P158b Renault !link! -

fault code in Renault vehicles—frequently encountered in 1.5 dCi and 1.3 TCe engines (e.g., Clio V, Captur II)—specifically relates to the Flywheel Signal Information Crankshaft Position Sensor circuit

Difficulty restarting immediately (sometimes taking up to 10 seconds). p158b renault

  1. Reset the Fault Code: In some cases, resetting the fault code may resolve the issue. However, this is only a temporary solution and may not address the underlying problem.
  2. Update Software: If the issue is software-related, updating the software may resolve the problem.
  3. Replace Faulty Radar Sensor: If the radar sensor is faulty, replacing it may be necessary.
  4. Repair or Replace Wiring or Electrical Connections: If faulty wiring or electrical connections are causing the problem, repairing or replacing them may be necessary.
  5. Replace Faulty ECU: In some cases, replacing the ECU may be necessary.

Renault’s specific turbo geometry design on the 1.9 dCi was sensitive to "coking." The system relied on a specific vacuum pressure to operate the actuator. A common failure point—often misdiagnosed as the turbo itself—is the electro-valve (solenoid) that controls this vacuum. When this cheap plastic component fails, the turbo vanes default to a position that conflicts with the ECU’s mapping, causing P158b. fault code in Renault vehicles—frequently encountered in 1

Clean the Throttle Body: Carbon buildup can physically block the idle actuator from moving as intended. Cleaning the intake and throttle plate with a specialized cleaner can sometimes clear the fault. Reset the Fault Code : In some cases,

Conclusion

The P158B Renault is not a secret sports model or a lost prototype — it is the definitive late-production Renault 4 TL. While it lacks the nostalgic purity of the earliest R4s, it represents the model’s successful adaptation to changing times. For anyone seeking an affordable, easy-to-maintain entry into classic French motoring, the P158B offers a robust, practical, and historically meaningful choice — proof that even a humble utility car can evolve with dignity.

This paper investigates the obscure fault code P158b—often cited in technician forums as a cryptic "anti-pollution" or "variable geometry" failure—as a symptom of a larger systemic conflict between advanced forced induction and the limitations of late-1990s metallurgy. By analyzing the P158b code as a case study, we explore how the 1.9 dCi bridged the gap between mechanical diesel reliability and electronic complexity, creating a legacy that continues to influence the used car market today.

  • Remove the turbo (on K9K 1.5 dCi, the turbo is accessible from the top, but removal is easier from below).
  • Disassemble the VGT ring and clean all carbon deposits with a dedicated turbo cleaner or ultrasonic bath.
  • Alternatively, use an in-situ chemical turbo cleaner (e.g., Wynn’s or Liqui Moly turbo cleaner) as a temporary fix – but manual cleaning is far more effective.