to 16 Nm. (10 to 12 lbf. ft). 8. Apply electrical connector grease into the female electrical connector and install on switch. 9. Lower vehicle and top off engine oil if necessary. V-BELT ENGINE 1. Locate oil pressure switch on oil pump housing, remove electrical connector, remove and discard oil pressure switch and copper crush washer. 4. Inspect threads in oil pump housing, and clean if necessary. CAUTION: Do not use thread sealant on threads of oil pressure switch. 5. Install new oil pressure switch with new copper crush washer and torque to 20 to 25 Nm. (15 to 19 lbf. ft.). 6. Apply electrical connector grease into the female electrical connector and install on switch. 7. Top off engine oil if necessary. CAMPAIGN ADMINISTRATION 1. Apply a completed campaign label (LRN0001LABEL) to the front cross member under the hood to identify that Service Action H483 has been performed. ```