Mercedes-Benz S420 Service & Repair Manual Collection (1998)

The repair articles work alongside system wiring, diagnostic charts, service specifications, and general workshop references. These are Mitchell Repair Information Article Print files compiled as an aftermarket collection, rather than one Mercedes-Benz factory publication.

Coverage limits: Primary coverage is the 1998 S420. Additional models appear in shared articles; the collection is not a complete service set for each of them. Individual article applications and production-date breaks govern which procedures apply. The January 2002 Motorist Assurance Program inspection standards and all-makes tutorials are general references rather than S420-specific factory procedures.

PDF Search, Navigation and File Contents

Text search and diagram detail: Article prose is searchable, but many wiring labels and diagnostic tables are embedded as images and fall outside PDF text search. None of the files has embedded PDF bookmarks. Small labels in the engine, transmission, and climate-control wiring sheets require zooming.

The ZIP contains 74 printable English PDFs totaling 1,634 pages, including the general-reference articles and inspection guidelines listed above. The Steering and Suspension Uniform Inspection Guidelines files repeat the same reference material.

Engine, Transmission and Vehicle-System Coverage

The following highlights are a selected content preview. Other included topics include maintenance-reminder resets and injector-waveform interpretation.

• Engine repair: Step-by-step procedures for engine removal, cylinder-head work, crankshaft seals, timing-chain tensioners and guides, camshaft adjusters, camshafts, and oil-pan service.

• Engine management: Engine 119 ME-SFI code retrieval and clearing, symptom diagnosis, ECM version coding, and fuel-injection, ignition, electronic-accelerator, cruise-control, injector, and fuel-pump tests.

• Automatic transmission: W5A580/722.6 adaptation, limp-home and symptom diagnosis, TCM inputs and outputs, solenoid and circuit testing, fluid service, linkage adjustment, and removal/installation.

• Brakes and traction control: Disc-brake service and overhaul, ABS/ASR V/BAS/ESP diagnosis by equipment level, hydraulic-unit bleeding, fault-code interpretation, and electrical testing.

• Steering and suspension: Electronic power-steering diagnosis, front and rear suspension removal, rear level-control pressure release and refill, axle-shaft service, riding-height checks, and wheel alignment.

• Climate control: Front and rear automatic A/C version coding, self-diagnostics, sensor and flap testing, unit service, refrigerant handling, and compressor-clutch procedures.

• Body and electrical systems: PSE central-locking, drive-authorization, restraint, and comfort-system diagnostics, plus starting/charging checks and parasitic-load testing.

Because the procedures are condensed and many test paths assume an HHT, socket box, DVOM, refrigerant service equipment, or safe vehicle lifting, this set is suited to professional technicians and experienced owners already comfortable with late-1990s Mercedes systems.

Engine Repair Depth and Component Inspection

The engine article includes valve-timing checks and camshaft basic timing using Camshaft Pins 119 589 00 15 00. Inspection tables address cylinder-head and block condition, bore and piston groups, bearings, ring clearances, wear limits, lubrication data, and tightening sequences.

The chapter warns that a camshaft can fracture if it is bent during bearing-cap installation. The transmission-removal article separately identifies metal trapped in a contaminated torque converter as a cause of repeat transmission failure after repair.

Engine procedure limits: The model-specific article does not provide removal/installation procedures for the intake manifold, complete timing chain, water pump, or oil pump. Its companion overhaul chapter provides general piston-engine guidance.

Diagnostic Applications and Test Equipment

The identification material separates chassis, engine, fuel-system, ignition, and transmission applications before a repair procedure or test chart is selected. This helps match the documented tests to the vehicle and equipment being diagnosed.

The Engine 119 diagnostic article spans 1996–99 and distinguishes systems before and after June 1996, plus the SL500 change at September 1997. Equipment callouts include Hand-Held Tester 965 589 00 01 00, Multiplexer Cable 965 589 00 40 00, and Socket Box 129 589 00 21 00.

The shared ABS article also contains ETS material for E320 AWD applications; those sections do not describe an additional S420 drivetrain variant.

Comfort Systems, Restraints and Central Locking

Separate articles address air bags and emergency tensioning retractors, Drive Authorization System/keyless entry, anti-theft functions, power seats, power mirrors and steering-column adjustment, window/sunroof synchronization and calibration, and wipers.

Several accessory chapters emphasize diagnosis and wiring rather than component removal. The pneumatic door-lock article lacks its own 1998 wiring sheets, although the separate S420 system-diagram file includes the power-door-lock circuit.

Air-bag, brake-hydraulic, refrigerant, loaded-suspension, and transmission-removal work requires the article-specific precautions and proper support, test, and service equipment.

System Wiring and Diagnostic Illustrations

Powertrain: Examples include the 4.2L Engine Performance Circuits and 1997–99 S420/S500 Transmission Wiring Diagram, supported by connector views and component locators.

Brakes and climate control: The collection includes Anti-lock Brake Circuits with ASR/ESP and 1998–99 S-Class Automatic A/C-Heater Wiring Diagrams.

Restraints and locking: Additional examples include the S320/S420/S500 Air Bag System Wiring Diagram and Central Locking System Vacuum Diagram. Diagnostic flowcharts and system test tables accompany the relevant articles.

Examples from the Compression and Ignition Tables

For the S420’s 119.981 engine, the compression table lists a normal pressure range of 145–203 psi (10–14 bar), with a maximum cylinder-to-cylinder difference of 22 psi (1.5 bar).

The 1998 ignition specifications list a spark-plug gap of .032 in. (0.81 mm).