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Home >> Volkswagen >> 1987 >> Jetta L4-1781cc 1.8L DOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Testing and Inspection >> Component Tests and General Diagnostics >> Idle Stabilizer Control
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Idle Stabilizer Control


When engine is idling, control current for idle stabilization is dependent on engine speed. Control current may fluctuate between 400 - 1100 milliamps dependent on engine load.

1. Ensure engine is at normal operating temperature (engine oil temperature 80°C (176°F) minimum), idle speed is within specifications and no engine vacuum leaks are present.
2. Ensure coolant temperature sensor is satisfactory.
3. Connect a test harness (VW 1315A/2 or equivalent) to idle stabilizer valve.
4. Set digital multimeter (No. US 1119 or equivalent) to milliamp range, then connect multimeter to adapter to measure control current.
5. Start engine and raise engine speed to a minimum of 2100 RPM four times, then let engine idle.
6. Measure control current. Multimeter should indicate 400-460 milliamps and fluctuate slightly.
7. Disconnect engine coolant temperature harness connector.
8. Measure control current. Multimeter should indicate approximately 430 milliamps (constant).
9. If specified values are not obtained, replace idle stabilizer control unit.

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