Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2002 Volkswagen New Beetle GL, 1.9 PFACTORY OEM SERVICE PROCEDURE
On Board Diagnostic - 1.9L - Fuel Injection And Glow Plug - Engine Code(S): ALH (Hatchback)
- 01 On Board Diagnostic (OBD)
- General Information
- Description And Operation
- Specifications
- Diagnosis And Testing
- DTC Memory, Checking
- DTC Memory, Erasing
- Readiness Code, Displaying
- Readiness Code, Setting
- Function 03 - Performing Output Diagnostic Test Mode
- Function 08 - Reading Measured Value Block
- Measured Value Blocks, Evaluating
- Notes
- Evaluation: Injected Quantity Display
- Evaluation: Modulating Piston Displacement Sensor -G149- Voltage Display
- Evaluation: Mass Air Flow Frawn In (Specified) Display
- Evaluation: Mass Air Flow Drawn In (Actual) Display
- Evaluation: Start Of Injection Display (Specified)
- Evaluation: Start Of Injection Display (Actual)
- Evaluation: Brake Pedal Monitor Display
- Evaluation: Cruise Control System Display
- Evaluation: Fuel temperature Display
- Evaluation: Intake Air Temperature Display
- Evaluation: Engine Coolant Temperature Display
- Evaluation: Glow Readiness, Status Display
- Idle Speed Smooth Running Control, Evaluating Display
- Notes
- Evaluation: Auxiliary Heater Display
- Evaluation: Heater Element Activation Display
- Evaluation: Modulating Piston Displacement Sensor Voltage Display (Start And Stop Position Stops)
- Function 08 - Evaluating Measured Value Block
- Notes
- Evaluation: Start Of Injection (Actual) Display
- Evaluation: Cold Start Valve Duty Cycle Display
- Evaluation: Injected Quantity (Driver's Requirement) Display
- Evaluation: Injected Quantity Limitation Due To Engine Speed Display (Torque Limitation)
- Evaluation: Injection Quantity Limitation Due To Air Mass Drawn In Display (Smoke Prevention)
- Evaluation: Air Mass Drawn In Display
- Evaluation: Manifold Absolute Pressure Display (Boost Pressure)
- Evaluation: Throttle Position Display
- Evaluation: Boost Pressure Display (Actual)
- Special Tools
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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