Renault Grand Scenic P1629 Engine Trouble Code
What is Renault Grand Scenic P1629?
Renault Grand Scenic P1629 code can indicate a faulty oxygen sensor, which may eventually damage the catalytic converter (repair cost: $2,000–$2,200). Professional diagnosis costs around $200–$210. Oxygen sensors are often straightforward to replace — check your owner's manual for location and instructions. This issue should be addressed promptly to prevent further damage.
P1629 on the Renault Grand Scenic
For Renault Grand Scenic owners, diagnosing P1629 correctly requires ruling out a faulty camshaft position sensor before replacing more expensive components. The sensor wiring harness on this model runs close to the exhaust manifold and is prone to heat-related insulation damage.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Renault Grand Scenic |
| Brand: | Renault |
| Model: | Grand Scenic |
| Code: | P1629 |
P1629 Renault Grand Scenic Symptoms
Check Engine Light
Illuminated Renault Grand Scenic dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Renault Grand Scenic
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Renault Grand Scenic
Increased Emissions
Failed emissions test due to P1629
P1629 Code Structure
Understanding what each digit means in the P1629 powertrain trouble code:
| P | 1 | 6 | 2 | 9 |
|---|---|---|---|---|
| Powertrain Code | Fuel And Air Metering | Fuel Temperature Sensor B Circuit Range/Performance | Turbocharger Boost Sensor A Circuit Low | Reverse Input Circuit |
How to Fix Renault Grand Scenic P1629
Diagnostic Steps:
Regarding P1629, carefully inspect the wire harness near the intake manifold bracket, best accessed from below near the oil filter. Look for chafing, pinching, or damaged insulation.
Repair Solution:
Disconnected, dirty, or fouled spark plugs commonly prevent proper engine operation. Replace spark plugs every season or 25 hours. Verify proper spark plug gap. If plugs are good, check ignition components: spark plug wires, coils, and ignition module.
Technical Notes:
Parts or components should not be replaced based solely on P1629 DTC. Consult your vehicle service manual for proper diagnostic procedures, possible causes, and required testing before replacement.
Renault Grand Scenic P1629 Repair Cost
On the Renault Grand Scenic, secondary air injection pump replacement for a P1629 code runs $350–$600. Because the pump is only active during cold starts, symptoms are easily missed. Requesting a cold-start emissions test at the workshop will confirm whether the pump is operating.
P1629 Description
P1629 engine trouble code is related to Reverse Input Circuit.
Main Cause
The primary reason for P1629 OBD-II Engine Trouble Code is: Fuel Temperature Sensor B Circuit Range/Performance.
Common P1629 Misdiagnosis on the Renault Grand Scenic
When P1629 triggers on the Renault Grand Scenic, a flashing check-engine light (as opposed to a steady one) indicates an active misfire. Misfire codes are commonly misdiagnosed as sensor faults; always rule out ignition and fuel delivery issues before testing sensors.
DIY Repair Guide: P1629 on Renault Grand Scenic
Replacing the oxygen sensor on the Renault Grand Scenic requires an O2 sensor socket (22mm or 7/8") and penetrating oil applied 24 hours in advance. On vehicles over five years old, the sensor threads often corrode into the bung; heat from a propane torch (briefly applied) is usually sufficient to free them.
Preventing P1629 on the Renault Grand Scenic
For turbocharged Renault Grand Scenic models, allowing the engine to idle for 60–90 seconds before shutdown after hard driving reduces turbocharger heat soak and prevents the coking of oil that blocks VVT galleries — a known secondary trigger of P1629.
Frequently Asked Questions — Renault Grand Scenic P1629
A: Yes. A weak battery causes voltage drop during cranking that confuses the ECU and can store a range of fault codes. Always rule out battery and charging system health before diagnosing sensor-related codes.