Porsche 928, 928 S, 928 S4, 928 GT, and 928 GTS 1978–1995 Workshop Manual (P/N W 42-608-126-i)

The supplied PDF package is a factory Porsche 928 workshop-manual compilation covering early 928 and 928 S systems as well as later S4, GT/Club Sport, and GTS configurations. Individual sections identify model-year and component changes rather than treating every car as mechanically identical. Porsche states that the workshop manual was for internal use by its dealer organization, so this material is best suited to professional technicians and experienced owners who have the required measuring equipment, lifting facilities, and factory-style diagnostic tools.

• 1,818 PDF pages total — 26-page combined table of contents; Volume I-A: 306 pages; Volume II: 397 pages; Volume III: 276 pages; Volume IV: 458 pages; Volume V: 322 pages; Volume VI: 29 pages; Volume VII: 4 pages. The embedded document text identifies Print No. W 42-608-126-i.
• Fuel and engine-management repair covers CIS, AFC/L-Jetronic, LH-Jetronic, and EZK systems, including fuel-delivery and pressure testing, injector and air-flow sensor service, idle/CO adjustment, oxygen-sensor checks, ignition testing, and cruise-control troubleshooting.
• Factory diagnosis includes LH and EZK fault-code lists, actuator and input-signal checks, knock detection, fault-memory handling, Porsche System Tester 9288 procedures, 19-pin diagnostic-socket references, and Special Tool 9540 checks for the alarm system.
• Manual and automatic drivetrain work includes clutch inspection and bleeding, G28 transmission disassembly and adjustment, A28 torque-converter and transmission repair, valve-body and clutch-pack service, central-tube inspection, ring-and-pinion setup, limited-slip differential repair, and PSD diagnosis and bleeding.
• Chassis, body, HVAC, and electrical procedures cover suspension and wheel bearings, alignment, RDK and ABS diagnosis, hydraulic brakes, steering, R12/R134a air conditioning, structural body-section replacement, glass and sunroof work, airbags, seats, instruments, central locking, alarms, lighting, and wiring-harness repair.
• Important scope limit: the files start with Volume I-A. The Volume I engine-mechanical chapters referenced in the contents — crankcase, crankshaft and pistons, cylinder heads and valve drive, lubrication, and cooling — are not included. Volume VII lists model-specific wiring diagrams but contains only the cover and contents pages, not the diagram sheets themselves.

Fuel, Ignition, and Electronic Diagnosis

The fuel-system material separates early CIS/AFC hardware from LH-Jetronic applications and the later S4/GT/GTS equipment. It documents component removal and installation, fuel-path layouts, pressure and leakage tests, control-unit coding, sensor checks, and fault isolation. The diagnosis pages distinguish earlier fault-memory access from the 1989-on 19-pin tester connection and include K/L diagnostic-line checks for the LH and EZK control units.

Useful electrical references include the CIS and AFC hose diagrams, the fuel-tank breather layout, the Tempostat control-unit pin assignment, RDK control-unit connector assignment, central-warning-unit black- and yellow-plug connection plans, and the model 87/88 circuit-diagram correction. Exploded assembly views and component-location drawings support the repair procedures throughout the drivetrain, chassis, body, and electrical volumes.

Drivetrain, Chassis, and Body Repair Depth

The transmission volumes go beyond routine fluid service. They cover removal, teardown, inspection, reassembly, adjustment, and operational testing of manual and automatic units, including 1987-on changes and the A28.18 GTS automatic. Differential work includes bearing and shim selection, backlash setup, central-tube checks, 40-percent limited-slip and proportional-slip units, and PSD hydraulic diagnosis with the related test equipment.

The manual also preserves component-specific repair cautions. It warns that an incorrectly seated torque converter can destroy its drive dogs and the automatic transmission's primary pump. During final-drive setup, an incorrect shim split can clamp the matched drive pinion and ring gear, risking damage to the gear set.

Chassis coverage includes pre-1986 and 1986-on suspension differences, adjustable and non-adjustable struts, brake-caliper variants, steering pressure testing, RDK fault diagnosis, and air-conditioning pressure/temperature charts. Body sections provide factory repair dimensions, panel-replacement procedures, foam-filled-cavity precautions, bonded-glass service, and airbag-system diagnosis. Related torque tables, fluid capacities, test pressures, clearances, wear limits, alignment data, and electrical test values are supplied for the assemblies actually included.

Fuel systems, PSD hydraulics, brakes, refrigerant circuits, airbags, and heavy drivetrain components require proper isolation, pressure relief, lifting equipment, and protective gear. Follow the manual's system-specific safety instructions and use suitably rated workshop equipment before beginning repair work.