P158b Renault -

By 1978, the Renault 4 was already 17 years old. Competitors like the Peugeot 104, Fiat 127, and even Renault’s own newer models (Renault 5) offered more modern features. The P158B update was Renault’s attempt to:

Remove the retaining bolt holding the sensor in place and pull it out. Inspect the tip. If it is caked in black grime or metallic fuzz, wipe it clean with a microfiber cloth and brake cleaner. 4. Measure Electrical Resistance Using a digital multimeter set to the Ohms ( Ωcap omega p158b renault