2003 Toyota Tundra Repair Manual (P/N RM956U)

This 2,807-page PDF package contains Toyota’s 2003 Tundra Repair Manual RM956U material from the two-volume RM956U1/RM956U2 set, a 2003 Tundra New Car Features section, and the model-specific Electrical Wiring Diagram EWD491U. Coverage applies to UCK30/40 and VCK30/40-series trucks in 2WD and 4WD configurations with the 5VZ-FE V6 or 2UZ-FE V8. Drivetrain sections distinguish the R150/R150F manual transmissions, A340E/A340F automatics, and VF2A/VF2BM transfer cases. The New Car Features material also documents 2003-specific changes to ETCS-i, A340 line-pressure control, standard ABS, HVAC, Toyota Vehicle Intrusion Protection (TVIP), cruise control, and the power slide back window.

• Engine and fuel-system repair: Covers compression and valve-clearance inspection, timing-belt replacement, cylinder-head removal, disassembly, inspection and reassembly, separate 2WD and 4WD engine removal procedures, and cylinder-block overhaul for both engines. Supporting sections address SFI, EVAP and PCV systems, cooling, lubrication, ignition, starting, charging, and exhaust/emissions components.
• Transmission and clutch work: Includes clutch-pedal and hydraulic-cylinder service, clutch-unit removal, inspection and installation, internal teardown and reassembly of the R150/R150F manual transmissions, and A340E/A340F diagnostic, valve-body, sensor, unit-removal, and torque-converter procedures.
• Transfer, axle, and driveline service: Details VF2A and VF2BM transfer disassembly, oil-pump and shaft inspection, bearing and seal replacement, propeller-shaft and spider-bearing repair, the A.D.D. (Automatic Disconnecting Differential) control system, and touch-select 2-4/high-low diagnosis.
• Suspension, brake, and steering repair: Covers front hubs and drive shafts, front differential carrier service, standard and LSD rear differentials, wheel alignment, control arms, ball joints, leaf springs, sport-package rear stabilizer components, brake hydraulics and friction parts, Load Sensing Proportioning and Bypass Valve testing and adjustment, ABS actuator and speed-sensor work, power-steering pressure tests and bleeding, vane-pump overhaul, and rack-and-pinion steering gear repair.
• Electrical, body, and HVAC systems: Includes SRS, body electrical troubleshooting, doors, glass, seats, trim, power windows and locks, power slide back window, trailer-towing circuits, air-conditioning diagnosis, refrigerant evacuation and charging, leak testing, compressor and magnetic-clutch work, and heater, cooling-unit, and blower-unit service.

Diagnostic Flow and System Troubleshooting

Toyota’s diagnostic structure covers engine control for both engines, the A340E/A340F transmission, ABS, SRS, Toyota Vehicle Intrusion Protection, and cruise control for each engine application. The workflow moves from customer problem analysis and DTC/freeze-frame capture through symptom confirmation, symptom simulation, problem-symptom tables, circuit or component inspection, repair, and a confirmation test.

The diagnostic pages include check mode, active tests where supported, DLC3 communication checks, ECU terminal data, circuit descriptions, wiring diagrams, connector-face views, and ordered inspection charts. This gives a technician a defined path for separating a sensor or actuator fault from a harness, connector, power-supply, ground, or ECU problem instead of treating a stored code as a parts-replacement instruction.

Mechanical and Drivetrain Repair Depth

The engine chapters go well beyond routine maintenance. Both engine families have dedicated timing-belt, cylinder-head, engine-unit, and cylinder-block sections, with inspection limits, assembly illustrations, non-reusable-part identification, sealant locations, and engine-specific Special Service Tool references. Separate 2WD and 4WD engine-unit procedures account for the driveline and front-axle hardware that changes access and removal work.

The R150/R150F manual-transmission and VF2A/VF2BM transfer sections include internal shaft, gear, synchronizer, bearing, oil-pump, seal, inspection, and reassembly work. A340E/A340F coverage is centered on DTC and freeze-frame diagnosis, preliminary and mechanical tests, stall and line-pressure testing, manual-shift isolation, solenoids and speed/temperature sensors, valve-body service, unit removal and installation, and torque-converter inspection. It does not provide a full internal A340 clutch-pack and geartrain rebuild chapter, an important scope distinction for transmission rebuild buyers.

Wiring Diagrams, Tools, and Specifications

EWD491U is organized around relay locations, electrical wiring routing, system circuits, ground-point maps, power-source current-flow charts, connector illustrations, connector part numbers, and an overall electrical wiring diagram. System-circuit examples include Engine Control for both engines, Electronically Controlled Transmission and A/T Indicator, ABS, SRS, 4WD, and Trailer Towing.

Preparation pages identify Toyota SSTs and their applications, including Valve Clearance Adjust Tool Set 09248-55040, Automatic Transmission Tool Set 09350-30020, LSPV Gauge Set 09709-29018, and Power Steering Pressure Gauge Set 09640-10010. The service-data sections provide component-specific torque tables, pressure-test specifications, fluid types and capacities, wear limits, clearances, electrical test values, and adjustment data across the covered systems.

Safety Reminder: SRS repair must not begin until the ignition switch is in LOCK, the negative battery cable has been disconnected, and at least 90 seconds have elapsed; the restraint system retains backup power that can trigger deployment. The steering-wheel spiral cable must be set to its neutral position before installation or cable disconnection and related faults can result. During front hub and drive-shaft work, the manual repeatedly protects the ABS speed-sensor rotor, oil seals, and boots from scratches or cuts. Transfer installation likewise requires keeping the input shaft from damaging the adapter’s rear oil-seal lip.