Diagnostic Guide Library

Diagnose starter motor issues including solenoid, armature, and circuit faults. Covers cranking current analysis and voltage drop testing.

Measure battery health through internal resistance and conductance testing. Correlate results with capacity and cold cranking performance.

Diagnose Controller Area Network (CAN) communication faults using oscilloscope waveform analysis, termination resistance checks, and DTC interpretation.

Systematic approach to diagnosing ground faults, ground loops, and high-resistance ground connections that cause erratic electrical behaviour.

Systematic testing of fuses, relays, and circuit protection devices. Covers visual inspection, continuity testing, and relay coil/contact verification.

Technical comparison of R134a and R1234yf refrigerants including properties, compatibility, handling differences, and retrofit considerations.

Precise measurement techniques for superheat and subcooling — the two most important diagnostic parameters for evaluating refrigeration cycle health.

Comprehensive compressor health assessment including clutch testing, compression ratio analysis, oil level verification, and noise diagnostics.

Systematic approach to finding and confirming refrigerant leaks using electronic detectors, UV dye, nitrogen pressure testing, and visual inspection.

Diagnose uneven cooling, poor airflow, and distribution problems in bus cabin HVAC systems including duct inspection and blower motor testing.

Diagnose Anti-lock Braking System (ABS) and Electronic Braking System (EBS) faults including wheel speed sensors, modulator valves, and ECU communication.

Complete air dryer diagnostic and maintenance procedure including desiccant inspection, purge valve testing, heater verification, and performance validation.

Test and verify the multi-circuit protection valve that ensures brake circuit isolation. Critical safety component that prevents total brake failure from a single circuit leak.

Engineering approach to air reservoir sizing including volume calculations, pressure decay analysis, and regulatory compliance for minimum stored energy requirements.

Diagnose and adjust front/rear brake balance for optimal braking performance and stability. Covers load-sensing valves, ALB, and roller brake tester interpretation.

Comprehensive cooling system diagnosis including thermostat testing, coolant flow verification, pressure testing, and fan clutch/electric fan diagnostics.

Diagnose turbocharger issues including boost pressure analysis, shaft play measurement, wastegate/VGT testing, and oil supply verification.

Diagnose common rail diesel injection issues including rail pressure analysis, injector balance testing, glow plug verification, and fuel system bleeding.

Safety procedures and diagnostic approach for electric vehicle high-voltage systems including isolation testing, battery management, and thermal monitoring.

Diagnose electric vehicle thermal management including battery cooling/heating, cabin heat pump operation, inverter cooling, and integrated thermal circuits.

Diagnose common rail fuel system pressure faults including HP pump wear, injector leak-back, rail pressure sensor drift, and pressure control valve failures.

Diagnose turbocharger boost pressure faults including VGT vane sticking, wastegate failures, boost leaks, and bearing wear.

Diagnose DPF soot loading, failed regeneration, excessive backpressure, and ash accumulation issues.

Diagnose SCR catalyst efficiency, AdBlue dosing faults, NOx sensor failures, and urea crystallization issues.

Diagnose EGR valve faults, cooler leaks, carbon buildup, and the NOx-PM trade-off in diesel engines.

Diagnose the Cummins XPI (Xtreme Pressure Injection) high-pressure common rail system. Covers gear pump, high-pressure pump, fuel rail, and injectors with pressures up to 2400 bar.

Diagnose the Variable Geometry Turbocharger on Cummins X11. Covers VGT actuator, vane position, boost pressure, and turbo shaft play.

Diagnose the complete Cummins Single Module aftertreatment system: DOC, DPF, decomposition tube with mixer, SCR catalyst, and ASC catalyst.

Diagnose the Cummins CM2670 Electronic Control Module, its 40+ sensor inputs, actuator outputs, and J1939/J1708 data link communications.

Step-by-step overhead valve adjustment for the Cummins X11 engine. Covers intake valve lash, exhaust valve lash, injector timing, and engine brake adjustment.

Complete valve clearance adjustment procedure for the MAN D2676 LOH engine including inlet, exhaust, and EVB (Exhaust Valve Brake) clearances. Follows firing order 1-5-3-6-2-4 with 120-degree crankshaft rotation between cylinders.

Pressure leak test procedure for the MAN D2676 AGR (Abgasrueckfuehrung / Exhaust Gas Recirculation) system. Tests the AGR cooler, AGR valve, and all connecting pipework for internal and external leaks.

Procedure for replacing the common rail pressure sensor on the MAN D2676 engine. Includes torque specifications, sealing requirements, and post-replacement calibration.

Procedure for removing and installing the Bosch EDC17 engine control unit on the MAN D2676. Includes two-stage torque sequence, connector handling, and post-installation programming requirements.

Quick reference for all MAN D2676 LOH filling quantities including engine oil, gearbox, retarder, hydraulic system, axle differentials, and A/C refrigerant. Covers oil grades and specifications.