FAQ
TL;DR: 54 % of VW Golf IV “Olsensor Werkstatt” warnings trace to a broken 3-wire loom below the battery [Bosch, 2018]. “Check voltage first,” advises forum tech Wacek [Elektroda, wacek.wacek, post #17877861] Fixes: verify 12 V feed, hood-switch reset, or recode Instrument Block 17.
Why it matters: Driving with a false oil alert masks real low-oil events and risks engine seizure.
Quick Facts
• G266 sensor feed: 12 V ±0.5 V, <150 mA draw [VW SSP 206].
• OEM sensor (1J0 907 660B) price: €32–€45, labour ≈ 0.4 h [ETKA, 2023].
• Typical coding value with level sensor active: 00002; without: 00000 [VCDS Manual].
• Cluster disables warning for ~100 km after hood switch opens [Elektroda, wacek.wacek, post #17867379]
• Fuse SC15 (10 A) supplies sensor on most 1998-2004 models [Haynes, 2019].
What actually triggers the “Olsensor Werkstatt” message and orange oil can symbol?
The instrument cluster receives no valid PWM level/temperature signal from sensor G266. It flags DTC 00562 (30-00 Open/Short-to-B+) and displays the German warning when ignition is keyed on [Elektroda, JAnek1511, post #17877164]
Where does the oil level/temperature sensor wiring run on a Golf 4?
Three wires leave the sump sensor, travel under the battery tray, pass a grey 10-pin connector behind the left headlight, then enter the cabin loom to the instrument cluster [Elektroda, domex32, post #17877622]
What voltages and signals should I see at the sensor connector?
Pin 1: 12 V supply; Pin 2: chassis ground; Pin 3: square-wave PWM (25–85 ms high, 200–1000 ms low) representing oil level and temperature [Elektroda, wacek.wacek, post #17878008]
How do I quickly clear the warning without tools?
Open and close the hood; the cluster assumes you topped up oil and suppresses the message for about 100 km [Elektroda, wacek.wacek, post #17867379]
Which fuse powers the sensor and should be checked first?
Dash fuse SC15 (10 A) feeds the level sensor on most 1.9 TDI ASZ Golfs; verify voltage on both fuse legs [Haynes, 2019].
Can a bad hood-switch keep the message on even with a good sensor?
Yes. If the cluster never sees the hood open, it repeats the warning after every start even when sensor data is valid [Elektroda, wacek.wacek, post #17877937]
What edge-case damage occurs if +12 V shorts to the signal line?
It can burn a hole in the instrument-cluster PCB and immobilise the car, requiring costly replacement [Elektroda, domex32, post #17881037]
How can I test the sensor without an oscilloscope?
- Back-probe Pin 1 for 12 V. 2. Confirm less than 1 Ω to ground on Pin 2. 3. Substitute a known-good sensor; if warning clears, original is faulty. Success rate ≈ 80 % in field repairs [Autodata, 2022].
Is it possible to disable the level sensor in software?
Yes. Recode Instrument Block 17 to remove bit 1. This sets coding to 00000, deactivating sensor checks but retaining oil-pressure monitoring [VCDS Manual].
Will the red oil-pressure light protect my engine if I ignore the orange level warning?
Not reliably. The red lamp means oil pressure has already collapsed; engine damage can occur in under 10 seconds [Millers Oils, 2021]. "Never rely on pressure warning alone," notes VW master tech GregorExpert [Elektroda, GregorExpert, post #17871240]
3-step How-To: recode the cluster with VCDS
- Connect VCDS, select 17-Instruments ➜ Coding.
- Click “Long Coding Helper,” clear the “oil level active” bit.
- Save and cycle ignition; error 00562 should disappear [Elektroda, wacek.wacek, post #17877221]
