1988 Jeep Cherokee, Comanche, Wagoneer, Wrangler Repair Manual OEM

• Covers 1988 Jeep Cherokee, Comanche, Wagoneer, and Wrangler service information for the 2.5L VIN H TBI, 4.0L VIN M MPFI, and 4.2L VIN C 2-barrel engine configurations.
• Documents engine removal, cylinder-head and valvetrain repair, timing-system service, piston and crankshaft inspection, oil-pump work, and general four- and six-cylinder overhaul procedures.
• Separates the 2.5L TBI CEC coverage for Cherokee/Comanche from the 4.0L MPFI CEC coverage for Cherokee/Comanche/Wagoneer, with ECU pinouts, sensor and relay tests, diagnostic charts, vacuum diagrams, and system wiring schematics.
• Adds two levels of AW4 automatic-transmission information: electronic diagnosis in the main manual and a dedicated ATSG booklet covering removal, teardown, subassembly overhaul, valve-body service, and final assembly.
• Extends repair coverage to brake hydraulics, clutch service and bleeding, Dana axles and limited-slip differentials, driveshafts and universal joints, steering, front suspension, wheel alignment, and Command-Trac, NP207/231, and NP/NV242 transfer-case diagnosis and overhaul.
• Supplies hundreds of technical figures, component-location views, flowcharts, torque and specification tables, and Cherokee/Wagoneer full-vehicle wiring diagrams in a 1,492-page PDF set.

Engine, Fuel, and Control-System Coverage

This set combines a 1,380-page Jeep service reference compiled by Pacific Coast Manuals with a separate 112-page ATSG JEEP AW-4 transmission booklet. The first volume provides broad 1988 service coverage; the second adds bench-level AW4 repair information. Its AW4 material applies to AW4-equipped Cherokee, Comanche, and Wagoneer applications, not the Wrangler.

Mechanical engine chapters begin with VIN and application identification, then cover manifolds, cylinder heads, valvetrain and lifters, front covers and seals, camshaft and timing components, pistons, rods and rings, crankshafts and bearings, rear seals, and oil pumps. Separate four- and six-cylinder removal articles lead into general overhaul material with component-specific torque tables, clearance data, inspection limits, lubrication information, and wear specifications. Tool references include J-21884 for lifter service and J-21719-01 for vibration-damper removal.

The computerized emission control material is configuration-specific. The 2.5L TBI CEC section is labeled for Cherokee and Comanche; the 4.0L MPFI CEC section is labeled for Cherokee, Comanche, and Wagoneer. The 4.2L coverage is for a two-barrel-carbureted application, so this is not TBI or MPFI coverage across every model. Diagnostic material addresses ECU and diagnostic connectors, MAP and throttle-position sensors, coolant and manifold-air temperature inputs, oxygen-sensor heater operation, EGR controls, injectors, relays, ignition, and fuel-pressure testing.

Transmission, Transfer Case, and Driveline Repair

AW4 diagnostics in the main volume include TCU connector views, solenoid and sensor circuits, gear-select, brake-switch, and TPS checks, plus Code 700, 702, 703, and 705 flowcharts and schematics. The ATSG booklet continues with preliminary checks, manual-shift, hydraulic-pressure, stall, time-lag, and road tests before transmission and torque-converter removal. Its internal repair sections cover the oil pump, overdrive unit, clutch and brake assemblies, planetary sets, one-way clutches, accumulators, solenoids, sensors, neutral switch, and upper and lower valve bodies.

Driveline chapters cover Dana Trac-Lok and Power-Lok differentials, full-floating and standard rear axles, axle-ratio identification, gear-tooth contact patterns, driveshaft phasing and runout, and universal-joint overhaul. Command-Trac diagnosis includes the vacuum-controlled axle-shift system, while the NP207/231 and NP/NV242 sections provide removal, disassembly, inspection, reassembly, adjustment, and testing coverage. Manual-transmission information is limited to removal, installation, and servicing; there is no comparable full internal manual-gearbox overhaul chapter.

Chassis, Electrical, and Workshop Reference

Brake coverage includes disc and drum systems, hydraulic bleeding, parking-brake service, caliper and wheel-cylinder repair, master-cylinder overhaul, and the Comanche height-sensing proportioning valve. Steering and front-suspension chapters address pressure testing, pump and gear repair, steering-column service, 4WD knuckles and ball joints, linkage, springs, control arms, track bar, wheel bearings, shocks, riding height, and alignment. The set also covers HVAC and A/C service, charging and starting systems, instrument-panel circuits, power accessories, wipers, emissions equipment, maintenance schedules, fluid capacities, and vacuum routing.

Representative figures include the 2.5L TBI System Wiring Diagram, Cherokee Engine Control System Wiring Diagram, AW-4 Transmission Components, Pressure Test Gauge Hookup, Command-Trac Vacuum Control System, and the Cherokee/Wagoneer A/C Heating System schematic. Electrical-component locator views cover Cherokee, Comanche, and Wagoneer. The final full-vehicle wiring set is labeled for Cherokee and Wagoneer; it is not a complete Comanche or Wrangler schematic package, although model-specific engine-control diagrams appear elsewhere.

Two repair cautions show the manual’s practical depth. The brake chapter warns against honing a “Bearingized” master-cylinder bore because it can cause premature rubber-part failure. The AW4 assembly section warns that forcing the oil pump into place can damage the stator-shaft seal rings.

Brake-hydraulic repair, refrigerant service, vehicle lifting, and AW4 stall or pressure testing require the specified equipment and shop safeguards. Higher-risk diagnosis and repair should be handled by a qualified technician.